commit 54117e62a6ac883d29037e402f7e0e2dd538c9ff Author: Klaus2m5 Date: Sat Oct 26 17:04:12 2013 +0200 redistribution The original EhBASIC website is unavailable at this time. This repository restores the availability of the original EhBASIC source and documentation. diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..412eeda --- /dev/null +++ b/.gitattributes @@ -0,0 +1,22 @@ +# Auto detect text files and perform LF normalization +* text=auto + +# Custom for Visual Studio +*.cs diff=csharp +*.sln merge=union +*.csproj merge=union +*.vbproj merge=union +*.fsproj merge=union +*.dbproj merge=union + +# Standard to msysgit +*.doc diff=astextplain +*.DOC diff=astextplain +*.docx diff=astextplain +*.DOCX diff=astextplain +*.dot diff=astextplain +*.DOT diff=astextplain +*.pdf diff=astextplain +*.PDF diff=astextplain +*.rtf diff=astextplain +*.RTF diff=astextplain diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..b9d6bd9 --- /dev/null +++ b/.gitignore @@ -0,0 +1,215 @@ +################# +## Eclipse +################# + +*.pydevproject +.project +.metadata +bin/ +tmp/ +*.tmp +*.bak +*.swp +*~.nib +local.properties +.classpath +.settings/ +.loadpath + +# External tool builders +.externalToolBuilders/ + +# Locally stored "Eclipse launch configurations" +*.launch + +# CDT-specific +.cproject + +# PDT-specific +.buildpath + + +################# +## Visual Studio +################# + +## Ignore Visual Studio temporary files, build results, and +## files generated by popular Visual Studio add-ons. + +# User-specific files +*.suo +*.user +*.sln.docstates + +# Build results + +[Dd]ebug/ +[Rr]elease/ +x64/ +build/ +[Bb]in/ +[Oo]bj/ + +# MSTest test Results +[Tt]est[Rr]esult*/ +[Bb]uild[Ll]og.* + +*_i.c +*_p.c +*.ilk +*.meta +*.obj +*.pch +*.pdb +*.pgc +*.pgd +*.rsp +*.sbr +*.tlb +*.tli +*.tlh +*.tmp +*.tmp_proj +*.log +*.vspscc +*.vssscc +.builds +*.pidb +*.log +*.scc + +# Visual C++ cache files +ipch/ +*.aps +*.ncb +*.opensdf +*.sdf +*.cachefile + +# Visual Studio profiler +*.psess +*.vsp +*.vspx + +# Guidance Automation Toolkit +*.gpState + +# ReSharper is a .NET coding add-in +_ReSharper*/ +*.[Rr]e[Ss]harper + +# TeamCity is a build add-in +_TeamCity* + +# DotCover is a Code Coverage Tool +*.dotCover + +# NCrunch +*.ncrunch* +.*crunch*.local.xml + +# Installshield output folder +[Ee]xpress/ + +# DocProject is a documentation generator add-in +DocProject/buildhelp/ +DocProject/Help/*.HxT +DocProject/Help/*.HxC +DocProject/Help/*.hhc +DocProject/Help/*.hhk +DocProject/Help/*.hhp +DocProject/Help/Html2 +DocProject/Help/html + +# Click-Once directory +publish/ + +# Publish Web Output +*.Publish.xml +*.pubxml + +# NuGet Packages Directory +## TODO: If you have NuGet Package Restore enabled, uncomment the next line +#packages/ + +# Windows Azure Build Output +csx +*.build.csdef + +# Windows Store app package directory +AppPackages/ + +# Others +sql/ +*.Cache +ClientBin/ +[Ss]tyle[Cc]op.* +~$* +*~ +*.dbmdl +*.[Pp]ublish.xml +*.pfx +*.publishsettings + +# RIA/Silverlight projects +Generated_Code/ + +# Backup & report files from converting an old project file to a newer +# Visual Studio version. Backup files are not needed, because we have git ;-) +_UpgradeReport_Files/ +Backup*/ +UpgradeLog*.XML +UpgradeLog*.htm + +# SQL Server files +App_Data/*.mdf +App_Data/*.ldf + +############# +## Windows detritus +############# + +# Windows image file caches +Thumbs.db +ehthumbs.db + +# Folder config file +Desktop.ini + +# Recycle Bin used on file shares +$RECYCLE.BIN/ + +# Mac crap +.DS_Store + + +############# +## Python +############# + +*.py[co] + +# Packages +*.egg +*.egg-info +dist/ +build/ +eggs/ +parts/ +var/ +sdist/ +develop-eggs/ +.installed.cfg + +# Installer logs +pip-log.txt + +# Unit test / coverage reports +.coverage +.tox + +#Translations +*.mo + +#Mr Developer +.mr.developer.cfg diff --git a/Enhanced_6502_BASIC_reference_manual.pdf b/Enhanced_6502_BASIC_reference_manual.pdf new file mode 100644 index 0000000..1907cbd Binary files /dev/null and b/Enhanced_6502_BASIC_reference_manual.pdf differ diff --git a/basic.asm b/basic.asm new file mode 100644 index 0000000..df9a9c8 --- /dev/null +++ b/basic.asm @@ -0,0 +1,8691 @@ + +; Enhanced BASIC to assemble under 6502 simulator, $ver 2.22 + +; $E7E1 $E7CF $E7C6 $E7D3 $E7D1 $E7D5 $E7CF $E81E $E825 + +; 2.00 new revision numbers start here +; 2.01 fixed LCASE$() and UCASE$() +; 2.02 new get value routine done +; 2.03 changed RND() to galoise method +; 2.04 fixed SPC() +; 2.05 new get value routine fixed +; 2.06 changed USR() code +; 2.07 fixed STR$() +; 2.08 changed INPUT and READ to remove need for $00 start to input buffer +; 2.09 fixed RND() +; 2.10 integrated missed changes from an earlier version +; 2.20 added ELSE to IF .. THEN and fixed IF .. GOTO to cause error +; 2.21 fixed IF .. THEN RETURN to not cause error +; 2.22 fixed RND() breaking the get byte routine + +; zero page use .. + +LAB_WARM = $00 ; BASIC warm start entry point +Wrmjpl = LAB_WARM+1; BASIC warm start vector jump low byte +Wrmjph = LAB_WARM+2; BASIC warm start vector jump high byte + +Usrjmp = $0A ; USR function JMP address +Usrjpl = Usrjmp+1 ; USR function JMP vector low byte +Usrjph = Usrjmp+2 ; USR function JMP vector high byte +Nullct = $0D ; nulls output after each line +TPos = $0E ; BASIC terminal position byte +TWidth = $0F ; BASIC terminal width byte +Iclim = $10 ; input column limit +Itempl = $11 ; temporary integer low byte +Itemph = Itempl+1 ; temporary integer high byte + +nums_1 = Itempl ; number to bin/hex string convert MSB +nums_2 = nums_1+1 ; number to bin/hex string convert +nums_3 = nums_1+2 ; number to bin/hex string convert LSB + +Srchc = $5B ; search character +Temp3 = Srchc ; temp byte used in number routines +Scnquo = $5C ; scan-between-quotes flag +Asrch = Scnquo ; alt search character + +XOAw_l = Srchc ; eXclusive OR, OR and AND word low byte +XOAw_h = Scnquo ; eXclusive OR, OR and AND word high byte + +Ibptr = $5D ; input buffer pointer +Dimcnt = Ibptr ; # of dimensions +Tindx = Ibptr ; token index + +Defdim = $5E ; default DIM flag +Dtypef = $5F ; data type flag, $FF=string, $00=numeric +Oquote = $60 ; open quote flag (b7) (Flag: DATA scan; LIST quote; memory) +Gclctd = $60 ; garbage collected flag +Sufnxf = $61 ; subscript/FNX flag, 1xxx xxx = FN(0xxx xxx) +Imode = $62 ; input mode flag, $00=INPUT, $80=READ + +Cflag = $63 ; comparison evaluation flag + +TabSiz = $64 ; TAB step size (was input flag) + +next_s = $65 ; next descriptor stack address + + ; these two bytes form a word pointer to the item + ; currently on top of the descriptor stack +last_sl = $66 ; last descriptor stack address low byte +last_sh = $67 ; last descriptor stack address high byte (always $00) + +des_sk = $68 ; descriptor stack start address (temp strings) + +; = $70 ; End of descriptor stack + +ut1_pl = $71 ; utility pointer 1 low byte +ut1_ph = ut1_pl+1 ; utility pointer 1 high byte +ut2_pl = $73 ; utility pointer 2 low byte +ut2_ph = ut2_pl+1 ; utility pointer 2 high byte + +Temp_2 = ut1_pl ; temp byte for block move + +FACt_1 = $75 ; FAC temp mantissa1 +FACt_2 = FACt_1+1 ; FAC temp mantissa2 +FACt_3 = FACt_2+1 ; FAC temp mantissa3 + +dims_l = FACt_2 ; array dimension size low byte +dims_h = FACt_3 ; array dimension size high byte + +TempB = $78 ; temp page 0 byte + +Smeml = $79 ; start of mem low byte (Start-of-Basic) +Smemh = Smeml+1 ; start of mem high byte (Start-of-Basic) +Svarl = $7B ; start of vars low byte (Start-of-Variables) +Svarh = Svarl+1 ; start of vars high byte (Start-of-Variables) +Sarryl = $7D ; var mem end low byte (Start-of-Arrays) +Sarryh = Sarryl+1 ; var mem end high byte (Start-of-Arrays) +Earryl = $7F ; array mem end low byte (End-of-Arrays) +Earryh = Earryl+1 ; array mem end high byte (End-of-Arrays) +Sstorl = $81 ; string storage low byte (String storage (moving down)) +Sstorh = Sstorl+1 ; string storage high byte (String storage (moving down)) +Sutill = $83 ; string utility ptr low byte +Sutilh = Sutill+1 ; string utility ptr high byte +Ememl = $85 ; end of mem low byte (Limit-of-memory) +Ememh = Ememl+1 ; end of mem high byte (Limit-of-memory) +Clinel = $87 ; current line low byte (Basic line number) +Clineh = Clinel+1 ; current line high byte (Basic line number) +Blinel = $89 ; break line low byte (Previous Basic line number) +Blineh = Blinel+1 ; break line high byte (Previous Basic line number) + +Cpntrl = $8B ; continue pointer low byte +Cpntrh = Cpntrl+1 ; continue pointer high byte + +Dlinel = $8D ; current DATA line low byte +Dlineh = Dlinel+1 ; current DATA line high byte + +Dptrl = $8F ; DATA pointer low byte +Dptrh = Dptrl+1 ; DATA pointer high byte + +Rdptrl = $91 ; read pointer low byte +Rdptrh = Rdptrl+1 ; read pointer high byte + +Varnm1 = $93 ; current var name 1st byte +Varnm2 = Varnm1+1 ; current var name 2nd byte + +Cvaral = $95 ; current var address low byte +Cvarah = Cvaral+1 ; current var address high byte + +Frnxtl = $97 ; var pointer for FOR/NEXT low byte +Frnxth = Frnxtl+1 ; var pointer for FOR/NEXT high byte + +Tidx1 = Frnxtl ; temp line index + +Lvarpl = Frnxtl ; let var pointer low byte +Lvarph = Frnxth ; let var pointer high byte + +prstk = $99 ; precedence stacked flag + +comp_f = $9B ; compare function flag, bits 0,1 and 2 used + ; bit 2 set if > + ; bit 1 set if = + ; bit 0 set if < + +func_l = $9C ; function pointer low byte +func_h = func_l+1 ; function pointer high byte + +garb_l = func_l ; garbage collection working pointer low byte +garb_h = func_h ; garbage collection working pointer high byte + +des_2l = $9E ; string descriptor_2 pointer low byte +des_2h = des_2l+1 ; string descriptor_2 pointer high byte + +g_step = $A0 ; garbage collect step size + +Fnxjmp = $A1 ; jump vector for functions +Fnxjpl = Fnxjmp+1 ; functions jump vector low byte +Fnxjph = Fnxjmp+2 ; functions jump vector high byte + +g_indx = Fnxjpl ; garbage collect temp index + +FAC2_r = $A3 ; FAC2 rounding byte + +Adatal = $A4 ; array data pointer low byte +Adatah = Adatal+1 ; array data pointer high byte + +Nbendl = Adatal ; new block end pointer low byte +Nbendh = Adatah ; new block end pointer high byte + +Obendl = $A6 ; old block end pointer low byte +Obendh = Obendl+1 ; old block end pointer high byte + +numexp = $A8 ; string to float number exponent count +expcnt = $A9 ; string to float exponent count + +numbit = numexp ; bit count for array element calculations + +numdpf = $AA ; string to float decimal point flag +expneg = $AB ; string to float eval exponent -ve flag + +Astrtl = numdpf ; array start pointer low byte +Astrth = expneg ; array start pointer high byte + +Histrl = numdpf ; highest string low byte +Histrh = expneg ; highest string high byte + +Baslnl = numdpf ; BASIC search line pointer low byte +Baslnh = expneg ; BASIC search line pointer high byte + +Fvar_l = numdpf ; find/found variable pointer low byte +Fvar_h = expneg ; find/found variable pointer high byte + +Ostrtl = numdpf ; old block start pointer low byte +Ostrth = expneg ; old block start pointer high byte + +Vrschl = numdpf ; variable search pointer low byte +Vrschh = expneg ; variable search pointer high byte + +FAC1_e = $AC ; FAC1 exponent +FAC1_1 = FAC1_e+1 ; FAC1 mantissa1 +FAC1_2 = FAC1_e+2 ; FAC1 mantissa2 +FAC1_3 = FAC1_e+3 ; FAC1 mantissa3 +FAC1_s = FAC1_e+4 ; FAC1 sign (b7) + +str_ln = FAC1_e ; string length +str_pl = FAC1_1 ; string pointer low byte +str_ph = FAC1_2 ; string pointer high byte + +des_pl = FAC1_2 ; string descriptor pointer low byte +des_ph = FAC1_3 ; string descriptor pointer high byte + +mids_l = FAC1_3 ; MID$ string temp length byte + +negnum = $B1 ; string to float eval -ve flag +numcon = $B1 ; series evaluation constant count + +FAC1_o = $B2 ; FAC1 overflow byte + +FAC2_e = $B3 ; FAC2 exponent +FAC2_1 = FAC2_e+1 ; FAC2 mantissa1 +FAC2_2 = FAC2_e+2 ; FAC2 mantissa2 +FAC2_3 = FAC2_e+3 ; FAC2 mantissa3 +FAC2_s = FAC2_e+4 ; FAC2 sign (b7) + +FAC_sc = $B8 ; FAC sign comparison, Acc#1 vs #2 +FAC1_r = $B9 ; FAC1 rounding byte + +ssptr_l = FAC_sc ; string start pointer low byte +ssptr_h = FAC1_r ; string start pointer high byte + +sdescr = FAC_sc ; string descriptor pointer + +csidx = $BA ; line crunch save index +Asptl = csidx ; array size/pointer low byte +Aspth = $BB ; array size/pointer high byte + +Btmpl = Asptl ; BASIC pointer temp low byte +Btmph = Aspth ; BASIC pointer temp low byte + +Cptrl = Asptl ; BASIC pointer temp low byte +Cptrh = Aspth ; BASIC pointer temp low byte + +Sendl = Asptl ; BASIC pointer temp low byte +Sendh = Aspth ; BASIC pointer temp low byte + +LAB_IGBY = $BC ; get next BASIC byte subroutine + +LAB_GBYT = $C2 ; get current BASIC byte subroutine +Bpntrl = $C3 ; BASIC execute (get byte) pointer low byte +Bpntrh = Bpntrl+1 ; BASIC execute (get byte) pointer high byte + +; = $D7 ; end of get BASIC char subroutine + +Rbyte4 = $D8 ; extra PRNG byte +Rbyte1 = Rbyte4+1 ; most significant PRNG byte +Rbyte2 = Rbyte4+2 ; middle PRNG byte +Rbyte3 = Rbyte4+3 ; least significant PRNG byte + +NmiBase = $DC ; NMI handler enabled/setup/triggered flags + ; bit function + ; === ======== + ; 7 interrupt enabled + ; 6 interrupt setup + ; 5 interrupt happened +; = $DD ; NMI handler addr low byte +; = $DE ; NMI handler addr high byte +IrqBase = $DF ; IRQ handler enabled/setup/triggered flags +; = $E0 ; IRQ handler addr low byte +; = $E1 ; IRQ handler addr high byte + +; = $DE ; unused +; = $DF ; unused +; = $E0 ; unused +; = $E1 ; unused +; = $E2 ; unused +; = $E3 ; unused +; = $E4 ; unused +; = $E5 ; unused +; = $E6 ; unused +; = $E7 ; unused +; = $E8 ; unused +; = $E9 ; unused +; = $EA ; unused +; = $EB ; unused +; = $EC ; unused +; = $ED ; unused +; = $EE ; unused + +Decss = $EF ; number to decimal string start +Decssp1 = Decss+1 ; number to decimal string start + +; = $FF ; decimal string end + +; token values needed for BASIC + +; primary command tokens (can start a statement) + +TK_END = $80 ; END token +TK_FOR = TK_END+1 ; FOR token +TK_NEXT = TK_FOR+1 ; NEXT token +TK_DATA = TK_NEXT+1 ; DATA token +TK_INPUT = TK_DATA+1 ; INPUT token +TK_DIM = TK_INPUT+1 ; DIM token +TK_READ = TK_DIM+1 ; READ token +TK_LET = TK_READ+1 ; LET token +TK_DEC = TK_LET+1 ; DEC token +TK_GOTO = TK_DEC+1 ; GOTO token +TK_RUN = TK_GOTO+1 ; RUN token +TK_IF = TK_RUN+1 ; IF token +TK_RESTORE = TK_IF+1 ; RESTORE token +TK_GOSUB = TK_RESTORE+1 ; GOSUB token +TK_RETIRQ = TK_GOSUB+1 ; RETIRQ token +TK_RETNMI = TK_RETIRQ+1 ; RETNMI token +TK_RETURN = TK_RETNMI+1 ; RETURN token +TK_REM = TK_RETURN+1 ; REM token +TK_STOP = TK_REM+1 ; STOP token +TK_ON = TK_STOP+1 ; ON token +TK_NULL = TK_ON+1 ; NULL token +TK_INC = TK_NULL+1 ; INC token +TK_WAIT = TK_INC+1 ; WAIT token +TK_LOAD = TK_WAIT+1 ; LOAD token +TK_SAVE = TK_LOAD+1 ; SAVE token +TK_DEF = TK_SAVE+1 ; DEF token +TK_POKE = TK_DEF+1 ; POKE token +TK_DOKE = TK_POKE+1 ; DOKE token +TK_CALL = TK_DOKE+1 ; CALL token +TK_DO = TK_CALL+1 ; DO token +TK_LOOP = TK_DO+1 ; LOOP token +TK_PRINT = TK_LOOP+1 ; PRINT token +TK_CONT = TK_PRINT+1 ; CONT token +TK_LIST = TK_CONT+1 ; LIST token +TK_CLEAR = TK_LIST+1 ; CLEAR token +TK_NEW = TK_CLEAR+1 ; NEW token +TK_WIDTH = TK_NEW+1 ; WIDTH token +TK_GET = TK_WIDTH+1 ; GET token +TK_SWAP = TK_GET+1 ; SWAP token +TK_BITSET = TK_SWAP+1 ; BITSET token +TK_BITCLR = TK_BITSET+1 ; BITCLR token +TK_IRQ = TK_BITCLR+1 ; IRQ token +TK_NMI = TK_IRQ+1 ; NMI token + +; secondary command tokens, can't start a statement + +TK_TAB = TK_NMI+1 ; TAB token +TK_ELSE = TK_TAB+1 ; ELSE token +TK_TO = TK_ELSE+1 ; TO token +TK_FN = TK_TO+1 ; FN token +TK_SPC = TK_FN+1 ; SPC token +TK_THEN = TK_SPC+1 ; THEN token +TK_NOT = TK_THEN+1 ; NOT token +TK_STEP = TK_NOT+1 ; STEP token +TK_UNTIL = TK_STEP+1 ; UNTIL token +TK_WHILE = TK_UNTIL+1 ; WHILE token +TK_OFF = TK_WHILE+1 ; OFF token + +; opperator tokens + +TK_PLUS = TK_OFF+1 ; + token +TK_MINUS = TK_PLUS+1 ; - token +TK_MUL = TK_MINUS+1 ; * token +TK_DIV = TK_MUL+1 ; / token +TK_POWER = TK_DIV+1 ; ^ token +TK_AND = TK_POWER+1 ; AND token +TK_EOR = TK_AND+1 ; EOR token +TK_OR = TK_EOR+1 ; OR token +TK_RSHIFT = TK_OR+1 ; RSHIFT token +TK_LSHIFT = TK_RSHIFT+1 ; LSHIFT token +TK_GT = TK_LSHIFT+1 ; > token +TK_EQUAL = TK_GT+1 ; = token +TK_LT = TK_EQUAL+1 ; < token + +; functions tokens + +TK_SGN = TK_LT+1 ; SGN token +TK_INT = TK_SGN+1 ; INT token +TK_ABS = TK_INT+1 ; ABS token +TK_USR = TK_ABS+1 ; USR token +TK_FRE = TK_USR+1 ; FRE token +TK_POS = TK_FRE+1 ; POS token +TK_SQR = TK_POS+1 ; SQR token +TK_RND = TK_SQR+1 ; RND token +TK_LOG = TK_RND+1 ; LOG token +TK_EXP = TK_LOG+1 ; EXP token +TK_COS = TK_EXP+1 ; COS token +TK_SIN = TK_COS+1 ; SIN token +TK_TAN = TK_SIN+1 ; TAN token +TK_ATN = TK_TAN+1 ; ATN token +TK_PEEK = TK_ATN+1 ; PEEK token +TK_DEEK = TK_PEEK+1 ; DEEK token +TK_SADD = TK_DEEK+1 ; SADD token +TK_LEN = TK_SADD+1 ; LEN token +TK_STRS = TK_LEN+1 ; STR$ token +TK_VAL = TK_STRS+1 ; VAL token +TK_ASC = TK_VAL+1 ; ASC token +TK_UCASES = TK_ASC+1 ; UCASE$ token +TK_LCASES = TK_UCASES+1 ; LCASE$ token +TK_CHRS = TK_LCASES+1 ; CHR$ token +TK_HEXS = TK_CHRS+1 ; HEX$ token +TK_BINS = TK_HEXS+1 ; BIN$ token +TK_BITTST = TK_BINS+1 ; BITTST token +TK_MAX = TK_BITTST+1 ; MAX token +TK_MIN = TK_MAX+1 ; MIN token +TK_PI = TK_MIN+1 ; PI token +TK_TWOPI = TK_PI+1 ; TWOPI token +TK_VPTR = TK_TWOPI+1 ; VARPTR token +TK_LEFTS = TK_VPTR+1 ; LEFT$ token +TK_RIGHTS = TK_LEFTS+1 ; RIGHT$ token +TK_MIDS = TK_RIGHTS+1 ; MID$ token + +; offsets from a base of X or Y + +PLUS_0 = $00 ; X or Y plus 0 +PLUS_1 = $01 ; X or Y plus 1 +PLUS_2 = $02 ; X or Y plus 2 +PLUS_3 = $03 ; X or Y plus 3 + +LAB_STAK = $0100 ; stack bottom, no offset + +LAB_SKFE = LAB_STAK+$FE + ; flushed stack address +LAB_SKFF = LAB_STAK+$FF + ; flushed stack address + +ccflag = $0200 ; BASIC CTRL-C flag, 00 = enabled, 01 = dis +ccbyte = ccflag+1 ; BASIC CTRL-C byte +ccnull = ccbyte+1 ; BASIC CTRL-C byte timeout + +VEC_CC = ccnull+1 ; ctrl c check vector + +VEC_IN = VEC_CC+2 ; input vector +VEC_OUT = VEC_IN+2 ; output vector +VEC_LD = VEC_OUT+2 ; load vector +VEC_SV = VEC_LD+2 ; save vector + +; Ibuffs can now be anywhere in RAM, ensure that the max length is < $80 + +Ibuffs = IRQ_vec+$14 + ; start of input buffer after IRQ/NMI code +Ibuffe = Ibuffs+$47; end of input buffer + +Ram_base = $0300 ; start of user RAM (set as needed, should be page aligned) +Ram_top = $C000 ; end of user RAM+1 (set as needed, should be page aligned) + +; This start can be changed to suit your system + + *= $C000 + +; BASIC cold start entry point + +; new page 2 initialisation, copy block to ccflag on + +LAB_COLD + LDY #PG2_TABE-PG2_TABS-1 + ; byte count-1 +LAB_2D13 + LDA PG2_TABS,Y ; get byte + STA ccflag,Y ; store in page 2 + DEY ; decrement count + BPL LAB_2D13 ; loop if not done + + LDX #$FF ; set byte + STX Clineh ; set current line high byte (set immediate mode) + TXS ; reset stack pointer + + LDA #$4C ; code for JMP + STA Fnxjmp ; save for jump vector for functions + +; copy block from LAB_2CEE to $00BC - $00D3 + + LDX #StrTab-LAB_2CEE ; set byte count +LAB_2D4E + LDA LAB_2CEE-1,X ; get byte from table + STA LAB_IGBY-1,X ; save byte in page zero + DEX ; decrement count + BNE LAB_2D4E ; loop if not all done + +; copy block from StrTab to $0000 - $0012 + +LAB_GMEM + LDX #EndTab-StrTab-1 ; set byte count-1 +TabLoop + LDA StrTab,X ; get byte from table + STA PLUS_0,X ; save byte in page zero + DEX ; decrement count + BPL TabLoop ; loop if not all done + +; set-up start values + + LDA #$00 ; clear A + STA NmiBase ; clear NMI handler enabled flag + STA IrqBase ; clear IRQ handler enabled flag + STA FAC1_o ; clear FAC1 overflow byte + STA last_sh ; clear descriptor stack top item pointer high byte + + LDA #$0E ; set default tab size + STA TabSiz ; save it + LDA #$03 ; set garbage collect step size for descriptor stack + STA g_step ; save it + LDX #des_sk ; descriptor stack start + STX next_s ; set descriptor stack pointer + JSR LAB_CRLF ; print CR/LF + LDA #LAB_MSZM ; point to memory size message (high addr) + JSR LAB_18C3 ; print null terminated string from memory + JSR LAB_INLN ; print "? " and get BASIC input + STX Bpntrl ; set BASIC execute pointer low byte + STY Bpntrh ; set BASIC execute pointer high byte + JSR LAB_GBYT ; get last byte back + + BNE LAB_2DAA ; branch if not null (user typed something) + + LDY #$00 ; else clear Y + ; character was null so get memory size the hard way + ; we get here with Y=0 and Itempl/h = Ram_base +LAB_2D93 + INC Itempl ; increment temporary integer low byte + BNE LAB_2D99 ; branch if no overflow + + INC Itemph ; increment temporary integer high byte + LDA Itemph ; get high byte + CMP #>Ram_top ; compare with top of RAM+1 + BEQ LAB_2DB6 ; branch if match (end of user RAM) + +LAB_2D99 + LDA #$55 ; set test byte + STA (Itempl),Y ; save via temporary integer + CMP (Itempl),Y ; compare via temporary integer + BNE LAB_2DB6 ; branch if fail + + ASL ; shift test byte left (now $AA) + STA (Itempl),Y ; save via temporary integer + CMP (Itempl),Y ; compare via temporary integer + BEQ LAB_2D93 ; if ok go do next byte + + BNE LAB_2DB6 ; branch if fail + +LAB_2DAA + JSR LAB_2887 ; get FAC1 from string + LDA FAC1_e ; get FAC1 exponent + CMP #$98 ; compare with exponent = 2^24 + BCS LAB_GMEM ; if too large go try again + + JSR LAB_F2FU ; save integer part of FAC1 in temporary integer + ; (no range check) + +LAB_2DB6 + LDA Itempl ; get temporary integer low byte + LDY Itemph ; get temporary integer high byte + CPY #Ram_top ; compare with top of RAM high byte +; BCC MEM_OK ; branch if < RAM top + +; BNE LAB_GMEM ; if too large go try again + ; else was = so compare low bytes +; CMP #Ram_base ; set start addr high byte + STY Smeml ; save start of mem low byte + STX Smemh ; save start of mem high byte + +; this line is only needed if Ram_base is not $xx00 + +; LDY #$00 ; clear Y + TYA ; clear A + STA (Smeml),Y ; clear first byte + INC Smeml ; increment start of mem low byte + +; these two lines are only needed if Ram_base is $xxFF + +; BNE LAB_2E05 ; branch if no rollover + +; INC Smemh ; increment start of mem high byte +LAB_2E05 + JSR LAB_CRLF ; print CR/LF + JSR LAB_1463 ; do "NEW" and "CLEAR" + LDA Ememl ; get end of mem low byte + SEC ; set carry for subtract + SBC Smeml ; subtract start of mem low byte + TAX ; copy to X + LDA Ememh ; get end of mem high byte + SBC Smemh ; subtract start of mem high byte + JSR LAB_295E ; print XA as unsigned integer (bytes free) + LDA #LAB_SMSG ; point to sign-on message (high addr) + JSR LAB_18C3 ; print null terminated string from memory + LDA #LAB_1274 ; warm start vector high byte + STA Wrmjpl ; save warm start vector low byte + STY Wrmjph ; save warm start vector high byte + JMP (Wrmjpl) ; go do warm start + +; open up space in memory +; move (Ostrtl)-(Obendl) to new block ending at (Nbendl) + +; Nbendl,Nbendh - new block end address (A/Y) +; Obendl,Obendh - old block end address +; Ostrtl,Ostrth - old block start address + +; returns with .. + +; Nbendl,Nbendh - new block start address (high byte - $100) +; Obendl,Obendh - old block start address (high byte - $100) +; Ostrtl,Ostrth - old block start address (unchanged) + +LAB_11CF + JSR LAB_121F ; check available memory, "Out of memory" error if no room + ; addr to check is in AY (low/high) + STA Earryl ; save new array mem end low byte + STY Earryh ; save new array mem end high byte + +; open up space in memory +; move (Ostrtl)-(Obendl) to new block ending at (Nbendl) +; don't set array end + +LAB_11D6 + SEC ; set carry for subtract + LDA Obendl ; get block end low byte + SBC Ostrtl ; subtract block start low byte + TAY ; copy MOD(block length/$100) byte to Y + LDA Obendh ; get block end high byte + SBC Ostrth ; subtract block start high byte + TAX ; copy block length high byte to X + INX ; +1 to allow for count=0 exit + TYA ; copy block length low byte to A + BEQ LAB_120A ; branch if length low byte=0 + + ; block is (X-1)*256+Y bytes, do the Y bytes first + + SEC ; set carry for add + 1, two's complement + EOR #$FF ; invert low byte for subtract + ADC Obendl ; add block end low byte + + STA Obendl ; save corrected old block end low byte + BCS LAB_11F3 ; branch if no underflow + + DEC Obendh ; else decrement block end high byte + SEC ; set carry for add + 1, two's complement +LAB_11F3 + TYA ; get MOD(block length/$100) byte + EOR #$FF ; invert low byte for subtract + ADC Nbendl ; add destination end low byte + STA Nbendl ; save modified new block end low byte + BCS LAB_1203 ; branch if no underflow + + DEC Nbendh ; else decrement block end high byte + BCC LAB_1203 ; branch always + +LAB_11FF + LDA (Obendl),Y ; get byte from source + STA (Nbendl),Y ; copy byte to destination +LAB_1203 + DEY ; decrement index + BNE LAB_11FF ; loop until Y=0 + + ; now do Y=0 indexed byte + LDA (Obendl),Y ; get byte from source + STA (Nbendl),Y ; save byte to destination +LAB_120A + DEC Obendh ; decrement source pointer high byte + DEC Nbendh ; decrement destination pointer high byte + DEX ; decrement block count + BNE LAB_1203 ; loop until count = $0 + + RTS + +; check room on stack for A bytes +; stack too deep? do OM error + +LAB_1212 + STA TempB ; save result in temp byte + TSX ; copy stack + CPX TempB ; compare new "limit" with stack + BCC LAB_OMER ; if stack < limit do "Out of memory" error then warm start + + RTS + +; check available memory, "Out of memory" error if no room +; addr to check is in AY (low/high) + +LAB_121F + CPY Sstorh ; compare bottom of string mem high byte + BCC LAB_124B ; if less then exit (is ok) + + BNE LAB_1229 ; skip next test if greater (tested <) + + ; high byte was =, now do low byte + CMP Sstorl ; compare with bottom of string mem low byte + BCC LAB_124B ; if less then exit (is ok) + + ; addr is > string storage ptr (oops!) +LAB_1229 + PHA ; push addr low byte + LDX #$08 ; set index to save Adatal to expneg inclusive + TYA ; copy addr high byte (to push on stack) + + ; save misc numeric work area +LAB_122D + PHA ; push byte + LDA Adatal-1,X ; get byte from Adatal to expneg ( ,$00 not pushed) + DEX ; decrement index + BPL LAB_122D ; loop until all done + + JSR LAB_GARB ; garbage collection routine + + ; restore misc numeric work area + LDX #$00 ; clear the index to restore bytes +LAB_1238 + PLA ; pop byte + STA Adatal,X ; save byte to Adatal to expneg + INX ; increment index + CPX #$08 ; compare with end + 1 + BMI LAB_1238 ; loop if more to do + + PLA ; pop addr high byte + TAY ; copy back to Y + PLA ; pop addr low byte + CPY Sstorh ; compare bottom of string mem high byte + BCC LAB_124B ; if less then exit (is ok) + + BNE LAB_OMER ; if greater do "Out of memory" error then warm start + + ; high byte was =, now do low byte + CMP Sstorl ; compare with bottom of string mem low byte + BCS LAB_OMER ; if >= do "Out of memory" error then warm start + + ; ok exit, carry clear +LAB_124B + RTS + +; do "Out of memory" error then warm start + +LAB_OMER + LDX #$0C ; error code $0C ("Out of memory" error) + +; do error #X, then warm start + +LAB_XERR + JSR LAB_CRLF ; print CR/LF + + LDA LAB_BAER,X ; get error message pointer low byte + LDY LAB_BAER+1,X ; get error message pointer high byte + JSR LAB_18C3 ; print null terminated string from memory + + JSR LAB_1491 ; flush stack and clear continue flag + LDA #LAB_EMSG ; point to " Error" high addr +LAB_1269 + JSR LAB_18C3 ; print null terminated string from memory + LDY Clineh ; get current line high byte + INY ; increment it + BEQ LAB_1274 ; go do warm start (was immediate mode) + + ; else print line number + JSR LAB_2953 ; print " in line [LINE #]" + +; BASIC warm start entry point +; wait for Basic command + +LAB_1274 + ; clear ON IRQ/NMI bytes + LDA #$00 ; clear A + STA IrqBase ; clear enabled byte + STA NmiBase ; clear enabled byte + LDA #LAB_RMSG ; point to "Ready" message high byte + + JSR LAB_18C3 ; go do print string + +; wait for Basic command (no "Ready") + +LAB_127D + JSR LAB_1357 ; call for BASIC input +LAB_1280 + STX Bpntrl ; set BASIC execute pointer low byte + STY Bpntrh ; set BASIC execute pointer high byte + JSR LAB_GBYT ; scan memory + BEQ LAB_127D ; loop while null + +; got to interpret input line now .. + + LDX #$FF ; current line to null value + STX Clineh ; set current line high byte + BCC LAB_1295 ; branch if numeric character (handle new BASIC line) + + ; no line number .. immediate mode + JSR LAB_13A6 ; crunch keywords into Basic tokens + JMP LAB_15F6 ; go scan and interpret code + +; handle new BASIC line + +LAB_1295 + JSR LAB_GFPN ; get fixed-point number into temp integer + JSR LAB_13A6 ; crunch keywords into Basic tokens + STY Ibptr ; save index pointer to end of crunched line + JSR LAB_SSLN ; search BASIC for temp integer line number + BCC LAB_12E6 ; branch if not found + + ; aroooogah! line # already exists! delete it + LDY #$01 ; set index to next line pointer high byte + LDA (Baslnl),Y ; get next line pointer high byte + STA ut1_ph ; save it + LDA Svarl ; get start of vars low byte + STA ut1_pl ; save it + LDA Baslnh ; get found line pointer high byte + STA ut2_ph ; save it + LDA Baslnl ; get found line pointer low byte + DEY ; decrement index + SBC (Baslnl),Y ; subtract next line pointer low byte + CLC ; clear carry for add + ADC Svarl ; add start of vars low byte + STA Svarl ; save new start of vars low byte + STA ut2_pl ; save destination pointer low byte + LDA Svarh ; get start of vars high byte + ADC #$FF ; -1 + carry + STA Svarh ; save start of vars high byte + SBC Baslnh ; subtract found line pointer high byte + TAX ; copy to block count + SEC ; set carry for subtract + LDA Baslnl ; get found line pointer low byte + SBC Svarl ; subtract start of vars low byte + TAY ; copy to bytes in first block count + BCS LAB_12D0 ; branch if overflow + + INX ; increment block count (correct for =0 loop exit) + DEC ut2_ph ; decrement destination high byte +LAB_12D0 + CLC ; clear carry for add + ADC ut1_pl ; add source pointer low byte + BCC LAB_12D8 ; branch if no overflow + + DEC ut1_ph ; else decrement source pointer high byte + CLC ; clear carry + + ; close up memory to delete old line +LAB_12D8 + LDA (ut1_pl),Y ; get byte from source + STA (ut2_pl),Y ; copy to destination + INY ; increment index + BNE LAB_12D8 ; while <> 0 do this block + + INC ut1_ph ; increment source pointer high byte + INC ut2_ph ; increment destination pointer high byte + DEX ; decrement block count + BNE LAB_12D8 ; loop until all done + + ; got new line in buffer and no existing same # +LAB_12E6 + LDA Ibuffs ; get byte from start of input buffer + BEQ LAB_1319 ; if null line just go flush stack/vars and exit + + ; got new line and it isn't empty line + LDA Ememl ; get end of mem low byte + LDY Ememh ; get end of mem high byte + STA Sstorl ; set bottom of string space low byte + STY Sstorh ; set bottom of string space high byte + LDA Svarl ; get start of vars low byte (end of BASIC) + STA Obendl ; save old block end low byte + LDY Svarh ; get start of vars high byte (end of BASIC) + STY Obendh ; save old block end high byte + ADC Ibptr ; add input buffer pointer (also buffer length) + BCC LAB_1301 ; branch if no overflow from add + + INY ; else increment high byte +LAB_1301 + STA Nbendl ; save new block end low byte (move to, low byte) + STY Nbendh ; save new block end high byte + JSR LAB_11CF ; open up space in memory + ; old start pointer Ostrtl,Ostrth set by the find line call + LDA Earryl ; get array mem end low byte + LDY Earryh ; get array mem end high byte + STA Svarl ; save start of vars low byte + STY Svarh ; save start of vars high byte + LDY Ibptr ; get input buffer pointer (also buffer length) + DEY ; adjust for loop type +LAB_1311 + LDA Ibuffs-4,Y ; get byte from crunched line + STA (Baslnl),Y ; save it to program memory + DEY ; decrement count + CPY #$03 ; compare with first byte-1 + BNE LAB_1311 ; continue while count <> 3 + + LDA Itemph ; get line # high byte + STA (Baslnl),Y ; save it to program memory + DEY ; decrement count + LDA Itempl ; get line # low byte + STA (Baslnl),Y ; save it to program memory + DEY ; decrement count + LDA #$FF ; set byte to allow chain rebuild. if you didn't set this + ; byte then a zero already here would stop the chain rebuild + ; as it would think it was the [EOT] marker. + STA (Baslnl),Y ; save it to program memory + +LAB_1319 + JSR LAB_1477 ; reset execution to start, clear vars and flush stack + LDX Smeml ; get start of mem low byte + LDA Smemh ; get start of mem high byte + LDY #$01 ; index to high byte of next line pointer +LAB_1325 + STX ut1_pl ; set line start pointer low byte + STA ut1_ph ; set line start pointer high byte + LDA (ut1_pl),Y ; get it + BEQ LAB_133E ; exit if end of program + +; rebuild chaining of Basic lines + + LDY #$04 ; point to first code byte of line + ; there is always 1 byte + [EOL] as null entries are deleted +LAB_1330 + INY ; next code byte + LDA (ut1_pl),Y ; get byte + BNE LAB_1330 ; loop if not [EOL] + + SEC ; set carry for add + 1 + TYA ; copy end index + ADC ut1_pl ; add to line start pointer low byte + TAX ; copy to X + LDY #$00 ; clear index, point to this line's next line pointer + STA (ut1_pl),Y ; set next line pointer low byte + TYA ; clear A + ADC ut1_ph ; add line start pointer high byte + carry + INY ; increment index to high byte + STA (ut1_pl),Y ; save next line pointer low byte + BCC LAB_1325 ; go do next line, branch always, carry clear + + +LAB_133E + JMP LAB_127D ; else we just wait for Basic command, no "Ready" + +; print "? " and get BASIC input + +LAB_INLN + JSR LAB_18E3 ; print "?" character + JSR LAB_18E0 ; print " " + BNE LAB_1357 ; call for BASIC input and return + +; receive line from keyboard + + ; $08 as delete key (BACKSPACE on standard keyboard) +LAB_134B + JSR LAB_PRNA ; go print the character + DEX ; decrement the buffer counter (delete) + .byte $2C ; make LDX into BIT abs + +; call for BASIC input (main entry point) + +LAB_1357 + LDX #$00 ; clear BASIC line buffer pointer +LAB_1359 + JSR V_INPT ; call scan input device + BCC LAB_1359 ; loop if no byte + + BEQ LAB_1359 ; loop until valid input (ignore NULLs) + + CMP #$07 ; compare with [BELL] + BEQ LAB_1378 ; branch if [BELL] + + CMP #$0D ; compare with [CR] + BEQ LAB_1384 ; do CR/LF exit if [CR] + + CPX #$00 ; compare pointer with $00 + BNE LAB_1374 ; branch if not empty + +; next two lines ignore any non print character and [SPACE] if input buffer empty + + CMP #$21 ; compare with [SP]+1 + BCC LAB_1359 ; if < ignore character + +LAB_1374 + CMP #$08 ; compare with [BACKSPACE] (delete last character) + BEQ LAB_134B ; go delete last character + +LAB_1378 + CPX #Ibuffe-Ibuffs ; compare character count with max + BCS LAB_138E ; skip store and do [BELL] if buffer full + + STA Ibuffs,X ; else store in buffer + INX ; increment pointer +LAB_137F + JSR LAB_PRNA ; go print the character + BNE LAB_1359 ; always loop for next character + +LAB_1384 + JMP LAB_1866 ; do CR/LF exit to BASIC + +; announce buffer full + +LAB_138E + LDA #$07 ; [BELL] character into A + BNE LAB_137F ; go print the [BELL] but ignore input character + ; branch always + +; crunch keywords into Basic tokens +; position independent buffer version .. +; faster, dictionary search version .... + +LAB_13A6 + LDY #$FF ; set save index (makes for easy math later) + + SEC ; set carry for subtract + LDA Bpntrl ; get basic execute pointer low byte + SBC #= go save byte then continue crunching + + CMP #'<' ; compare with "<" + BCS LAB_13CC ; if >= go crunch now + + CMP #'0' ; compare with "0" + BCS LAB_13EC ; if >= go save byte then continue crunching + + STA Scnquo ; save buffer byte as search character + CMP #$22 ; is it quote character? + BEQ LAB_1410 ; branch if so (copy quoted string) + + CMP #'*' ; compare with "*" + BCC LAB_13EC ; if < go save byte then continue crunching + + ; else crunch now +LAB_13CC + BIT Oquote ; get open quote/DATA token flag + BVS LAB_13EC ; branch if b6 of Oquote set (was DATA) + ; go save byte then continue crunching + + STX TempB ; save buffer read index + STY csidx ; copy buffer save index + LDY #TAB_1STC ; get keyword first character table high address + STY ut2_ph ; save pointer high byte + LDY #$00 ; clear table pointer + +LAB_13D0 + CMP (ut2_pl),Y ; compare with keyword first character table byte + BEQ LAB_13D1 ; go do word_table_chr if match + + BCC LAB_13EA ; if < keyword first character table byte go restore + ; Y and save to crunched + + INY ; else increment pointer + BNE LAB_13D0 ; and loop (branch always) + +; have matched first character of some keyword + +LAB_13D1 + TYA ; copy matching index + ASL ; *2 (bytes per pointer) + TAX ; copy to new index + LDA TAB_CHRT,X ; get keyword table pointer low byte + STA ut2_pl ; save pointer low byte + LDA TAB_CHRT+1,X ; get keyword table pointer high byte + STA ut2_ph ; save pointer high byte + + LDY #$FF ; clear table pointer (make -1 for start) + + LDX TempB ; restore buffer read index + +LAB_13D6 + INY ; next table byte + LDA (ut2_pl),Y ; get byte from table +LAB_13D8 + BMI LAB_13EA ; all bytes matched so go save token + + INX ; next buffer byte + CMP Ibuffs,X ; compare with byte from input buffer + BEQ LAB_13D6 ; go compare next if match + + BNE LAB_1417 ; branch if >< (not found keyword) + +LAB_13EA + LDY csidx ; restore save index + + ; save crunched to output +LAB_13EC + INX ; increment buffer index (to next input byte) + INY ; increment save index (to next output byte) + STA Ibuffs,Y ; save byte to output + CMP #$00 ; set the flags, set carry + BEQ LAB_142A ; do exit if was null [EOL] + + ; A holds token or byte here + SBC #':' ; subtract ":" (carry set by CMP #00) + BEQ LAB_13FF ; branch if it was ":" (is now $00) + + ; A now holds token-$3A + CMP #TK_DATA-$3A ; compare with DATA token - $3A + BNE LAB_1401 ; branch if not DATA + + ; token was : or DATA +LAB_13FF + STA Oquote ; save token-$3A (clear for ":", TK_DATA-$3A for DATA) +LAB_1401 + EOR #TK_REM-$3A ; effectively subtract REM token offset + BNE LAB_13AC ; If wasn't REM then go crunch rest of line + + STA Asrch ; else was REM so set search for [EOL] + + ; loop for REM, "..." etc. +LAB_1408 + LDA Ibuffs,X ; get byte from input buffer + BEQ LAB_13EC ; branch if null [EOL] + + CMP Asrch ; compare with stored character + BEQ LAB_13EC ; branch if match (end quote) + + ; entry for copy string in quotes, don't crunch +LAB_1410 + INY ; increment buffer save index + STA Ibuffs,Y ; save byte to output + INX ; increment buffer read index + BNE LAB_1408 ; loop while <> 0 (should never be 0!) + + ; not found keyword this go +LAB_1417 + LDX TempB ; compare has failed, restore buffer index (start byte!) + + ; now find the end of this word in the table +LAB_141B + LDA (ut2_pl),Y ; get table byte + PHP ; save status + INY ; increment table index + PLP ; restore byte status + BPL LAB_141B ; if not end of keyword go do next + + LDA (ut2_pl),Y ; get byte from keyword table + BNE LAB_13D8 ; go test next word if not zero byte (end of table) + + ; reached end of table with no match + LDA Ibuffs,X ; restore byte from input buffer + BPL LAB_13EA ; branch always (all bytes in buffer are $00-$7F) + ; go save byte in output and continue crunching + + ; reached [EOL] +LAB_142A + INY ; increment pointer + INY ; increment pointer (makes it next line pointer high byte) + STA Ibuffs,Y ; save [EOL] (marks [EOT] in immediate mode) + INY ; adjust for line copy + INY ; adjust for line copy + INY ; adjust for line copy + DEC Bpntrl ; allow for increment (change if buffer starts at $xxFF) + RTS + +; search Basic for temp integer line number from start of mem + +LAB_SSLN + LDA Smeml ; get start of mem low byte + LDX Smemh ; get start of mem high byte + +; search Basic for temp integer line number from AX +; returns carry set if found +; returns Baslnl/Baslnh pointer to found or next higher (not found) line + +; old 541 new 507 + +LAB_SHLN + LDY #$01 ; set index + STA Baslnl ; save low byte as current + STX Baslnh ; save high byte as current + LDA (Baslnl),Y ; get pointer high byte from addr + BEQ LAB_145F ; pointer was zero so we're done, do 'not found' exit + + LDY #$03 ; set index to line # high byte + LDA (Baslnl),Y ; get line # high byte + DEY ; decrement index (point to low byte) + CMP Itemph ; compare with temporary integer high byte + BNE LAB_1455 ; if <> skip low byte check + + LDA (Baslnl),Y ; get line # low byte + CMP Itempl ; compare with temporary integer low byte +LAB_1455 + BCS LAB_145E ; else if temp < this line, exit (passed line#) + +LAB_1456 + DEY ; decrement index to next line ptr high byte + LDA (Baslnl),Y ; get next line pointer high byte + TAX ; copy to X + DEY ; decrement index to next line ptr low byte + LDA (Baslnl),Y ; get next line pointer low byte + BCC LAB_SHLN ; go search for line # in temp (Itempl/Itemph) from AX + ; (carry always clear) + +LAB_145E + BEQ LAB_1460 ; exit if temp = found line #, carry is set + +LAB_145F + CLC ; clear found flag +LAB_1460 + RTS + +; perform NEW + +LAB_NEW + BNE LAB_1460 ; exit if not end of statement (to do syntax error) + +LAB_1463 + LDA #$00 ; clear A + TAY ; clear Y + STA (Smeml),Y ; clear first line, next line pointer, low byte + INY ; increment index + STA (Smeml),Y ; clear first line, next line pointer, high byte + CLC ; clear carry + LDA Smeml ; get start of mem low byte + ADC #$02 ; calculate end of BASIC low byte + STA Svarl ; save start of vars low byte + LDA Smemh ; get start of mem high byte + ADC #$00 ; add any carry + STA Svarh ; save start of vars high byte + +; reset execution to start, clear vars and flush stack + +LAB_1477 + CLC ; clear carry + LDA Smeml ; get start of mem low byte + ADC #$FF ; -1 + STA Bpntrl ; save BASIC execute pointer low byte + LDA Smemh ; get start of mem high byte + ADC #$FF ; -1+carry + STA Bpntrh ; save BASIC execute pointer high byte + +; "CLEAR" command gets here + +LAB_147A + LDA Ememl ; get end of mem low byte + LDY Ememh ; get end of mem high byte + STA Sstorl ; set bottom of string space low byte + STY Sstorh ; set bottom of string space high byte + LDA Svarl ; get start of vars low byte + LDY Svarh ; get start of vars high byte + STA Sarryl ; save var mem end low byte + STY Sarryh ; save var mem end high byte + STA Earryl ; save array mem end low byte + STY Earryh ; save array mem end high byte + JSR LAB_161A ; perform RESTORE command + +; flush stack and clear continue flag + +LAB_1491 + LDX #des_sk ; set descriptor stack pointer + STX next_s ; save descriptor stack pointer + PLA ; pull return address low byte + TAX ; copy return address low byte + PLA ; pull return address high byte + STX LAB_SKFE ; save to cleared stack + STA LAB_SKFF ; save to cleared stack + LDX #$FD ; new stack pointer + TXS ; reset stack + LDA #$00 ; clear byte + STA Cpntrh ; clear continue pointer high byte + STA Sufnxf ; clear subscript/FNX flag +LAB_14A6 + RTS + +; perform CLEAR + +LAB_CLEAR + BEQ LAB_147A ; if no following token go do "CLEAR" + + ; else there was a following token (go do syntax error) + RTS + +; perform LIST [n][-m] +; bigger, faster version (a _lot_ faster) + +LAB_LIST + BCC LAB_14BD ; branch if next character numeric (LIST n..) + + BEQ LAB_14BD ; branch if next character [NULL] (LIST) + + CMP #TK_MINUS ; compare with token for - + BNE LAB_14A6 ; exit if not - (LIST -m) + + ; LIST [[n][-m]] + ; this bit sets the n , if present, as the start and end +LAB_14BD + JSR LAB_GFPN ; get fixed-point number into temp integer + JSR LAB_SSLN ; search BASIC for temp integer line number + ; (pointer in Baslnl/Baslnh) + JSR LAB_GBYT ; scan memory + BEQ LAB_14D4 ; branch if no more characters + + ; this bit checks the - is present + CMP #TK_MINUS ; compare with token for - + BNE LAB_1460 ; return if not "-" (will be Syntax error) + + ; LIST [n]-m + ; the - was there so set m as the end value + JSR LAB_IGBY ; increment and scan memory + JSR LAB_GFPN ; get fixed-point number into temp integer + BNE LAB_1460 ; exit if not ok + +LAB_14D4 + LDA Itempl ; get temporary integer low byte + ORA Itemph ; OR temporary integer high byte + BNE LAB_14E2 ; branch if start set + + LDA #$FF ; set for -1 + STA Itempl ; set temporary integer low byte + STA Itemph ; set temporary integer high byte +LAB_14E2 + LDY #$01 ; set index for line + STY Oquote ; clear open quote flag + JSR LAB_CRLF ; print CR/LF + LDA (Baslnl),Y ; get next line pointer high byte + ; pointer initially set by search at LAB_14BD + BEQ LAB_152B ; if null all done so exit + JSR LAB_1629 ; do CRTL-C check vector + + INY ; increment index for line + LDA (Baslnl),Y ; get line # low byte + TAX ; copy to X + INY ; increment index + LDA (Baslnl),Y ; get line # high byte + CMP Itemph ; compare with temporary integer high byte + BNE LAB_14FF ; branch if no high byte match + + CPX Itempl ; compare with temporary integer low byte + BEQ LAB_1501 ; branch if = last line to do (< will pass next branch) + +LAB_14FF ; else .. + BCS LAB_152B ; if greater all done so exit + +LAB_1501 + STY Tidx1 ; save index for line + JSR LAB_295E ; print XA as unsigned integer + LDA #$20 ; space is the next character +LAB_1508 + LDY Tidx1 ; get index for line + AND #$7F ; mask top out bit of character +LAB_150C + JSR LAB_PRNA ; go print the character + CMP #$22 ; was it " character + BNE LAB_1519 ; branch if not + + ; we are either entering or leaving a pair of quotes + LDA Oquote ; get open quote flag + EOR #$FF ; toggle it + STA Oquote ; save it back +LAB_1519 + INY ; increment index + LDA (Baslnl),Y ; get next byte + BNE LAB_152E ; branch if not [EOL] (go print character) + TAY ; else clear index + LDA (Baslnl),Y ; get next line pointer low byte + TAX ; copy to X + INY ; increment index + LDA (Baslnl),Y ; get next line pointer high byte + STX Baslnl ; set pointer to line low byte + STA Baslnh ; set pointer to line high byte + BNE LAB_14E2 ; go do next line if not [EOT] + ; else .. +LAB_152B + RTS + +LAB_152E + BPL LAB_150C ; just go print it if not token byte + + ; else was token byte so uncrunch it (maybe) + BIT Oquote ; test the open quote flag + BMI LAB_150C ; just go print character if open quote set + + LDX #>LAB_KEYT ; get table address high byte + ASL ; *2 + ASL ; *4 + BCC LAB_152F ; branch if no carry + + INX ; else increment high byte + CLC ; clear carry for add +LAB_152F + ADC #LAB_159F ; set return address high byte + STA ut1_pl ; save return address low byte + STY ut1_ph ; save return address high byte + JMP LAB_1B66 ; round FAC1 and put on stack (returns to next instruction) + +LAB_159F + LDA #LAB_259C ; set 1 pointer high addr + JSR LAB_UFAC ; unpack memory (AY) into FAC1 + JSR LAB_GBYT ; scan memory + CMP #TK_STEP ; compare with STEP token + BNE LAB_15B3 ; jump if not "STEP" + + ;.was step so .. + JSR LAB_IGBY ; increment and scan memory + JSR LAB_EVNM ; evaluate expression and check is numeric, + ; else do type mismatch +LAB_15B3 + JSR LAB_27CA ; return A=FF,C=1/-ve A=01,C=0/+ve + STA FAC1_s ; set FAC1 sign (b7) + ; this is +1 for +ve step and -1 for -ve step, in NEXT we + ; compare the FOR value and the TO value and return +1 if + ; FOR > TO, 0 if FOR = TO and -1 if FOR < TO. the value + ; here (+/-1) is then compared to that result and if they + ; are the same (+ve and FOR > TO or -ve and FOR < TO) then + ; the loop is done + JSR LAB_1B5B ; push sign, round FAC1 and put on stack + LDA Frnxth ; get var pointer for FOR/NEXT high byte + PHA ; push on stack + LDA Frnxtl ; get var pointer for FOR/NEXT low byte + PHA ; push on stack + LDA #TK_FOR ; get FOR token + PHA ; push on stack + +; interpreter inner loop + +LAB_15C2 + JSR LAB_1629 ; do CRTL-C check vector + LDA Bpntrl ; get BASIC execute pointer low byte + LDY Bpntrh ; get BASIC execute pointer high byte + + LDX Clineh ; continue line is $FFxx for immediate mode + ; ($00xx for RUN from immediate mode) + INX ; increment it (now $00 if immediate mode) + BEQ LAB_15D1 ; branch if null (immediate mode) + + STA Cpntrl ; save continue pointer low byte + STY Cpntrh ; save continue pointer high byte +LAB_15D1 + LDY #$00 ; clear index + LDA (Bpntrl),Y ; get next byte + BEQ LAB_15DC ; branch if null [EOL] + + CMP #':' ; compare with ":" + BEQ LAB_15F6 ; branch if = (statement separator) + +LAB_15D9 + JMP LAB_SNER ; else syntax error then warm start + + ; have reached [EOL] +LAB_15DC + LDY #$02 ; set index + LDA (Bpntrl),Y ; get next line pointer high byte + CLC ; clear carry for no "BREAK" message + BEQ LAB_1651 ; if null go to immediate mode (was immediate or [EOT] + ; marker) + + INY ; increment index + LDA (Bpntrl),Y ; get line # low byte + STA Clinel ; save current line low byte + INY ; increment index + LDA (Bpntrl),Y ; get line # high byte + STA Clineh ; save current line high byte + TYA ; A now = 4 + ADC Bpntrl ; add BASIC execute pointer low byte + STA Bpntrl ; save BASIC execute pointer low byte + BCC LAB_15F6 ; branch if no overflow + + INC Bpntrh ; else increment BASIC execute pointer high byte +LAB_15F6 + JSR LAB_IGBY ; increment and scan memory + +LAB_15F9 + JSR LAB_15FF ; go interpret BASIC code from (Bpntrl) + +LAB_15FC + JMP LAB_15C2 ; loop + +; interpret BASIC code from (Bpntrl) + +LAB_15FF + BEQ LAB_1628 ; exit if zero [EOL] + +LAB_1602 + ASL ; *2 bytes per vector and normalise token + BCS LAB_1609 ; branch if was token + + JMP LAB_LET ; else go do implied LET + +LAB_1609 + CMP #[TK_TAB-$80]*2 ; compare normalised token * 2 with TAB + BCS LAB_15D9 ; branch if A>=TAB (do syntax error then warm start) + ; only tokens before TAB can start a line + TAY ; copy to index + LDA LAB_CTBL+1,Y ; get vector high byte + PHA ; onto stack + LDA LAB_CTBL,Y ; get vector low byte + PHA ; onto stack + JMP LAB_IGBY ; jump to increment and scan memory + ; then "return" to vector + +; CTRL-C check jump. this is called as a subroutine but exits back via a jump if a +; key press is detected. + +LAB_1629 + JMP (VEC_CC) ; ctrl c check vector + +; if there was a key press it gets back here .. + +LAB_1636 + CMP #$03 ; compare with CTRL-C + +; perform STOP + +LAB_STOP + BCS LAB_163B ; branch if token follows STOP + ; else just END +; END + +LAB_END + CLC ; clear the carry, indicate a normal program end +LAB_163B + BNE LAB_167A ; if wasn't CTRL-C or there is a following byte return + + LDA Bpntrh ; get the BASIC execute pointer high byte + EOR #>Ibuffs ; compare with buffer address high byte (Cb unchanged) + BEQ LAB_164F ; branch if the BASIC pointer is in the input buffer + ; (can't continue in immediate mode) + + ; else .. + EOR #>Ibuffs ; correct the bits + LDY Bpntrl ; get BASIC execute pointer low byte + STY Cpntrl ; save continue pointer low byte + STA Cpntrh ; save continue pointer high byte +LAB_1647 + LDA Clinel ; get current line low byte + LDY Clineh ; get current line high byte + STA Blinel ; save break line low byte + STY Blineh ; save break line high byte +LAB_164F + PLA ; pull return address low + PLA ; pull return address high +LAB_1651 + BCC LAB_165E ; if was program end just do warm start + + ; else .. + LDA #LAB_BMSG ; point to "Break" high byte + JMP LAB_1269 ; print "Break" and do warm start + +LAB_165E + JMP LAB_1274 ; go do warm start + +; perform RESTORE + +LAB_RESTORE + BNE LAB_RESTOREn ; branch if next character not null (RESTORE n) + +LAB_161A + SEC ; set carry for subtract + LDA Smeml ; get start of mem low byte + SBC #$01 ; -1 + LDY Smemh ; get start of mem high byte + BCS LAB_1624 ; branch if no underflow + +LAB_uflow + DEY ; else decrement high byte +LAB_1624 + STA Dptrl ; save DATA pointer low byte + STY Dptrh ; save DATA pointer high byte +LAB_1628 + RTS + + ; is RESTORE n +LAB_RESTOREn + JSR LAB_GFPN ; get fixed-point number into temp integer + JSR LAB_SNBL ; scan for next BASIC line + LDA Clineh ; get current line high byte + CMP Itemph ; compare with temporary integer high byte + BCS LAB_reset_search ; branch if >= (start search from beginning) + + TYA ; else copy line index to A + SEC ; set carry (+1) + ADC Bpntrl ; add BASIC execute pointer low byte + LDX Bpntrh ; get BASIC execute pointer high byte + BCC LAB_go_search ; branch if no overflow to high byte + + INX ; increment high byte + BCS LAB_go_search ; branch always (can never be carry clear) + +; search for line # in temp (Itempl/Itemph) from start of mem pointer (Smeml) + +LAB_reset_search + LDA Smeml ; get start of mem low byte + LDX Smemh ; get start of mem high byte + +; search for line # in temp (Itempl/Itemph) from (AX) + +LAB_go_search + + JSR LAB_SHLN ; search Basic for temp integer line number from AX + BCS LAB_line_found ; if carry set go set pointer + + JMP LAB_16F7 ; else go do "Undefined statement" error + +LAB_line_found + ; carry already set for subtract + LDA Baslnl ; get pointer low byte + SBC #$01 ; -1 + LDY Baslnh ; get pointer high byte + BCS LAB_1624 ; branch if no underflow (save DATA pointer and return) + + BCC LAB_uflow ; else decrement high byte then save DATA pointer and + ; return (branch always) + +; perform NULL + +LAB_NULL + JSR LAB_GTBY ; get byte parameter + STX Nullct ; save new NULL count +LAB_167A + RTS + +; perform CONT + +LAB_CONT + BNE LAB_167A ; if following byte exit to do syntax error + + LDY Cpntrh ; get continue pointer high byte + BNE LAB_166C ; go do continue if we can + + LDX #$1E ; error code $1E ("Can't continue" error) + JMP LAB_XERR ; do error #X, then warm start + + ; we can continue so .. +LAB_166C + LDA #TK_ON ; set token for ON + JSR LAB_IRQ ; set IRQ flags + LDA #TK_ON ; set token for ON + JSR LAB_NMI ; set NMI flags + + STY Bpntrh ; save BASIC execute pointer high byte + LDA Cpntrl ; get continue pointer low byte + STA Bpntrl ; save BASIC execute pointer low byte + LDA Blinel ; get break line low byte + LDY Blineh ; get break line high byte + STA Clinel ; set current line low byte + STY Clineh ; set current line high byte + RTS + +; perform RUN + +LAB_RUN + BNE LAB_1696 ; branch if RUN n + JMP LAB_1477 ; reset execution to start, clear variables, flush stack and + ; return + +; does RUN n + +LAB_1696 + JSR LAB_147A ; go do "CLEAR" + BEQ LAB_16B0 ; get n and do GOTO n (branch always as CLEAR sets Z=1) + +; perform DO + +LAB_DO + LDA #$05 ; need 5 bytes for DO + JSR LAB_1212 ; check room on stack for A bytes + LDA Bpntrh ; get BASIC execute pointer high byte + PHA ; push on stack + LDA Bpntrl ; get BASIC execute pointer low byte + PHA ; push on stack + LDA Clineh ; get current line high byte + PHA ; push on stack + LDA Clinel ; get current line low byte + PHA ; push on stack + LDA #TK_DO ; token for DO + PHA ; push on stack + JSR LAB_GBYT ; scan memory + JMP LAB_15C2 ; go do interpreter inner loop + +; perform GOSUB + +LAB_GOSUB + LDA #$05 ; need 5 bytes for GOSUB + JSR LAB_1212 ; check room on stack for A bytes + LDA Bpntrh ; get BASIC execute pointer high byte + PHA ; push on stack + LDA Bpntrl ; get BASIC execute pointer low byte + PHA ; push on stack + LDA Clineh ; get current line high byte + PHA ; push on stack + LDA Clinel ; get current line low byte + PHA ; push on stack + LDA #TK_GOSUB ; token for GOSUB + PHA ; push on stack +LAB_16B0 + JSR LAB_GBYT ; scan memory + JSR LAB_GOTO ; perform GOTO n + JMP LAB_15C2 ; go do interpreter inner loop + ; (can't RTS, we used the stack!) + +; perform GOTO + +LAB_GOTO + JSR LAB_GFPN ; get fixed-point number into temp integer + JSR LAB_SNBL ; scan for next BASIC line + LDA Clineh ; get current line high byte + CMP Itemph ; compare with temporary integer high byte + BCS LAB_16D0 ; branch if >= (start search from beginning) + + TYA ; else copy line index to A + SEC ; set carry (+1) + ADC Bpntrl ; add BASIC execute pointer low byte + LDX Bpntrh ; get BASIC execute pointer high byte + BCC LAB_16D4 ; branch if no overflow to high byte + + INX ; increment high byte + BCS LAB_16D4 ; branch always (can never be carry) + +; search for line # in temp (Itempl/Itemph) from start of mem pointer (Smeml) + +LAB_16D0 + LDA Smeml ; get start of mem low byte + LDX Smemh ; get start of mem high byte + +; search for line # in temp (Itempl/Itemph) from (AX) + +LAB_16D4 + JSR LAB_SHLN ; search Basic for temp integer line number from AX + BCC LAB_16F7 ; if carry clear go do "Undefined statement" error + ; (unspecified statement) + + ; carry already set for subtract + LDA Baslnl ; get pointer low byte + SBC #$01 ; -1 + STA Bpntrl ; save BASIC execute pointer low byte + LDA Baslnh ; get pointer high byte + SBC #$00 ; subtract carry + STA Bpntrh ; save BASIC execute pointer high byte +LAB_16E5 + RTS + +LAB_DONOK + LDX #$22 ; error code $22 ("LOOP without DO" error) + JMP LAB_XERR ; do error #X, then warm start + +; perform LOOP + +LAB_LOOP + TAY ; save following token + TSX ; copy stack pointer + LDA LAB_STAK+3,X ; get token byte from stack + CMP #TK_DO ; compare with DO token + BNE LAB_DONOK ; branch if no matching DO + + INX ; dump calling routine return address + INX ; dump calling routine return address + TXS ; correct stack + TYA ; get saved following token back + BEQ LoopAlways ; if no following token loop forever + ; (stack pointer in X) + + CMP #':' ; could be ':' + BEQ LoopAlways ; if :... loop forever + + SBC #TK_UNTIL ; subtract token for UNTIL, we know carry is set here + TAX ; copy to X (if it was UNTIL then Y will be correct) + BEQ DoRest ; branch if was UNTIL + + DEX ; decrement result + BNE LAB_16FC ; if not WHILE go do syntax error and warm start + ; only if the token was WHILE will this fail + + DEX ; set invert result byte +DoRest + STX Frnxth ; save invert result byte + JSR LAB_IGBY ; increment and scan memory + JSR LAB_EVEX ; evaluate expression + LDA FAC1_e ; get FAC1 exponent + BEQ DoCmp ; if =0 go do straight compare + + LDA #$FF ; else set all bits +DoCmp + TSX ; copy stack pointer + EOR Frnxth ; EOR with invert byte + BNE LoopDone ; if <> 0 clear stack and back to interpreter loop + + ; loop condition wasn't met so do it again +LoopAlways + LDA LAB_STAK+2,X ; get current line low byte + STA Clinel ; save current line low byte + LDA LAB_STAK+3,X ; get current line high byte + STA Clineh ; save current line high byte + LDA LAB_STAK+4,X ; get BASIC execute pointer low byte + STA Bpntrl ; save BASIC execute pointer low byte + LDA LAB_STAK+5,X ; get BASIC execute pointer high byte + STA Bpntrh ; save BASIC execute pointer high byte + JSR LAB_GBYT ; scan memory + JMP LAB_15C2 ; go do interpreter inner loop + + ; clear stack and back to interpreter loop +LoopDone + INX ; dump DO token + INX ; dump current line low byte + INX ; dump current line high byte + INX ; dump BASIC execute pointer low byte + INX ; dump BASIC execute pointer high byte + TXS ; correct stack + JMP LAB_DATA ; go perform DATA (find : or [EOL]) + +; do the return without gosub error + +LAB_16F4 + LDX #$04 ; error code $04 ("RETURN without GOSUB" error) + .byte $2C ; makes next line BIT LAB_0EA2 + +LAB_16F7 ; do undefined statement error + LDX #$0E ; error code $0E ("Undefined statement" error) + JMP LAB_XERR ; do error #X, then warm start + +; perform RETURN + +LAB_RETURN + BNE LAB_16E5 ; exit if following token (to allow syntax error) + +LAB_16E8 + PLA ; dump calling routine return address + PLA ; dump calling routine return address + PLA ; pull token + CMP #TK_GOSUB ; compare with GOSUB token + BNE LAB_16F4 ; branch if no matching GOSUB + +LAB_16FF + PLA ; pull current line low byte + STA Clinel ; save current line low byte + PLA ; pull current line high byte + STA Clineh ; save current line high byte + PLA ; pull BASIC execute pointer low byte + STA Bpntrl ; save BASIC execute pointer low byte + PLA ; pull BASIC execute pointer high byte + STA Bpntrh ; save BASIC execute pointer high byte + + ; now do the DATA statement as we could be returning into + ; the middle of an ON GOSUB n,m,p,q line + ; (the return address used by the DATA statement is the one + ; pushed before the GOSUB was executed!) + +; perform DATA + +LAB_DATA + JSR LAB_SNBS ; scan for next BASIC statement ([:] or [EOL]) + + ; set BASIC execute pointer +LAB_170F + TYA ; copy index to A + CLC ; clear carry for add + ADC Bpntrl ; add BASIC execute pointer low byte + STA Bpntrl ; save BASIC execute pointer low byte + BCC LAB_1719 ; skip next if no carry + + INC Bpntrh ; else increment BASIC execute pointer high byte +LAB_1719 + RTS + +LAB_16FC + JMP LAB_SNER ; do syntax error then warm start + +; scan for next BASIC statement ([:] or [EOL]) +; returns Y as index to [:] or [EOL] + +LAB_SNBS + LDX #':' ; set look for character = ":" + .byte $2C ; makes next line BIT $00A2 + +; scan for next BASIC line +; returns Y as index to [EOL] + +LAB_SNBL + LDX #$00 ; set alt search character = [EOL] + LDY #$00 ; set search character = [EOL] + STY Asrch ; store search character +LAB_1725 + TXA ; get alt search character + EOR Asrch ; toggle search character, effectively swap with $00 + STA Asrch ; save swapped search character +LAB_172D + LDA (Bpntrl),Y ; get next byte + BEQ LAB_1719 ; exit if null [EOL] + + CMP Asrch ; compare with search character + BEQ LAB_1719 ; exit if found + + INY ; increment index + CMP #$22 ; compare current character with open quote + BNE LAB_172D ; if not open quote go get next character + + BEQ LAB_1725 ; if found go swap search character for alt search character + +; perform IF + +LAB_IF + JSR LAB_EVEX ; evaluate the expression + JSR LAB_GBYT ; scan memory + CMP #TK_THEN ; compare with THEN token + BEQ LAB_174B ; if it was THEN go do IF + + ; wasn't IF .. THEN so must be IF .. GOTO + CMP #TK_GOTO ; compare with GOTO token + BNE LAB_16FC ; if it wasn't GOTO go do syntax error + + LDX Bpntrl ; save the basic pointer low byte + LDY Bpntrh ; save the basic pointer high byte + JSR LAB_IGBY ; increment and scan memory + BCS LAB_16FC ; if not numeric go do syntax error + + STX Bpntrl ; restore the basic pointer low byte + STY Bpntrh ; restore the basic pointer high byte +LAB_174B + LDA FAC1_e ; get FAC1 exponent + BEQ LAB_174E ; if the result was zero go look for an ELSE + + JSR LAB_IGBY ; else increment and scan memory + BCS LAB_174D ; if not numeric go do var or keyword + +LAB_174C + JMP LAB_GOTO ; else was numeric so do GOTO n + + ; is var or keyword +LAB_174D + CMP #TK_RETURN ; compare the byte with the token for RETURN + BNE LAB_174G ; if it wasn't RETURN go interpret BASIC code from (Bpntrl) + ; and return to this code to process any following code + + JMP LAB_1602 ; else it was RETURN so interpret BASIC code from (Bpntrl) + ; but don't return here + +LAB_174G + JSR LAB_15FF ; interpret BASIC code from (Bpntrl) + +; the IF was executed and there may be a following ELSE so the code needs to return +; here to check and ignore the ELSE if present + + LDY #$00 ; clear the index + LDA (Bpntrl),Y ; get the next BASIC byte + CMP #TK_ELSE ; compare it with the token for ELSE + BEQ LAB_DATA ; if ELSE ignore the following statement + +; there was no ELSE so continue execution of IF THEN [: ]. any +; following ELSE will, correctly, cause a syntax error + + RTS ; else return to the interpreter inner loop + +; perform ELSE after IF + +LAB_174E + LDY #$00 ; clear the BASIC byte index + LDX #$01 ; clear the nesting depth +LAB_1750 + INY ; increment the BASIC byte index + LDA (Bpntrl),Y ; get the next BASIC byte + BEQ LAB_1753 ; if EOL go add the pointer and return + + CMP #TK_IF ; compare the byte with the token for IF + BNE LAB_1752 ; if not IF token skip the depth increment + + INX ; else increment the nesting depth .. + BNE LAB_1750 ; .. and continue looking + +LAB_1752 + CMP #TK_ELSE ; compare the byte with the token for ELSE + BNE LAB_1750 ; if not ELSE token continue looking + + DEX ; was ELSE so decrement the nesting depth + BNE LAB_1750 ; loop if still nested + + INY ; increment the BASIC byte index past the ELSE + +; found the matching ELSE, now do <{n|statement}> + +LAB_1753 + TYA ; else copy line index to A + CLC ; clear carry for add + ADC Bpntrl ; add the BASIC execute pointer low byte + STA Bpntrl ; save the BASIC execute pointer low byte + BCC LAB_1754 ; branch if no overflow to high byte + + INC Bpntrh ; else increment the BASIC execute pointer high byte +LAB_1754 + JSR LAB_GBYT ; scan memory + BCC LAB_174C ; if numeric do GOTO n + ; the code will return to the interpreter loop at the + ; tail end of the GOTO + + JMP LAB_15FF ; interpret BASIC code from (Bpntrl) + ; the code will return to the interpreter loop at the + ; tail end of the + +; perform REM, skip (rest of) line + +LAB_REM + JSR LAB_SNBL ; scan for next BASIC line + JMP LAB_170F ; go set BASIC execute pointer and return, branch always + +LAB_16FD + JMP LAB_SNER ; do syntax error then warm start + +; perform ON + +LAB_ON + CMP #TK_IRQ ; was it IRQ token ? + BNE LAB_NOIN ; if not go check NMI + + JMP LAB_SIRQ ; else go set-up IRQ + +LAB_NOIN + CMP #TK_NMI ; was it NMI token ? + BNE LAB_NONM ; if not go do normal ON command + + JMP LAB_SNMI ; else go set-up NMI + +LAB_NONM + JSR LAB_GTBY ; get byte parameter + PHA ; push GOTO/GOSUB token + CMP #TK_GOSUB ; compare with GOSUB token + BEQ LAB_176B ; branch if GOSUB + + CMP #TK_GOTO ; compare with GOTO token +LAB_1767 + BNE LAB_16FD ; if not GOTO do syntax error then warm start + + +; next character was GOTO or GOSUB + +LAB_176B + DEC FAC1_3 ; decrement index (byte value) + BNE LAB_1773 ; branch if not zero + + PLA ; pull GOTO/GOSUB token + JMP LAB_1602 ; go execute it + +LAB_1773 + JSR LAB_IGBY ; increment and scan memory + JSR LAB_GFPN ; get fixed-point number into temp integer (skip this n) + ; (we could LDX #',' and JSR LAB_SNBL+2, then we + ; just BNE LAB_176B for the loop. should be quicker .. + ; no we can't, what if we meet a colon or [EOL]?) + CMP #$2C ; compare next character with "," + BEQ LAB_176B ; loop if "," + +LAB_177E + PLA ; else pull keyword token (run out of options) + ; also dump +/-1 pointer low byte and exit +LAB_177F + RTS + +; takes n * 106 + 11 cycles where n is the number of digits + +; get fixed-point number into temp integer + +LAB_GFPN + LDX #$00 ; clear reg + STX Itempl ; clear temporary integer low byte +LAB_1785 + STX Itemph ; save temporary integer high byte + BCS LAB_177F ; return if carry set, end of scan, character was + ; not 0-9 + + CPX #$19 ; compare high byte with $19 + TAY ; ensure Zb = 0 if the branch is taken + BCS LAB_1767 ; branch if >=, makes max line # 63999 because next + ; bit does *$0A, = 64000, compare at target will fail + ; and do syntax error + + SBC #'0'-1 ; subtract "0", $2F + carry, from byte + TAY ; copy binary digit + LDA Itempl ; get temporary integer low byte + ASL ; *2 low byte + ROL Itemph ; *2 high byte + ASL ; *2 low byte + ROL Itemph ; *2 high byte, *4 + ADC Itempl ; + low byte, *5 + STA Itempl ; save it + TXA ; get high byte copy to A + ADC Itemph ; + high byte, *5 + ASL Itempl ; *2 low byte, *10d + ROL ; *2 high byte, *10d + TAX ; copy high byte back to X + TYA ; get binary digit back + ADC Itempl ; add number low byte + STA Itempl ; save number low byte + BCC LAB_17B3 ; if no overflow to high byte get next character + + INX ; else increment high byte +LAB_17B3 + JSR LAB_IGBY ; increment and scan memory + JMP LAB_1785 ; loop for next character + +; perform DEC + +LAB_DEC + LDA #LAB_259C ; set +/-1 pointer high byte (both the same) + JSR LAB_246C ; add (AY) to FAC1 + JSR LAB_PFAC ; pack FAC1 into variable (Lvarpl) + + JSR LAB_GBYT ; scan memory + CMP #',' ; compare with "," + BNE LAB_177E ; exit if not "," (either end or error) + + ; was "," so another INCR variable to do + JSR LAB_IGBY ; increment and scan memory + JMP LAB_17B7 ; go do next var + +IncrErr + JMP LAB_1ABC ; do "Type mismatch" error then warm start + +; perform LET + +LAB_LET + JSR LAB_GVAR ; get var address + STA Lvarpl ; save var address low byte + STY Lvarph ; save var address high byte + LDA #TK_EQUAL ; get = token + JSR LAB_SCCA ; scan for CHR$(A), else do syntax error then warm start + LDA Dtypef ; get data type flag, $FF=string, $00=numeric + PHA ; push data type flag + JSR LAB_EVEX ; evaluate expression + PLA ; pop data type flag + ROL ; set carry if type = string + JSR LAB_CKTM ; type match check, set C for string + BNE LAB_17D5 ; branch if string + + JMP LAB_PFAC ; pack FAC1 into variable (Lvarpl) and return + +; string LET + +LAB_17D5 + LDY #$02 ; set index to pointer high byte + LDA (des_pl),Y ; get string pointer high byte + CMP Sstorh ; compare bottom of string space high byte + BCC LAB_17F4 ; if less assign value and exit (was in program memory) + + BNE LAB_17E6 ; branch if > + ; else was equal so compare low bytes + DEY ; decrement index + LDA (des_pl),Y ; get pointer low byte + CMP Sstorl ; compare bottom of string space low byte + BCC LAB_17F4 ; if less assign value and exit (was in program memory) + + ; pointer was >= to bottom of string space pointer +LAB_17E6 + LDY des_ph ; get descriptor pointer high byte + CPY Svarh ; compare start of vars high byte + BCC LAB_17F4 ; branch if less (descriptor is on stack) + + BNE LAB_17FB ; branch if greater (descriptor is not on stack) + + ; else high bytes were equal so .. + LDA des_pl ; get descriptor pointer low byte + CMP Svarl ; compare start of vars low byte + BCS LAB_17FB ; branch if >= (descriptor is not on stack) + +LAB_17F4 + LDA des_pl ; get descriptor pointer low byte + LDY des_ph ; get descriptor pointer high byte + JMP LAB_1811 ; clean stack, copy descriptor to variable and return + + ; make space and copy string +LAB_17FB + LDY #$00 ; index to length + LDA (des_pl),Y ; get string length + JSR LAB_209C ; copy string + LDA des_2l ; get descriptor pointer low byte + LDY des_2h ; get descriptor pointer high byte + STA ssptr_l ; save descriptor pointer low byte + STY ssptr_h ; save descriptor pointer high byte + JSR LAB_228A ; copy string from descriptor (sdescr) to (Sutill) + LDA #FAC1_e ; get descriptor pointer high byte + + ; clean stack and assign value to string variable +LAB_1811 + STA des_2l ; save descriptor_2 pointer low byte + STY des_2h ; save descriptor_2 pointer high byte + JSR LAB_22EB ; clean descriptor stack, YA = pointer + LDY #$00 ; index to length + LDA (des_2l),Y ; get string length + STA (Lvarpl),Y ; copy to let string variable + INY ; index to string pointer low byte + LDA (des_2l),Y ; get string pointer low byte + STA (Lvarpl),Y ; copy to let string variable + INY ; index to string pointer high byte + LDA (des_2l),Y ; get string pointer high byte + STA (Lvarpl),Y ; copy to let string variable + RTS + +; perform GET + +LAB_GET + JSR LAB_GVAR ; get var address + STA Lvarpl ; save var address low byte + STY Lvarph ; save var address high byte + JSR INGET ; get input byte + LDX Dtypef ; get data type flag, $FF=string, $00=numeric + BMI LAB_GETS ; go get string character + + ; was numeric get + TAY ; copy character to Y + JSR LAB_1FD0 ; convert Y to byte in FAC1 + JMP LAB_PFAC ; pack FAC1 into variable (Lvarpl) and return + +LAB_GETS + PHA ; save character + LDA #$01 ; string is single byte + BCS LAB_IsByte ; branch if byte received + + PLA ; string is null +LAB_IsByte + JSR LAB_MSSP ; make string space A bytes long A=$AC=length, + ; X=$AD=Sutill=ptr low byte, Y=$AE=Sutilh=ptr high byte + BEQ LAB_NoSt ; skip store if null string + + PLA ; get character back + LDY #$00 ; clear index + STA (str_pl),Y ; save byte in string (byte IS string!) +LAB_NoSt + JSR LAB_RTST ; check for space on descriptor stack then put address + ; and length on descriptor stack and update stack pointers + + JMP LAB_17D5 ; do string LET and return + +; perform PRINT + +LAB_1829 + JSR LAB_18C6 ; print string from Sutill/Sutilh +LAB_182C + JSR LAB_GBYT ; scan memory + +; PRINT + +LAB_PRINT + BEQ LAB_CRLF ; if nothing following just print CR/LF + +LAB_1831 + CMP #TK_TAB ; compare with TAB( token + BEQ LAB_18A2 ; go do TAB/SPC + + CMP #TK_SPC ; compare with SPC( token + BEQ LAB_18A2 ; go do TAB/SPC + + CMP #',' ; compare with "," + BEQ LAB_188B ; go do move to next TAB mark + + CMP #';' ; compare with ";" + BEQ LAB_18BD ; if ";" continue with PRINT processing + + JSR LAB_EVEX ; evaluate expression + BIT Dtypef ; test data type flag, $FF=string, $00=numeric + BMI LAB_1829 ; branch if string + + JSR LAB_296E ; convert FAC1 to string + JSR LAB_20AE ; print " terminated string to Sutill/Sutilh + LDY #$00 ; clear index + +; don't check fit if terminal width byte is zero + + LDA TWidth ; get terminal width byte + BEQ LAB_185E ; skip check if zero + + SEC ; set carry for subtract + SBC TPos ; subtract terminal position + SBC (des_pl),Y ; subtract string length + BCS LAB_185E ; branch if less than terminal width + + JSR LAB_CRLF ; else print CR/LF +LAB_185E + JSR LAB_18C6 ; print string from Sutill/Sutilh + BEQ LAB_182C ; always go continue processing line + +; CR/LF return to BASIC from BASIC input handler + +LAB_1866 + LDA #$00 ; clear byte + STA Ibuffs,X ; null terminate input + LDX #Ibuffs ; set Y to buffer start-1 high byte + +; print CR/LF + +LAB_CRLF + LDA #$0D ; load [CR] + JSR LAB_PRNA ; go print the character + LDA #$0A ; load [LF] + BNE LAB_PRNA ; go print the character and return, branch always + +LAB_188B + LDA TPos ; get terminal position + CMP Iclim ; compare with input column limit + BCC LAB_1897 ; branch if less + + JSR LAB_CRLF ; else print CR/LF (next line) + BNE LAB_18BD ; continue with PRINT processing (branch always) + +LAB_1897 + SEC ; set carry for subtract +LAB_1898 + SBC TabSiz ; subtract TAB size + BCS LAB_1898 ; loop if result was +ve + + EOR #$FF ; complement it + ADC #$01 ; +1 (twos complement) + BNE LAB_18B6 ; always print A spaces (result is never $00) + + ; do TAB/SPC +LAB_18A2 + PHA ; save token + JSR LAB_SGBY ; scan and get byte parameter + CMP #$29 ; is next character ) + BNE LAB_1910 ; if not do syntax error then warm start + + PLA ; get token back + CMP #TK_TAB ; was it TAB ? + BNE LAB_18B7 ; if not go do SPC + + ; calculate TAB offset + TXA ; copy integer value to A + SBC TPos ; subtract terminal position + BCC LAB_18BD ; branch if result was < 0 (can't TAB backwards) + + ; print A spaces +LAB_18B6 + TAX ; copy result to X +LAB_18B7 + TXA ; set flags on size for SPC + BEQ LAB_18BD ; branch if result was = $0, already here + + ; print X spaces +LAB_18BA + JSR LAB_18E0 ; print " " + DEX ; decrement count + BNE LAB_18BA ; loop if not all done + + ; continue with PRINT processing +LAB_18BD + JSR LAB_IGBY ; increment and scan memory + BNE LAB_1831 ; if more to print go do it + + RTS + +; print null terminated string from memory + +LAB_18C3 + JSR LAB_20AE ; print " terminated string to Sutill/Sutilh + +; print string from Sutill/Sutilh + +LAB_18C6 + JSR LAB_22B6 ; pop string off descriptor stack, or from top of string + ; space returns with A = length, X=$71=pointer low byte, + ; Y=$72=pointer high byte + LDY #$00 ; reset index + TAX ; copy length to X + BEQ LAB_188C ; exit (RTS) if null string + +LAB_18CD + + LDA (ut1_pl),Y ; get next byte + JSR LAB_PRNA ; go print the character + INY ; increment index + DEX ; decrement count + BNE LAB_18CD ; loop if not done yet + + RTS + + ; Print single format character +; print " " + +LAB_18E0 + LDA #$20 ; load " " + .byte $2C ; change next line to BIT LAB_3FA9 + +; print "?" character + +LAB_18E3 + LDA #$3F ; load "?" character + +; print character in A +; now includes the null handler +; also includes infinite line length code +; note! some routines expect this one to exit with Zb=0 + +LAB_PRNA + CMP #' ' ; compare with " " + BCC LAB_18F9 ; branch if less (non printing) + + ; else printable character + PHA ; save the character + +; don't check fit if terminal width byte is zero + + LDA TWidth ; get terminal width + BNE LAB_18F0 ; branch if not zero (not infinite length) + +; is "infinite line" so check TAB position + + LDA TPos ; get position + SBC TabSiz ; subtract TAB size, carry set by CMP #$20 above + BNE LAB_18F7 ; skip reset if different + + STA TPos ; else reset position + BEQ LAB_18F7 ; go print character + +LAB_18F0 + CMP TPos ; compare with terminal character position + BNE LAB_18F7 ; branch if not at end of line + + JSR LAB_CRLF ; else print CR/LF +LAB_18F7 + INC TPos ; increment terminal position + PLA ; get character back +LAB_18F9 + JSR V_OUTP ; output byte via output vector + CMP #$0D ; compare with [CR] + BNE LAB_188A ; branch if not [CR] + + ; else print nullct nulls after the [CR] + STX TempB ; save buffer index + LDX Nullct ; get null count + BEQ LAB_1886 ; branch if no nulls + + LDA #$00 ; load [NULL] +LAB_1880 + JSR LAB_PRNA ; go print the character + DEX ; decrement count + BNE LAB_1880 ; loop if not all done + + LDA #$0D ; restore the character (and set the flags) +LAB_1886 + STX TPos ; clear terminal position (X always = zero when we get here) + LDX TempB ; restore buffer index +LAB_188A + AND #$FF ; set the flags +LAB_188C + RTS + +; handle bad input data + +LAB_1904 + LDA Imode ; get input mode flag, $00=INPUT, $00=READ + BPL LAB_1913 ; branch if INPUT (go do redo) + + LDA Dlinel ; get current DATA line low byte + LDY Dlineh ; get current DATA line high byte + STA Clinel ; save current line low byte + STY Clineh ; save current line high byte +LAB_1910 + JMP LAB_SNER ; do syntax error then warm start + + ; mode was INPUT +LAB_1913 + LDA #LAB_REDO ; point to redo message (high addr) + JSR LAB_18C3 ; print null terminated string from memory + LDA Cpntrl ; get continue pointer low byte + LDY Cpntrh ; get continue pointer high byte + STA Bpntrl ; save BASIC execute pointer low byte + STY Bpntrh ; save BASIC execute pointer high byte + RTS + +; perform INPUT + +LAB_INPUT + CMP #$22 ; compare next byte with open quote + BNE LAB_1934 ; branch if no prompt string + + JSR LAB_1BC1 ; print "..." string + LDA #$3B ; load A with ";" + JSR LAB_SCCA ; scan for CHR$(A), else do syntax error then warm start + JSR LAB_18C6 ; print string from Sutill/Sutilh + + ; done with prompt, now get data +LAB_1934 + JSR LAB_CKRN ; check not Direct, back here if ok + JSR LAB_INLN ; print "? " and get BASIC input + LDA #$00 ; set mode = INPUT + CMP Ibuffs ; test first byte in buffer + BNE LAB_1953 ; branch if not null input + + CLC ; was null input so clear carry to exit program + JMP LAB_1647 ; go do BREAK exit + +; perform READ + +LAB_READ + LDX Dptrl ; get DATA pointer low byte + LDY Dptrh ; get DATA pointer high byte + LDA #$80 ; set mode = READ + +LAB_1953 + STA Imode ; set input mode flag, $00=INPUT, $80=READ + STX Rdptrl ; save READ pointer low byte + STY Rdptrh ; save READ pointer high byte + + ; READ or INPUT next variable from list +LAB_195B + JSR LAB_GVAR ; get (var) address + STA Lvarpl ; save address low byte + STY Lvarph ; save address high byte + LDA Bpntrl ; get BASIC execute pointer low byte + LDY Bpntrh ; get BASIC execute pointer high byte + STA Itempl ; save as temporary integer low byte + STY Itemph ; save as temporary integer high byte + LDX Rdptrl ; get READ pointer low byte + LDY Rdptrh ; get READ pointer high byte + STX Bpntrl ; set BASIC execute pointer low byte + STY Bpntrh ; set BASIC execute pointer high byte + JSR LAB_GBYT ; scan memory + BNE LAB_1988 ; branch if not null + + ; pointer was to null entry + BIT Imode ; test input mode flag, $00=INPUT, $80=READ + BMI LAB_19DD ; branch if READ + + ; mode was INPUT + JSR LAB_18E3 ; print "?" character (double ? for extended input) + JSR LAB_INLN ; print "? " and get BASIC input + STX Bpntrl ; set BASIC execute pointer low byte + STY Bpntrh ; set BASIC execute pointer high byte +LAB_1985 + JSR LAB_GBYT ; scan memory +LAB_1988 + BIT Dtypef ; test data type flag, $FF=string, $00=numeric + BPL LAB_19B0 ; branch if numeric + + ; else get string + STA Srchc ; save search character + CMP #$22 ; was it " ? + BEQ LAB_1999 ; branch if so + + LDA #':' ; else search character is ":" + STA Srchc ; set new search character + LDA #',' ; other search character is "," + CLC ; clear carry for add +LAB_1999 + STA Asrch ; set second search character + LDA Bpntrl ; get BASIC execute pointer low byte + LDY Bpntrh ; get BASIC execute pointer high byte + + ADC #$00 ; c is =1 if we came via the BEQ LAB_1999, else =0 + BCC LAB_19A4 ; branch if no execute pointer low byte rollover + + INY ; else increment high byte +LAB_19A4 + JSR LAB_20B4 ; print Srchc or Asrch terminated string to Sutill/Sutilh + JSR LAB_23F3 ; restore BASIC execute pointer from temp (Btmpl/Btmph) + JSR LAB_17D5 ; go do string LET + JMP LAB_19B6 ; go check string terminator + + ; get numeric INPUT +LAB_19B0 + JSR LAB_2887 ; get FAC1 from string + JSR LAB_PFAC ; pack FAC1 into (Lvarpl) +LAB_19B6 + JSR LAB_GBYT ; scan memory + BEQ LAB_19C5 ; branch if null (last entry) + + CMP #',' ; else compare with "," + BEQ LAB_19C2 ; branch if "," + + JMP LAB_1904 ; else go handle bad input data + + ; got good input data +LAB_19C2 + JSR LAB_IGBY ; increment and scan memory +LAB_19C5 + LDA Bpntrl ; get BASIC execute pointer low byte (temp READ/INPUT ptr) + LDY Bpntrh ; get BASIC execute pointer high byte (temp READ/INPUT ptr) + STA Rdptrl ; save for now + STY Rdptrh ; save for now + LDA Itempl ; get temporary integer low byte (temp BASIC execute ptr) + LDY Itemph ; get temporary integer high byte (temp BASIC execute ptr) + STA Bpntrl ; set BASIC execute pointer low byte + STY Bpntrh ; set BASIC execute pointer high byte + JSR LAB_GBYT ; scan memory + BEQ LAB_1A03 ; if null go do extra ignored message + + JSR LAB_1C01 ; else scan for "," , else do syntax error then warm start + JMP LAB_195B ; go INPUT next variable from list + + ; find next DATA statement or do "Out of DATA" error +LAB_19DD + JSR LAB_SNBS ; scan for next BASIC statement ([:] or [EOL]) + INY ; increment index + TAX ; copy character ([:] or [EOL]) + BNE LAB_19F6 ; branch if [:] + + LDX #$06 ; set for "Out of DATA" error + INY ; increment index, now points to next line pointer high byte + LDA (Bpntrl),Y ; get next line pointer high byte + BEQ LAB_1A54 ; branch if end (eventually does error X) + + INY ; increment index + LDA (Bpntrl),Y ; get next line # low byte + STA Dlinel ; save current DATA line low byte + INY ; increment index + LDA (Bpntrl),Y ; get next line # high byte + INY ; increment index + STA Dlineh ; save current DATA line high byte +LAB_19F6 + LDA (Bpntrl),Y ; get byte + INY ; increment index + TAX ; copy to X + JSR LAB_170F ; set BASIC execute pointer + CPX #TK_DATA ; compare with "DATA" token + BEQ LAB_1985 ; was "DATA" so go do next READ + + BNE LAB_19DD ; go find next statement if not "DATA" + +; end of INPUT/READ routine + +LAB_1A03 + LDA Rdptrl ; get temp READ pointer low byte + LDY Rdptrh ; get temp READ pointer high byte + LDX Imode ; get input mode flag, $00=INPUT, $80=READ + BPL LAB_1A0E ; branch if INPUT + + JMP LAB_1624 ; save AY as DATA pointer and return + + ; we were getting INPUT +LAB_1A0E + LDY #$00 ; clear index + LDA (Rdptrl),Y ; get next byte + BNE LAB_1A1B ; error if not end of INPUT + + RTS + + ; user typed too much +LAB_1A1B + LDA #LAB_IMSG ; point to extra ignored message (high addr) + JMP LAB_18C3 ; print null terminated string from memory and return + +; search the stack for FOR activity +; exit with z=1 if FOR else exit with z=0 + +LAB_11A1 + TSX ; copy stack pointer + INX ; +1 pass return address + INX ; +2 pass return address + INX ; +3 pass calling routine return address + INX ; +4 pass calling routine return address +LAB_11A6 + LDA LAB_STAK+1,X ; get token byte from stack + CMP #TK_FOR ; is it FOR token + BNE LAB_11CE ; exit if not FOR token + + ; was FOR token + LDA Frnxth ; get var pointer for FOR/NEXT high byte + BNE LAB_11BB ; branch if not null + + LDA LAB_STAK+2,X ; get FOR variable pointer low byte + STA Frnxtl ; save var pointer for FOR/NEXT low byte + LDA LAB_STAK+3,X ; get FOR variable pointer high byte + STA Frnxth ; save var pointer for FOR/NEXT high byte +LAB_11BB + CMP LAB_STAK+3,X ; compare var pointer with stacked var pointer (high byte) + BNE LAB_11C7 ; branch if no match + + LDA Frnxtl ; get var pointer for FOR/NEXT low byte + CMP LAB_STAK+2,X ; compare var pointer with stacked var pointer (low byte) + BEQ LAB_11CE ; exit if match found + +LAB_11C7 + TXA ; copy index + CLC ; clear carry for add + ADC #$10 ; add FOR stack use size + TAX ; copy back to index + BNE LAB_11A6 ; loop if not at start of stack + +LAB_11CE + RTS + +; perform NEXT + +LAB_NEXT + BNE LAB_1A46 ; branch if NEXT var + + LDY #$00 ; else clear Y + BEQ LAB_1A49 ; branch always (no variable to search for) + +; NEXT var + +LAB_1A46 + JSR LAB_GVAR ; get variable address +LAB_1A49 + STA Frnxtl ; store variable pointer low byte + STY Frnxth ; store variable pointer high byte + ; (both cleared if no variable defined) + JSR LAB_11A1 ; search the stack for FOR activity + BEQ LAB_1A56 ; branch if found + + LDX #$00 ; else set error $00 ("NEXT without FOR" error) +LAB_1A54 + BEQ LAB_1ABE ; do error #X, then warm start + +LAB_1A56 + TXS ; set stack pointer, X set by search, dumps return addresses + + TXA ; copy stack pointer + SEC ; set carry for subtract + SBC #$F7 ; point to TO var + STA ut2_pl ; save pointer to TO var for compare + ADC #$FB ; point to STEP var + + LDY #>LAB_STAK ; point to stack page high byte + JSR LAB_UFAC ; unpack memory (STEP value) into FAC1 + TSX ; get stack pointer back + LDA LAB_STAK+8,X ; get step sign + STA FAC1_s ; save FAC1 sign (b7) + LDA Frnxtl ; get FOR variable pointer low byte + LDY Frnxth ; get FOR variable pointer high byte + JSR LAB_246C ; add (FOR variable) to FAC1 + JSR LAB_PFAC ; pack FAC1 into (FOR variable) + LDY #>LAB_STAK ; point to stack page high byte + JSR LAB_27FA ; compare FAC1 with (Y,ut2_pl) (TO value) + TSX ; get stack pointer back + CMP LAB_STAK+8,X ; compare step sign + BEQ LAB_1A9B ; branch if = (loop complete) + + ; loop back and do it all again + LDA LAB_STAK+$0D,X ; get FOR line low byte + STA Clinel ; save current line low byte + LDA LAB_STAK+$0E,X ; get FOR line high byte + STA Clineh ; save current line high byte + LDA LAB_STAK+$10,X ; get BASIC execute pointer low byte + STA Bpntrl ; save BASIC execute pointer low byte + LDA LAB_STAK+$0F,X ; get BASIC execute pointer high byte + STA Bpntrh ; save BASIC execute pointer high byte +LAB_1A98 + JMP LAB_15C2 ; go do interpreter inner loop + + ; loop complete so carry on +LAB_1A9B + TXA ; stack copy to A + ADC #$0F ; add $10 ($0F+carry) to dump FOR structure + TAX ; copy back to index + TXS ; copy to stack pointer + JSR LAB_GBYT ; scan memory + CMP #',' ; compare with "," + BNE LAB_1A98 ; branch if not "," (go do interpreter inner loop) + + ; was "," so another NEXT variable to do + JSR LAB_IGBY ; else increment and scan memory + JSR LAB_1A46 ; do NEXT (var) + +; evaluate expression and check is numeric, else do type mismatch + +LAB_EVNM + JSR LAB_EVEX ; evaluate expression + +; check if source is numeric, else do type mismatch + +LAB_CTNM + CLC ; destination is numeric + .byte $24 ; makes next line BIT $38 + +; check if source is string, else do type mismatch + +LAB_CTST + SEC ; required type is string + +; type match check, set C for string, clear C for numeric + +LAB_CKTM + BIT Dtypef ; test data type flag, $FF=string, $00=numeric + BMI LAB_1ABA ; branch if data type is string + + ; else data type was numeric + BCS LAB_1ABC ; if required type is string do type mismatch error +LAB_1AB9 + RTS + + ; data type was string, now check required type +LAB_1ABA + BCS LAB_1AB9 ; exit if required type is string + + ; else do type mismatch error +LAB_1ABC + LDX #$18 ; error code $18 ("Type mismatch" error) +LAB_1ABE + JMP LAB_XERR ; do error #X, then warm start + +; evaluate expression + +LAB_EVEX + LDX Bpntrl ; get BASIC execute pointer low byte + BNE LAB_1AC7 ; skip next if not zero + + DEC Bpntrh ; else decrement BASIC execute pointer high byte +LAB_1AC7 + DEC Bpntrl ; decrement BASIC execute pointer low byte + +LAB_EVEZ + LDA #$00 ; set null precedence (flag done) +LAB_1ACC + PHA ; push precedence byte + LDA #$02 ; 2 bytes + JSR LAB_1212 ; check room on stack for A bytes + JSR LAB_GVAL ; get value from line + LDA #$00 ; clear A + STA comp_f ; clear compare function flag +LAB_1ADB + JSR LAB_GBYT ; scan memory +LAB_1ADE + SEC ; set carry for subtract + SBC #TK_GT ; subtract token for > (lowest comparison function) + BCC LAB_1AFA ; branch if < TK_GT + + CMP #$03 ; compare with ">" to "<" tokens + BCS LAB_1AFA ; branch if >= TK_SGN (highest evaluation function +1) + + ; was token for > = or < (A = 0, 1 or 2) + CMP #$01 ; compare with token for = + ROL ; *2, b0 = carry (=1 if token was = or <) + ; (A = 0, 3 or 5) + EOR #$01 ; toggle b0 + ; (A = 1, 2 or 4. 1 if >, 2 if =, 4 if <) + EOR comp_f ; EOR with compare function flag bits + CMP comp_f ; compare with compare function flag + BCC LAB_1B53 ; if <(comp_f) do syntax error then warm start + ; was more than one <, = or >) + + STA comp_f ; save new compare function flag + JSR LAB_IGBY ; increment and scan memory + JMP LAB_1ADE ; go do next character + + ; token is < ">" or > "<" tokens +LAB_1AFA + LDX comp_f ; get compare function flag + BNE LAB_1B2A ; branch if compare function + + BCS LAB_1B78 ; go do functions + + ; else was < TK_GT so is operator or lower + ADC #TK_GT-TK_PLUS ; add # of operators (+, -, *, /, ^, AND, OR or EOR) + BCC LAB_1B78 ; branch if < + operator + + ; carry was set so token was +, -, *, /, ^, AND, OR or EOR + BNE LAB_1B0B ; branch if not + token + + BIT Dtypef ; test data type flag, $FF=string, $00=numeric + BPL LAB_1B0B ; branch if not string + + ; will only be $00 if type is string and token was + + JMP LAB_224D ; add strings, string 1 is in descriptor des_pl, string 2 + ; is in line, and return + +LAB_1B0B + STA ut1_pl ; save it + ASL ; *2 + ADC ut1_pl ; *3 + TAY ; copy to index +LAB_1B13 + PLA ; pull previous precedence + CMP LAB_OPPT,Y ; compare with precedence byte + BCS LAB_1B7D ; branch if A >= + + JSR LAB_CTNM ; check if source is numeric, else do type mismatch +LAB_1B1C + PHA ; save precedence +LAB_1B1D + JSR LAB_1B43 ; get vector, execute function then continue evaluation + PLA ; restore precedence + LDY prstk ; get precedence stacked flag + BPL LAB_1B3C ; branch if stacked values + + TAX ; copy precedence (set flags) + BEQ LAB_1B9D ; exit if done + + BNE LAB_1B86 ; else pop FAC2 and return, branch always + +LAB_1B2A + ROL Dtypef ; shift data type flag into Cb + TXA ; copy compare function flag + STA Dtypef ; clear data type flag, X is 0xxx xxxx + ROL ; shift data type into compare function byte b0 + LDX Bpntrl ; get BASIC execute pointer low byte + BNE LAB_1B34 ; branch if no underflow + + DEC Bpntrh ; else decrement BASIC execute pointer high byte +LAB_1B34 + DEC Bpntrl ; decrement BASIC execute pointer low byte +TK_LT_PLUS = TK_LT-TK_PLUS + LDY #TK_LT_PLUS*3 ; set offset to last operator entry + STA comp_f ; save new compare function flag + BNE LAB_1B13 ; branch always + +LAB_1B3C + CMP LAB_OPPT,Y ;.compare with stacked function precedence + BCS LAB_1B86 ; branch if A >=, pop FAC2 and return + + BCC LAB_1B1C ; branch always + +;.get vector, execute function then continue evaluation + +LAB_1B43 + LDA LAB_OPPT+2,Y ; get function vector high byte + PHA ; onto stack + LDA LAB_OPPT+1,Y ; get function vector low byte + PHA ; onto stack + ; now push sign, round FAC1 and put on stack + JSR LAB_1B5B ; function will return here, then the next RTS will call + ; the function + LDA comp_f ; get compare function flag + PHA ; push compare evaluation byte + LDA LAB_OPPT,Y ; get precedence byte + JMP LAB_1ACC ; continue evaluating expression + +LAB_1B53 + JMP LAB_SNER ; do syntax error then warm start + +; push sign, round FAC1 and put on stack + +LAB_1B5B + PLA ; get return addr low byte + STA ut1_pl ; save it + INC ut1_pl ; increment it (was ret-1 pushed? yes!) + ; note! no check is made on the high byte! if the calling + ; routine assembles to a page edge then this all goes + ; horribly wrong !!! + PLA ; get return addr high byte + STA ut1_ph ; save it + LDA FAC1_s ; get FAC1 sign (b7) + PHA ; push sign + +; round FAC1 and put on stack + +LAB_1B66 + JSR LAB_27BA ; round FAC1 + LDA FAC1_3 ; get FAC1 mantissa3 + PHA ; push on stack + LDA FAC1_2 ; get FAC1 mantissa2 + PHA ; push on stack + LDA FAC1_1 ; get FAC1 mantissa1 + PHA ; push on stack + LDA FAC1_e ; get FAC1 exponent + PHA ; push on stack + JMP (ut1_pl) ; return, sort of + +; do functions + +LAB_1B78 + LDY #$FF ; flag function + PLA ; pull precedence byte +LAB_1B7B + BEQ LAB_1B9D ; exit if done + +LAB_1B7D + CMP #$64 ; compare previous precedence with $64 + BEQ LAB_1B84 ; branch if was $64 (< function) + + JSR LAB_CTNM ; check if source is numeric, else do type mismatch +LAB_1B84 + STY prstk ; save precedence stacked flag + + ; pop FAC2 and return +LAB_1B86 + PLA ; pop byte + LSR ; shift out comparison evaluation lowest bit + STA Cflag ; save comparison evaluation flag + PLA ; pop exponent + STA FAC2_e ; save FAC2 exponent + PLA ; pop mantissa1 + STA FAC2_1 ; save FAC2 mantissa1 + PLA ; pop mantissa2 + STA FAC2_2 ; save FAC2 mantissa2 + PLA ; pop mantissa3 + STA FAC2_3 ; save FAC2 mantissa3 + PLA ; pop sign + STA FAC2_s ; save FAC2 sign (b7) + EOR FAC1_s ; EOR FAC1 sign (b7) + STA FAC_sc ; save sign compare (FAC1 EOR FAC2) +LAB_1B9D + LDA FAC1_e ; get FAC1 exponent + RTS + +; print "..." string to string util area + +LAB_1BC1 + LDA Bpntrl ; get BASIC execute pointer low byte + LDY Bpntrh ; get BASIC execute pointer high byte + ADC #$00 ; add carry to low byte + BCC LAB_1BCA ; branch if no overflow + + INY ; increment high byte +LAB_1BCA + JSR LAB_20AE ; print " terminated string to Sutill/Sutilh + JMP LAB_23F3 ; restore BASIC execute pointer from temp and return + +; get value from line + +LAB_GVAL + JSR LAB_IGBY ; increment and scan memory + BCS LAB_1BAC ; branch if not numeric character + + ; else numeric string found (e.g. 123) +LAB_1BA9 + JMP LAB_2887 ; get FAC1 from string and return + +; get value from line .. continued + + ; wasn't a number so .. +LAB_1BAC + TAX ; set the flags + BMI LAB_1BD0 ; if -ve go test token values + + ; else it is either a string, number, variable or () + CMP #'$' ; compare with "$" + BEQ LAB_1BA9 ; branch if "$", hex number + + CMP #'%' ; else compare with "%" + BEQ LAB_1BA9 ; branch if "%", binary number + + CMP #'.' ; compare with "." + BEQ LAB_1BA9 ; if so get FAC1 from string and return (e.g. was .123) + + ; it wasn't any sort of number so .. + CMP #$22 ; compare with " + BEQ LAB_1BC1 ; branch if open quote + + ; wasn't any sort of number so .. + +; evaluate expression within parentheses + + CMP #'(' ; compare with "(" + BNE LAB_1C18 ; if not "(" get (var), return value in FAC1 and $ flag + +LAB_1BF7 + JSR LAB_EVEZ ; evaluate expression, no decrement + +; all the 'scan for' routines return the character after the sought character + +; scan for ")" , else do syntax error then warm start + +LAB_1BFB + LDA #$29 ; load A with ")" + +; scan for CHR$(A) , else do syntax error then warm start + +LAB_SCCA + LDY #$00 ; clear index + CMP (Bpntrl),Y ; check next byte is = A + BNE LAB_SNER ; if not do syntax error then warm start + + JMP LAB_IGBY ; increment and scan memory then return + +; scan for "(" , else do syntax error then warm start + +LAB_1BFE + LDA #$28 ; load A with "(" + BNE LAB_SCCA ; scan for CHR$(A), else do syntax error then warm start + ; (branch always) + +; scan for "," , else do syntax error then warm start + +LAB_1C01 + LDA #$2C ; load A with "," + BNE LAB_SCCA ; scan for CHR$(A), else do syntax error then warm start + ; (branch always) + +; syntax error then warm start + +LAB_SNER + LDX #$02 ; error code $02 ("Syntax" error) + JMP LAB_XERR ; do error #X, then warm start + +; get value from line .. continued +; do tokens + +LAB_1BD0 + CMP #TK_MINUS ; compare with token for - + BEQ LAB_1C11 ; branch if - token (do set-up for functions) + + ; wasn't -n so .. + CMP #TK_PLUS ; compare with token for + + BEQ LAB_GVAL ; branch if + token (+n = n so ignore leading +) + + CMP #TK_NOT ; compare with token for NOT + BNE LAB_1BE7 ; branch if not token for NOT + + ; was NOT token +TK_EQUAL_PLUS = TK_EQUAL-TK_PLUS + LDY #TK_EQUAL_PLUS*3 ; offset to NOT function + BNE LAB_1C13 ; do set-up for function then execute (branch always) + +; do = compare + +LAB_EQUAL + JSR LAB_EVIR ; evaluate integer expression (no sign check) + LDA FAC1_3 ; get FAC1 mantissa3 + EOR #$FF ; invert it + TAY ; copy it + LDA FAC1_2 ; get FAC1 mantissa2 + EOR #$FF ; invert it + JMP LAB_AYFC ; save and convert integer AY to FAC1 and return + +; get value from line .. continued + + ; wasn't +, -, or NOT so .. +LAB_1BE7 + CMP #TK_FN ; compare with token for FN + BNE LAB_1BEE ; branch if not token for FN + + JMP LAB_201E ; go evaluate FNx + +; get value from line .. continued + + ; wasn't +, -, NOT or FN so .. +LAB_1BEE + SBC #TK_SGN ; subtract with token for SGN + BCS LAB_1C27 ; if a function token go do it + + JMP LAB_SNER ; else do syntax error + +; set-up for functions + +LAB_1C11 +TK_GT_PLUS = TK_GT-TK_PLUS + LDY #TK_GT_PLUS*3 ; set offset from base to > operator +LAB_1C13 + PLA ; dump return address low byte + PLA ; dump return address high byte + JMP LAB_1B1D ; execute function then continue evaluation + +; variable name set-up +; get (var), return value in FAC_1 and $ flag + +LAB_1C18 + JSR LAB_GVAR ; get (var) address + STA FAC1_2 ; save address low byte in FAC1 mantissa2 + STY FAC1_3 ; save address high byte in FAC1 mantissa3 + LDX Dtypef ; get data type flag, $FF=string, $00=numeric + BMI LAB_1C25 ; if string then return (does RTS) + +LAB_1C24 + JMP LAB_UFAC ; unpack memory (AY) into FAC1 + +LAB_1C25 + RTS + +; get value from line .. continued +; only functions left so .. + +; set up function references + +; new for V2.0+ this replaces a lot of IF .. THEN .. ELSEIF .. THEN .. that was needed +; to process function calls. now the function vector is computed and pushed on the stack +; and the preprocess offset is read. if the preprocess offset is non zero then the vector +; is calculated and the routine called, if not this routine just does RTS. whichever +; happens the RTS at the end of this routine, or the end of the preprocess routine, calls +; the function code + +; this also removes some less than elegant code that was used to bypass type checking +; for functions that returned strings + +LAB_1C27 + ASL ; *2 (2 bytes per function address) + TAY ; copy to index + + LDA LAB_FTBM,Y ; get function jump vector high byte + PHA ; push functions jump vector high byte + LDA LAB_FTBL,Y ; get function jump vector low byte + PHA ; push functions jump vector low byte + + LDA LAB_FTPM,Y ; get function pre process vector high byte + BEQ LAB_1C56 ; skip pre process if null vector + + PHA ; push functions pre process vector high byte + LDA LAB_FTPL,Y ; get function pre process vector low byte + PHA ; push functions pre process vector low byte + +LAB_1C56 + RTS ; do function, or pre process, call + +; process string expression in parenthesis + +LAB_PPFS + JSR LAB_1BF7 ; process expression in parenthesis + JMP LAB_CTST ; check if source is string then do function, + ; else do type mismatch + +; process numeric expression in parenthesis + +LAB_PPFN + JSR LAB_1BF7 ; process expression in parenthesis + JMP LAB_CTNM ; check if source is numeric then do function, + ; else do type mismatch + +; set numeric data type and increment BASIC execute pointer + +LAB_PPBI + LSR Dtypef ; clear data type flag, $FF=string, $00=numeric + JMP LAB_IGBY ; increment and scan memory then do function + +; process string for LEFT$, RIGHT$ or MID$ + +LAB_LRMS + JSR LAB_EVEZ ; evaluate (should be string) expression + JSR LAB_1C01 ; scan for ",", else do syntax error then warm start + JSR LAB_CTST ; check if source is string, else do type mismatch + + PLA ; get function jump vector low byte + TAX ; save functions jump vector low byte + PLA ; get function jump vector high byte + TAY ; save functions jump vector high byte + LDA des_ph ; get descriptor pointer high byte + PHA ; push string pointer high byte + LDA des_pl ; get descriptor pointer low byte + PHA ; push string pointer low byte + TYA ; get function jump vector high byte back + PHA ; save functions jump vector high byte + TXA ; get function jump vector low byte back + PHA ; save functions jump vector low byte + JSR LAB_GTBY ; get byte parameter + TXA ; copy byte parameter to A + RTS ; go do function + +; process numeric expression(s) for BIN$ or HEX$ + +LAB_BHSS + JSR LAB_EVEZ ; process expression + JSR LAB_CTNM ; check if source is numeric, else do type mismatch + LDA FAC1_e ; get FAC1 exponent + CMP #$98 ; compare with exponent = 2^24 + BCS LAB_BHER ; branch if n>=2^24 (is too big) + + JSR LAB_2831 ; convert FAC1 floating-to-fixed + LDX #$02 ; 3 bytes to do +LAB_CFAC + LDA FAC1_1,X ; get byte from FAC1 + STA nums_1,X ; save byte to temp + DEX ; decrement index + BPL LAB_CFAC ; copy FAC1 mantissa to temp + + JSR LAB_GBYT ; get next BASIC byte + LDX #$00 ; set default to no leading "0"s + CMP #')' ; compare with close bracket + BEQ LAB_1C54 ; if ")" go do rest of function + + JSR LAB_SCGB ; scan for "," and get byte + JSR LAB_GBYT ; get last byte back + CMP #')' ; is next character ) + BNE LAB_BHER ; if not ")" go do error + +LAB_1C54 + RTS ; else do function + +LAB_BHER + JMP LAB_FCER ; do function call error then warm start + +; perform EOR + +; added operator format is the same as AND or OR, precedence is the same as OR + +; this bit worked first time but it took a while to sort out the operator table +; pointers and offsets afterwards! + +LAB_EOR + JSR GetFirst ; get first integer expression (no sign check) + EOR XOAw_l ; EOR with expression 1 low byte + TAY ; save in Y + LDA FAC1_2 ; get FAC1 mantissa2 + EOR XOAw_h ; EOR with expression 1 high byte + JMP LAB_AYFC ; save and convert integer AY to FAC1 and return + +; perform OR + +LAB_OR + JSR GetFirst ; get first integer expression (no sign check) + ORA XOAw_l ; OR with expression 1 low byte + TAY ; save in Y + LDA FAC1_2 ; get FAC1 mantissa2 + ORA XOAw_h ; OR with expression 1 high byte + JMP LAB_AYFC ; save and convert integer AY to FAC1 and return + +; perform AND + +LAB_AND + JSR GetFirst ; get first integer expression (no sign check) + AND XOAw_l ; AND with expression 1 low byte + TAY ; save in Y + LDA FAC1_2 ; get FAC1 mantissa2 + AND XOAw_h ; AND with expression 1 high byte + JMP LAB_AYFC ; save and convert integer AY to FAC1 and return + +; get first value for OR, AND or EOR + +GetFirst + JSR LAB_EVIR ; evaluate integer expression (no sign check) + LDA FAC1_2 ; get FAC1 mantissa2 + STA XOAw_h ; save it + LDA FAC1_3 ; get FAC1 mantissa3 + STA XOAw_l ; save it + JSR LAB_279B ; copy FAC2 to FAC1 (get 2nd value in expression) + JSR LAB_EVIR ; evaluate integer expression (no sign check) + LDA FAC1_3 ; get FAC1 mantissa3 +LAB_1C95 + RTS + +; perform comparisons + +; do < compare + +LAB_LTHAN + JSR LAB_CKTM ; type match check, set C for string + BCS LAB_1CAE ; branch if string + + ; do numeric < compare + LDA FAC2_s ; get FAC2 sign (b7) + ORA #$7F ; set all non sign bits + AND FAC2_1 ; and FAC2 mantissa1 (AND in sign bit) + STA FAC2_1 ; save FAC2 mantissa1 + LDA #FAC2_e ; set pointer high byte to FAC2 + JSR LAB_27F8 ; compare FAC1 with FAC2 (AY) + TAX ; copy result + JMP LAB_1CE1 ; go evaluate result + + ; do string < compare +LAB_1CAE + LSR Dtypef ; clear data type flag, $FF=string, $00=numeric + DEC comp_f ; clear < bit in compare function flag + JSR LAB_22B6 ; pop string off descriptor stack, or from top of string + ; space returns with A = length, X=pointer low byte, + ; Y=pointer high byte + STA str_ln ; save length + STX str_pl ; save string pointer low byte + STY str_ph ; save string pointer high byte + LDA FAC2_2 ; get descriptor pointer low byte + LDY FAC2_3 ; get descriptor pointer high byte + JSR LAB_22BA ; pop (YA) descriptor off stack or from top of string space + ; returns with A = length, X=pointer low byte, + ; Y=pointer high byte + STX FAC2_2 ; save string pointer low byte + STY FAC2_3 ; save string pointer high byte + TAX ; copy length + SEC ; set carry for subtract + SBC str_ln ; subtract string 1 length + BEQ LAB_1CD6 ; branch if str 1 length = string 2 length + + LDA #$01 ; set str 1 length > string 2 length + BCC LAB_1CD6 ; branch if so + + LDX str_ln ; get string 1 length + LDA #$FF ; set str 1 length < string 2 length +LAB_1CD6 + STA FAC1_s ; save length compare + LDY #$FF ; set index + INX ; adjust for loop +LAB_1CDB + INY ; increment index + DEX ; decrement count + BNE LAB_1CE6 ; branch if still bytes to do + + LDX FAC1_s ; get length compare back +LAB_1CE1 + BMI LAB_1CF2 ; branch if str 1 < str 2 + + CLC ; flag str 1 <= str 2 + BCC LAB_1CF2 ; go evaluate result + +LAB_1CE6 + LDA (FAC2_2),Y ; get string 2 byte + CMP (FAC1_1),Y ; compare with string 1 byte + BEQ LAB_1CDB ; loop if bytes = + + LDX #$FF ; set str 1 < string 2 + BCS LAB_1CF2 ; branch if so + + LDX #$01 ; set str 1 > string 2 +LAB_1CF2 + INX ; x = 0, 1 or 2 + TXA ; copy to A + ROL ; *2 (1, 2 or 4) + AND Cflag ; AND with comparison evaluation flag + BEQ LAB_1CFB ; branch if 0 (compare is false) + + LDA #$FF ; else set result true +LAB_1CFB + JMP LAB_27DB ; save A as integer byte and return + +LAB_1CFE + JSR LAB_1C01 ; scan for ",", else do syntax error then warm start + +; perform DIM + +LAB_DIM + TAX ; copy "DIM" flag to X + JSR LAB_1D10 ; search for variable + JSR LAB_GBYT ; scan memory + BNE LAB_1CFE ; scan for "," and loop if not null + + RTS + +; perform << (left shift) + +LAB_LSHIFT + JSR GetPair ; get integer expression and byte (no sign check) + LDA FAC1_2 ; get expression high byte + LDX TempB ; get shift count + BEQ NoShift ; branch if zero + + CPX #$10 ; compare bit count with 16d + BCS TooBig ; branch if >= + +Ls_loop + ASL FAC1_3 ; shift low byte + ROL ; shift high byte + DEX ; decrement bit count + BNE Ls_loop ; loop if shift not complete + + LDY FAC1_3 ; get expression low byte + JMP LAB_AYFC ; save and convert integer AY to FAC1 and return + +; perform >> (right shift) + +LAB_RSHIFT + JSR GetPair ; get integer expression and byte (no sign check) + LDA FAC1_2 ; get expression high byte + LDX TempB ; get shift count + BEQ NoShift ; branch if zero + + CPX #$10 ; compare bit count with 16d + BCS TooBig ; branch if >= + +Rs_loop + LSR ; shift high byte + ROR FAC1_3 ; shift low byte + DEX ; decrement bit count + BNE Rs_loop ; loop if shift not complete + +NoShift + LDY FAC1_3 ; get expression low byte + JMP LAB_AYFC ; save and convert integer AY to FAC1 and return + +TooBig + LDA #$00 ; clear high byte + TAY ; copy to low byte + JMP LAB_AYFC ; save and convert integer AY to FAC1 and return + +GetPair + JSR LAB_EVBY ; evaluate byte expression, result in X + STX TempB ; save it + JSR LAB_279B ; copy FAC2 to FAC1 (get 2nd value in expression) + JMP LAB_EVIR ; evaluate integer expression (no sign check) + +; search for variable + +; return pointer to variable in Cvaral/Cvarah + +LAB_GVAR + LDX #$00 ; set DIM flag = $00 + JSR LAB_GBYT ; scan memory (1st character) +LAB_1D10 + STX Defdim ; save DIM flag +LAB_1D12 + STA Varnm1 ; save 1st character + AND #$7F ; clear FN flag bit + JSR LAB_CASC ; check byte, return C=0 if<"A" or >"Z" + BCS LAB_1D1F ; branch if ok + + JMP LAB_SNER ; else syntax error then warm start + + ; was variable name so .. +LAB_1D1F + LDX #$00 ; clear 2nd character temp + STX Dtypef ; clear data type flag, $FF=string, $00=numeric + JSR LAB_IGBY ; increment and scan memory (2nd character) + BCC LAB_1D2D ; branch if character = "0"-"9" (ok) + + ; 2nd character wasn't "0" to "9" so .. + JSR LAB_CASC ; check byte, return C=0 if<"A" or >"Z" + BCC LAB_1D38 ; branch if <"A" or >"Z" (go check if string) + +LAB_1D2D + TAX ; copy 2nd character + + ; ignore further (valid) characters in the variable name +LAB_1D2E + JSR LAB_IGBY ; increment and scan memory (3rd character) + BCC LAB_1D2E ; loop if character = "0"-"9" (ignore) + + JSR LAB_CASC ; check byte, return C=0 if<"A" or >"Z" + BCS LAB_1D2E ; loop if character = "A"-"Z" (ignore) + + ; check if string variable +LAB_1D38 + CMP #'$' ; compare with "$" + BNE LAB_1D47 ; branch if not string + +; to introduce a new variable type (% suffix for integers say) then this branch +; will need to go to that check and then that branch, if it fails, go to LAB_1D47 + + ; type is string + LDA #$FF ; set data type = string + STA Dtypef ; set data type flag, $FF=string, $00=numeric + TXA ; get 2nd character back + ORA #$80 ; set top bit (indicate string var) + TAX ; copy back to 2nd character temp + JSR LAB_IGBY ; increment and scan memory + +; after we have determined the variable type we need to come back here to determine +; if it's an array of type. this would plug in a%(b[,c[,d]])) integer arrays nicely + + +LAB_1D47 ; gets here with character after var name in A + STX Varnm2 ; save 2nd character + ORA Sufnxf ; or with subscript/FNX flag (or FN name) + CMP #'(' ; compare with "(" + BNE LAB_1D53 ; branch if not "(" + + JMP LAB_1E17 ; go find, or make, array + +; either find or create var +; var name (1st two characters only!) is in Varnm1,Varnm2 + + ; variable name wasn't var(... so look for plain var +LAB_1D53 + LDA #$00 ; clear A + STA Sufnxf ; clear subscript/FNX flag + LDA Svarl ; get start of vars low byte + LDX Svarh ; get start of vars high byte + LDY #$00 ; clear index +LAB_1D5D + STX Vrschh ; save search address high byte +LAB_1D5F + STA Vrschl ; save search address low byte + CPX Sarryh ; compare high address with var space end + BNE LAB_1D69 ; skip next compare if <> + + ; high addresses were = so compare low addresses + CMP Sarryl ; compare low address with var space end + BEQ LAB_1D8B ; if not found go make new var + +LAB_1D69 + LDA Varnm1 ; get 1st character of var to find + CMP (Vrschl),Y ; compare with variable name 1st character + BNE LAB_1D77 ; branch if no match + + ; 1st characters match so compare 2nd characters + LDA Varnm2 ; get 2nd character of var to find + INY ; index to point to variable name 2nd character + CMP (Vrschl),Y ; compare with variable name 2nd character + BEQ LAB_1DD7 ; branch if match (found var) + + DEY ; else decrement index (now = $00) +LAB_1D77 + CLC ; clear carry for add + LDA Vrschl ; get search address low byte + ADC #$06 ; +6 (offset to next var name) + BCC LAB_1D5F ; loop if no overflow to high byte + + INX ; else increment high byte + BNE LAB_1D5D ; loop always (RAM doesn't extend to $FFFF !) + +; check byte, return C=0 if<"A" or >"Z" or "a" to "z" + +LAB_CASC + CMP #'a' ; compare with "a" + BCS LAB_1D83 ; go check <"z"+1 + +; check byte, return C=0 if<"A" or >"Z" + +LAB_1D82 + CMP #'A' ; compare with "A" + BCC LAB_1D8A ; exit if less + + ; carry is set + SBC #$5B ; subtract "Z"+1 + SEC ; set carry + SBC #$A5 ; subtract $A5 (restore byte) + ; carry clear if byte>$5A +LAB_1D8A + RTS + +LAB_1D83 + SBC #$7B ; subtract "z"+1 + SEC ; set carry + SBC #$85 ; subtract $85 (restore byte) + ; carry clear if byte>$7A + RTS + + ; reached end of variable mem without match + ; .. so create new variable +LAB_1D8B + PLA ; pop return address low byte + PHA ; push return address low byte +LAB_1C18p2 = LAB_1C18+2 + CMP #LAB_1D96 ; high byte point to $00,$00 + RTS + + ; create new numeric variable +LAB_1D98 + LDA Sarryl ; get var mem end low byte + LDY Sarryh ; get var mem end high byte + STA Ostrtl ; save old block start low byte + STY Ostrth ; save old block start high byte + LDA Earryl ; get array mem end low byte + LDY Earryh ; get array mem end high byte + STA Obendl ; save old block end low byte + STY Obendh ; save old block end high byte + CLC ; clear carry for add + ADC #$06 ; +6 (space for one var) + BCC LAB_1DAE ; branch if no overflow to high byte + + INY ; else increment high byte +LAB_1DAE + STA Nbendl ; set new block end low byte + STY Nbendh ; set new block end high byte + JSR LAB_11CF ; open up space in memory + LDA Nbendl ; get new start low byte + LDY Nbendh ; get new start high byte (-$100) + INY ; correct high byte + STA Sarryl ; save new var mem end low byte + STY Sarryh ; save new var mem end high byte + LDY #$00 ; clear index + LDA Varnm1 ; get var name 1st character + STA (Vrschl),Y ; save var name 1st character + INY ; increment index + LDA Varnm2 ; get var name 2nd character + STA (Vrschl),Y ; save var name 2nd character + LDA #$00 ; clear A + INY ; increment index + STA (Vrschl),Y ; initialise var byte + INY ; increment index + STA (Vrschl),Y ; initialise var byte + INY ; increment index + STA (Vrschl),Y ; initialise var byte + INY ; increment index + STA (Vrschl),Y ; initialise var byte + + ; found a match for var ((Vrschl) = ptr) +LAB_1DD7 + LDA Vrschl ; get var address low byte + CLC ; clear carry for add + ADC #$02 ; +2 (offset past var name bytes) + LDY Vrschh ; get var address high byte + BCC LAB_1DE1 ; branch if no overflow from add + + INY ; else increment high byte +LAB_1DE1 + STA Cvaral ; save current var address low byte + STY Cvarah ; save current var address high byte + RTS + +; set-up array pointer (Adatal/h) to first element in array +; set Adatal,Adatah to Astrtl,Astrth+2*Dimcnt+#$05 + +LAB_1DE6 + LDA Dimcnt ; get # of dimensions (1, 2 or 3) + ASL ; *2 (also clears the carry !) + ADC #$05 ; +5 (result is 7, 9 or 11 here) + ADC Astrtl ; add array start pointer low byte + LDY Astrth ; get array pointer high byte + BCC LAB_1DF2 ; branch if no overflow + + INY ; else increment high byte +LAB_1DF2 + STA Adatal ; save array data pointer low byte + STY Adatah ; save array data pointer high byte + RTS + +; evaluate integer expression + +LAB_EVIN + JSR LAB_IGBY ; increment and scan memory + JSR LAB_EVNM ; evaluate expression and check is numeric, + ; else do type mismatch + +; evaluate integer expression (no check) + +LAB_EVPI + LDA FAC1_s ; get FAC1 sign (b7) + BMI LAB_1E12 ; do function call error if -ve + +; evaluate integer expression (no sign check) + +LAB_EVIR + LDA FAC1_e ; get FAC1 exponent + CMP #$90 ; compare with exponent = 2^16 (n>2^15) + BCC LAB_1E14 ; branch if n<2^16 (is ok) + + LDA #LAB_1DF7 ; set pointer high byte to -32768 + JSR LAB_27F8 ; compare FAC1 with (AY) +LAB_1E12 + BNE LAB_FCER ; if <> do function call error then warm start + +LAB_1E14 + JMP LAB_2831 ; convert FAC1 floating-to-fixed and return + +; find or make array + +LAB_1E17 + LDA Defdim ; get DIM flag + PHA ; push it + LDA Dtypef ; get data type flag, $FF=string, $00=numeric + PHA ; push it + LDY #$00 ; clear dimensions count + +; now get the array dimension(s) and stack it (them) before the data type and DIM flag + +LAB_1E1F + TYA ; copy dimensions count + PHA ; save it + LDA Varnm2 ; get array name 2nd byte + PHA ; save it + LDA Varnm1 ; get array name 1st byte + PHA ; save it + JSR LAB_EVIN ; evaluate integer expression + PLA ; pull array name 1st byte + STA Varnm1 ; restore array name 1st byte + PLA ; pull array name 2nd byte + STA Varnm2 ; restore array name 2nd byte + PLA ; pull dimensions count + TAY ; restore it + TSX ; copy stack pointer + LDA LAB_STAK+2,X ; get DIM flag + PHA ; push it + LDA LAB_STAK+1,X ; get data type flag + PHA ; push it + LDA FAC1_2 ; get this dimension size high byte + STA LAB_STAK+2,X ; stack before flag bytes + LDA FAC1_3 ; get this dimension size low byte + STA LAB_STAK+1,X ; stack before flag bytes + INY ; increment dimensions count + JSR LAB_GBYT ; scan memory + CMP #',' ; compare with "," + BEQ LAB_1E1F ; if found go do next dimension + + STY Dimcnt ; store dimensions count + JSR LAB_1BFB ; scan for ")" , else do syntax error then warm start + PLA ; pull data type flag + STA Dtypef ; restore data type flag, $FF=string, $00=numeric + PLA ; pull DIM flag + STA Defdim ; restore DIM flag + LDX Sarryl ; get array mem start low byte + LDA Sarryh ; get array mem start high byte + +; now check to see if we are at the end of array memory (we would be if there were +; no arrays). + +LAB_1E5C + STX Astrtl ; save as array start pointer low byte + STA Astrth ; save as array start pointer high byte + CMP Earryh ; compare with array mem end high byte + BNE LAB_1E68 ; branch if not reached array mem end + + CPX Earryl ; else compare with array mem end low byte + BEQ LAB_1EA1 ; go build array if not found + + ; search for array +LAB_1E68 + LDY #$00 ; clear index + LDA (Astrtl),Y ; get array name first byte + INY ; increment index to second name byte + CMP Varnm1 ; compare with this array name first byte + BNE LAB_1E77 ; branch if no match + + LDA Varnm2 ; else get this array name second byte + CMP (Astrtl),Y ; compare with array name second byte + BEQ LAB_1E8D ; array found so branch + + ; no match +LAB_1E77 + INY ; increment index + LDA (Astrtl),Y ; get array size low byte + CLC ; clear carry for add + ADC Astrtl ; add array start pointer low byte + TAX ; copy low byte to X + INY ; increment index + LDA (Astrtl),Y ; get array size high byte + ADC Astrth ; add array mem pointer high byte + BCC LAB_1E5C ; if no overflow go check next array + +; do array bounds error + +LAB_1E85 + LDX #$10 ; error code $10 ("Array bounds" error) + .byte $2C ; makes next bit BIT LAB_08A2 + +; do function call error + +LAB_FCER + LDX #$08 ; error code $08 ("Function call" error) +LAB_1E8A + JMP LAB_XERR ; do error #X, then warm start + + ; found array, are we trying to dimension it? +LAB_1E8D + LDX #$12 ; set error $12 ("Double dimension" error) + LDA Defdim ; get DIM flag + BNE LAB_1E8A ; if we are trying to dimension it do error #X, then warm + ; start + +; found the array and we're not dimensioning it so we must find an element in it + + JSR LAB_1DE6 ; set-up array pointer (Adatal/h) to first element in array + ; (Astrtl,Astrth points to start of array) + LDA Dimcnt ; get dimensions count + LDY #$04 ; set index to array's # of dimensions + CMP (Astrtl),Y ; compare with no of dimensions + BNE LAB_1E85 ; if wrong do array bounds error, could do "Wrong + ; dimensions" error here .. if we want a different + ; error message + + JMP LAB_1F28 ; found array so go get element + ; (could jump to LAB_1F28 as all LAB_1F24 does is take + ; Dimcnt and save it at (Astrtl),Y which is already the + ; same or we would have taken the BNE) + + ; array not found, so build it +LAB_1EA1 + JSR LAB_1DE6 ; set-up array pointer (Adatal/h) to first element in array + ; (Astrtl,Astrth points to start of array) + JSR LAB_121F ; check available memory, "Out of memory" error if no room + ; addr to check is in AY (low/high) + LDY #$00 ; clear Y (don't need to clear A) + STY Aspth ; clear array data size high byte + LDA Varnm1 ; get variable name 1st byte + STA (Astrtl),Y ; save array name 1st byte + INY ; increment index + LDA Varnm2 ; get variable name 2nd byte + STA (Astrtl),Y ; save array name 2nd byte + LDA Dimcnt ; get dimensions count + LDY #$04 ; index to dimension count + STY Asptl ; set array data size low byte (four bytes per element) + STA (Astrtl),Y ; set array's dimensions count + + ; now calculate the size of the data space for the array + CLC ; clear carry for add (clear on subsequent loops) +LAB_1EC0 + LDX #$0B ; set default dimension value low byte + LDA #$00 ; set default dimension value high byte + BIT Defdim ; test default DIM flag + BVC LAB_1ED0 ; branch if b6 of Defdim is clear + + PLA ; else pull dimension value low byte + ADC #$01 ; +1 (allow for zeroeth element) + TAX ; copy low byte to X + PLA ; pull dimension value high byte + ADC #$00 ; add carry from low byte + +LAB_1ED0 + INY ; index to dimension value high byte + STA (Astrtl),Y ; save dimension value high byte + INY ; index to dimension value high byte + TXA ; get dimension value low byte + STA (Astrtl),Y ; save dimension value low byte + JSR LAB_1F7C ; does XY = (Astrtl),Y * (Asptl) + STX Asptl ; save array data size low byte + STA Aspth ; save array data size high byte + LDY ut1_pl ; restore index (saved by subroutine) + DEC Dimcnt ; decrement dimensions count + BNE LAB_1EC0 ; loop while not = 0 + + ADC Adatah ; add size high byte to first element high byte + ; (carry is always clear here) + BCS LAB_1F45 ; if overflow go do "Out of memory" error + + STA Adatah ; save end of array high byte + TAY ; copy end high byte to Y + TXA ; get array size low byte + ADC Adatal ; add array start low byte + BCC LAB_1EF3 ; branch if no carry + + INY ; else increment end of array high byte + BEQ LAB_1F45 ; if overflow go do "Out of memory" error + + ; set-up mostly complete, now zero the array +LAB_1EF3 + JSR LAB_121F ; check available memory, "Out of memory" error if no room + ; addr to check is in AY (low/high) + STA Earryl ; save array mem end low byte + STY Earryh ; save array mem end high byte + LDA #$00 ; clear byte for array clear + INC Aspth ; increment array size high byte (now block count) + LDY Asptl ; get array size low byte (now index to block) + BEQ LAB_1F07 ; branch if low byte = $00 + +LAB_1F02 + DEY ; decrement index (do 0 to n-1) + STA (Adatal),Y ; zero byte + BNE LAB_1F02 ; loop until this block done + +LAB_1F07 + DEC Adatah ; decrement array pointer high byte + DEC Aspth ; decrement block count high byte + BNE LAB_1F02 ; loop until all blocks done + + INC Adatah ; correct for last loop + SEC ; set carry for subtract + LDY #$02 ; index to array size low byte + LDA Earryl ; get array mem end low byte + SBC Astrtl ; subtract array start low byte + STA (Astrtl),Y ; save array size low byte + INY ; index to array size high byte + LDA Earryh ; get array mem end high byte + SBC Astrth ; subtract array start high byte + STA (Astrtl),Y ; save array size high byte + LDA Defdim ; get default DIM flag + BNE LAB_1F7B ; exit (RET) if this was a DIM command + + ; else, find element + INY ; index to # of dimensions + +LAB_1F24 + LDA (Astrtl),Y ; get array's dimension count + STA Dimcnt ; save it + +; we have found, or built, the array. now we need to find the element + +LAB_1F28 + LDA #$00 ; clear byte + STA Asptl ; clear array data pointer low byte +LAB_1F2C + STA Aspth ; save array data pointer high byte + INY ; increment index (point to array bound high byte) + PLA ; pull array index low byte + TAX ; copy to X + STA FAC1_2 ; save index low byte to FAC1 mantissa2 + PLA ; pull array index high byte + STA FAC1_3 ; save index high byte to FAC1 mantissa3 + CMP (Astrtl),Y ; compare with array bound high byte + BCC LAB_1F48 ; branch if within bounds + + BNE LAB_1F42 ; if outside bounds do array bounds error + + ; else high byte was = so test low bytes + INY ; index to array bound low byte + TXA ; get array index low byte + CMP (Astrtl),Y ; compare with array bound low byte + BCC LAB_1F49 ; branch if within bounds + +LAB_1F42 + JMP LAB_1E85 ; else do array bounds error + +LAB_1F45 + JMP LAB_OMER ; do "Out of memory" error then warm start + +LAB_1F48 + INY ; index to array bound low byte +LAB_1F49 + LDA Aspth ; get array data pointer high byte + ORA Asptl ; OR with array data pointer low byte + BEQ LAB_1F5A ; branch if array data pointer = null (skip multiply) + + JSR LAB_1F7C ; does XY = (Astrtl),Y * (Asptl) + TXA ; get result low byte + ADC FAC1_2 ; add index low byte from FAC1 mantissa2 + TAX ; save result low byte + TYA ; get result high byte + LDY ut1_pl ; restore index +LAB_1F5A + ADC FAC1_3 ; add index high byte from FAC1 mantissa3 + STX Asptl ; save array data pointer low byte + DEC Dimcnt ; decrement dimensions count + BNE LAB_1F2C ; loop if dimensions still to do + + ASL Asptl ; array data pointer low byte * 2 + ROL ; array data pointer high byte * 2 + ASL Asptl ; array data pointer low byte * 4 + ROL ; array data pointer high byte * 4 + TAY ; copy high byte + LDA Asptl ; get low byte + ADC Adatal ; add array data start pointer low byte + STA Cvaral ; save as current var address low byte + TYA ; get high byte back + ADC Adatah ; add array data start pointer high byte + STA Cvarah ; save as current var address high byte + TAY ; copy high byte to Y + LDA Cvaral ; get current var address low byte +LAB_1F7B + RTS + +; does XY = (Astrtl),Y * (Asptl) + +LAB_1F7C + STY ut1_pl ; save index + LDA (Astrtl),Y ; get dimension size low byte + STA dims_l ; save dimension size low byte + DEY ; decrement index + LDA (Astrtl),Y ; get dimension size high byte + STA dims_h ; save dimension size high byte + + LDA #$10 ; count = $10 (16 bit multiply) + STA numbit ; save bit count + LDX #$00 ; clear result low byte + LDY #$00 ; clear result high byte +LAB_1F8F + TXA ; get result low byte + ASL ; *2 + TAX ; save result low byte + TYA ; get result high byte + ROL ; *2 + TAY ; save result high byte + BCS LAB_1F45 ; if overflow go do "Out of memory" error + + ASL Asptl ; shift multiplier low byte + ROL Aspth ; shift multiplier high byte + BCC LAB_1FA8 ; skip add if no carry + + CLC ; else clear carry for add + TXA ; get result low byte + ADC dims_l ; add dimension size low byte + TAX ; save result low byte + TYA ; get result high byte + ADC dims_h ; add dimension size high byte + TAY ; save result high byte + BCS LAB_1F45 ; if overflow go do "Out of memory" error + +LAB_1FA8 + DEC numbit ; decrement bit count + BNE LAB_1F8F ; loop until all done + + RTS + +; perform FRE() + +LAB_FRE + LDA Dtypef ; get data type flag, $FF=string, $00=numeric + BPL LAB_1FB4 ; branch if numeric + + JSR LAB_22B6 ; pop string off descriptor stack, or from top of string + ; space returns with A = length, X=$71=pointer low byte, + ; Y=$72=pointer high byte + + ; FRE(n) was numeric so do this +LAB_1FB4 + JSR LAB_GARB ; go do garbage collection + SEC ; set carry for subtract + LDA Sstorl ; get bottom of string space low byte + SBC Earryl ; subtract array mem end low byte + TAY ; copy result to Y + LDA Sstorh ; get bottom of string space high byte + SBC Earryh ; subtract array mem end high byte + +; save and convert integer AY to FAC1 + +LAB_AYFC + LSR Dtypef ; clear data type flag, $FF=string, $00=numeric + STA FAC1_1 ; save FAC1 mantissa1 + STY FAC1_2 ; save FAC1 mantissa2 + LDX #$90 ; set exponent=2^16 (integer) + JMP LAB_27E3 ; set exp=X, clear FAC1_3, normalise and return + +; perform POS() + +LAB_POS + LDY TPos ; get terminal position + +; convert Y to byte in FAC1 + +LAB_1FD0 + LDA #$00 ; clear high byte + BEQ LAB_AYFC ; always save and convert integer AY to FAC1 and return + +; check not Direct (used by DEF and INPUT) + +LAB_CKRN + LDX Clineh ; get current line high byte + INX ; increment it + BNE LAB_1F7B ; return if can continue not direct mode + + ; else do illegal direct error +LAB_1FD9 + LDX #$16 ; error code $16 ("Illegal direct" error) +LAB_1FDB + JMP LAB_XERR ; go do error #X, then warm start + +; perform DEF + +LAB_DEF + JSR LAB_200B ; check FNx syntax + STA func_l ; save function pointer low byte + STY func_h ; save function pointer high byte + JSR LAB_CKRN ; check not Direct (back here if ok) + JSR LAB_1BFE ; scan for "(" , else do syntax error then warm start + LDA #$80 ; set flag for FNx + STA Sufnxf ; save subscript/FNx flag + JSR LAB_GVAR ; get (var) address + JSR LAB_CTNM ; check if source is numeric, else do type mismatch + JSR LAB_1BFB ; scan for ")" , else do syntax error then warm start + LDA #TK_EQUAL ; get = token + JSR LAB_SCCA ; scan for CHR$(A), else do syntax error then warm start + LDA Cvarah ; get current var address high byte + PHA ; push it + LDA Cvaral ; get current var address low byte + PHA ; push it + LDA Bpntrh ; get BASIC execute pointer high byte + PHA ; push it + LDA Bpntrl ; get BASIC execute pointer low byte + PHA ; push it + JSR LAB_DATA ; go perform DATA + JMP LAB_207A ; put execute pointer and variable pointer into function + ; and return + +; check FNx syntax + +LAB_200B + LDA #TK_FN ; get FN" token + JSR LAB_SCCA ; scan for CHR$(A) , else do syntax error then warm start + ; return character after A + ORA #$80 ; set FN flag bit + STA Sufnxf ; save FN flag so array variable test fails + JSR LAB_1D12 ; search for FN variable + JMP LAB_CTNM ; check if source is numeric and return, else do type + ; mismatch + + ; Evaluate FNx +LAB_201E + JSR LAB_200B ; check FNx syntax + PHA ; push function pointer low byte + TYA ; copy function pointer high byte + PHA ; push function pointer high byte + JSR LAB_1BFE ; scan for "(", else do syntax error then warm start + JSR LAB_EVEX ; evaluate expression + JSR LAB_1BFB ; scan for ")", else do syntax error then warm start + JSR LAB_CTNM ; check if source is numeric, else do type mismatch + PLA ; pop function pointer high byte + STA func_h ; restore it + PLA ; pop function pointer low byte + STA func_l ; restore it + LDX #$20 ; error code $20 ("Undefined function" error) + LDY #$03 ; index to variable pointer high byte + LDA (func_l),Y ; get variable pointer high byte + BEQ LAB_1FDB ; if zero go do undefined function error + + STA Cvarah ; save variable address high byte + DEY ; index to variable address low byte + LDA (func_l),Y ; get variable address low byte + STA Cvaral ; save variable address low byte + TAX ; copy address low byte + + ; now stack the function variable value before use + INY ; index to mantissa_3 +LAB_2043 + LDA (Cvaral),Y ; get byte from variable + PHA ; stack it + DEY ; decrement index + BPL LAB_2043 ; loop until variable stacked + + LDY Cvarah ; get variable address high byte + JSR LAB_2778 ; pack FAC1 (function expression value) into (XY) + ; (function variable), return Y=0, always + LDA Bpntrh ; get BASIC execute pointer high byte + PHA ; push it + LDA Bpntrl ; get BASIC execute pointer low byte + PHA ; push it + LDA (func_l),Y ; get function execute pointer low byte + STA Bpntrl ; save as BASIC execute pointer low byte + INY ; index to high byte + LDA (func_l),Y ; get function execute pointer high byte + STA Bpntrh ; save as BASIC execute pointer high byte + LDA Cvarah ; get variable address high byte + PHA ; push it + LDA Cvaral ; get variable address low byte + PHA ; push it + JSR LAB_EVNM ; evaluate expression and check is numeric, + ; else do type mismatch + PLA ; pull variable address low byte + STA func_l ; save variable address low byte + PLA ; pull variable address high byte + STA func_h ; save variable address high byte + JSR LAB_GBYT ; scan memory + BEQ LAB_2074 ; branch if null (should be [EOL] marker) + + JMP LAB_SNER ; else syntax error then warm start + +; restore Bpntrl,Bpntrh and function variable from stack + +LAB_2074 + PLA ; pull BASIC execute pointer low byte + STA Bpntrl ; restore BASIC execute pointer low byte + PLA ; pull BASIC execute pointer high byte + STA Bpntrh ; restore BASIC execute pointer high byte + +; put execute pointer and variable pointer into function + +LAB_207A + LDY #$00 ; clear index + PLA ; pull BASIC execute pointer low byte + STA (func_l),Y ; save to function + INY ; increment index + PLA ; pull BASIC execute pointer high byte + STA (func_l),Y ; save to function + INY ; increment index + PLA ; pull current var address low byte + STA (func_l),Y ; save to function + INY ; increment index + PLA ; pull current var address high byte + STA (func_l),Y ; save to function + RTS + +; perform STR$() + +LAB_STRS + JSR LAB_CTNM ; check if source is numeric, else do type mismatch + JSR LAB_296E ; convert FAC1 to string + LDA #Decssp1 ; set result string high pointer + BEQ LAB_20AE ; print null terminated string to Sutill/Sutilh + +; Do string vector +; copy des_pl/h to des_2l/h and make string space A bytes long + +LAB_209C + LDX des_pl ; get descriptor pointer low byte + LDY des_ph ; get descriptor pointer high byte + STX des_2l ; save descriptor pointer low byte + STY des_2h ; save descriptor pointer high byte + +; make string space A bytes long +; A=length, X=Sutill=ptr low byte, Y=Sutilh=ptr high byte + +LAB_MSSP + JSR LAB_2115 ; make space in string memory for string A long + ; return X=Sutill=ptr low byte, Y=Sutilh=ptr high byte + STX str_pl ; save string pointer low byte + STY str_ph ; save string pointer high byte + STA str_ln ; save length + RTS + +; Scan, set up string +; print " terminated string to Sutill/Sutilh + +LAB_20AE + LDX #$22 ; set terminator to " + STX Srchc ; set search character (terminator 1) + STX Asrch ; set terminator 2 + +; print [Srchc] or [Asrch] terminated string to Sutill/Sutilh +; source is AY + +LAB_20B4 + STA ssptr_l ; store string start low byte + STY ssptr_h ; store string start high byte + STA str_pl ; save string pointer low byte + STY str_ph ; save string pointer high byte + LDY #$FF ; set length to -1 +LAB_20BE + INY ; increment length + LDA (ssptr_l),Y ; get byte from string + BEQ LAB_20CF ; exit loop if null byte [EOS] + + CMP Srchc ; compare with search character (terminator 1) + BEQ LAB_20CB ; branch if terminator + + CMP Asrch ; compare with terminator 2 + BNE LAB_20BE ; loop if not terminator 2 + +LAB_20CB + CMP #$22 ; compare with " + BEQ LAB_20D0 ; branch if " (carry set if = !) + +LAB_20CF + CLC ; clear carry for add (only if [EOL] terminated string) +LAB_20D0 + STY str_ln ; save length in FAC1 exponent + TYA ; copy length to A + ADC ssptr_l ; add string start low byte + STA Sendl ; save string end low byte + LDX ssptr_h ; get string start high byte + BCC LAB_20DC ; branch if no low byte overflow + + INX ; else increment high byte +LAB_20DC + STX Sendh ; save string end high byte + LDA ssptr_h ; get string start high byte + CMP #>Ram_base ; compare with start of program memory + BCS LAB_RTST ; branch if not in utility area + + ; string in utility area, move to string memory + TYA ; copy length to A + JSR LAB_209C ; copy des_pl/h to des_2l/h and make string space A bytes + ; long + LDX ssptr_l ; get string start low byte + LDY ssptr_h ; get string start high byte + JSR LAB_2298 ; store string A bytes long from XY to (Sutill) + +; check for space on descriptor stack then .. +; put string address and length on descriptor stack and update stack pointers + +LAB_RTST + LDX next_s ; get string stack pointer + CPX #des_sk+$09 ; compare with max+1 + BNE LAB_20F8 ; branch if space on string stack + + ; else do string too complex error + LDX #$1C ; error code $1C ("String too complex" error) +LAB_20F5 + JMP LAB_XERR ; do error #X, then warm start + +; put string address and length on descriptor stack and update stack pointers + +LAB_20F8 + LDA str_ln ; get string length + STA PLUS_0,X ; put on string stack + LDA str_pl ; get string pointer low byte + STA PLUS_1,X ; put on string stack + LDA str_ph ; get string pointer high byte + STA PLUS_2,X ; put on string stack + LDY #$00 ; clear Y + STX des_pl ; save string descriptor pointer low byte + STY des_ph ; save string descriptor pointer high byte (always $00) + DEY ; Y = $FF + STY Dtypef ; save data type flag, $FF=string + STX last_sl ; save old stack pointer (current top item) + INX ; update stack pointer + INX ; update stack pointer + INX ; update stack pointer + STX next_s ; save new top item value + RTS + +; Build descriptor +; make space in string memory for string A long +; return X=Sutill=ptr low byte, Y=Sutill=ptr high byte + +LAB_2115 + LSR Gclctd ; clear garbage collected flag (b7) + + ; make space for string A long +LAB_2117 + PHA ; save string length + EOR #$FF ; complement it + SEC ; set carry for subtract (twos comp add) + ADC Sstorl ; add bottom of string space low byte (subtract length) + LDY Sstorh ; get bottom of string space high byte + BCS LAB_2122 ; skip decrement if no underflow + + DEY ; decrement bottom of string space high byte +LAB_2122 + CPY Earryh ; compare with array mem end high byte + BCC LAB_2137 ; do out of memory error if less + + BNE LAB_212C ; if not = skip next test + + CMP Earryl ; compare with array mem end low byte + BCC LAB_2137 ; do out of memory error if less + +LAB_212C + STA Sstorl ; save bottom of string space low byte + STY Sstorh ; save bottom of string space high byte + STA Sutill ; save string utility ptr low byte + STY Sutilh ; save string utility ptr high byte + TAX ; copy low byte to X + PLA ; get string length back + RTS + +LAB_2137 + LDX #$0C ; error code $0C ("Out of memory" error) + LDA Gclctd ; get garbage collected flag + BMI LAB_20F5 ; if set then do error code X + + JSR LAB_GARB ; else go do garbage collection + LDA #$80 ; flag for garbage collected + STA Gclctd ; set garbage collected flag + PLA ; pull length + BNE LAB_2117 ; go try again (loop always, length should never be = $00) + +; garbage collection routine + +LAB_GARB + LDX Ememl ; get end of mem low byte + LDA Ememh ; get end of mem high byte + +; re-run routine from last ending + +LAB_214B + STX Sstorl ; set string storage low byte + STA Sstorh ; set string storage high byte + LDY #$00 ; clear index + STY garb_h ; clear working pointer high byte (flag no strings to move) + LDA Earryl ; get array mem end low byte + LDX Earryh ; get array mem end high byte + STA Histrl ; save as highest string low byte + STX Histrh ; save as highest string high byte + LDA #des_sk ; set descriptor stack pointer + STA ut1_pl ; save descriptor stack pointer low byte + STY ut1_ph ; save descriptor stack pointer high byte ($00) +LAB_2161 + CMP next_s ; compare with descriptor stack pointer + BEQ LAB_216A ; branch if = + + JSR LAB_21D7 ; go garbage collect descriptor stack + BEQ LAB_2161 ; loop always + + ; done stacked strings, now do string vars +LAB_216A + ASL g_step ; set step size = $06 + LDA Svarl ; get start of vars low byte + LDX Svarh ; get start of vars high byte + STA ut1_pl ; save as pointer low byte + STX ut1_ph ; save as pointer high byte +LAB_2176 + CPX Sarryh ; compare start of arrays high byte + BNE LAB_217E ; branch if no high byte match + + CMP Sarryl ; else compare start of arrays low byte + BEQ LAB_2183 ; branch if = var mem end + +LAB_217E + JSR LAB_21D1 ; go garbage collect strings + BEQ LAB_2176 ; loop always + + ; done string vars, now do string arrays +LAB_2183 + STA Nbendl ; save start of arrays low byte as working pointer + STX Nbendh ; save start of arrays high byte as working pointer + LDA #$04 ; set step size + STA g_step ; save step size +LAB_218B + LDA Nbendl ; get pointer low byte + LDX Nbendh ; get pointer high byte +LAB_218F + CPX Earryh ; compare with array mem end high byte + BNE LAB_219A ; branch if not at end + + CMP Earryl ; else compare with array mem end low byte + BEQ LAB_2216 ; tidy up and exit if at end + +LAB_219A + STA ut1_pl ; save pointer low byte + STX ut1_ph ; save pointer high byte + LDY #$02 ; set index + LDA (ut1_pl),Y ; get array size low byte + ADC Nbendl ; add start of this array low byte + STA Nbendl ; save start of next array low byte + INY ; increment index + LDA (ut1_pl),Y ; get array size high byte + ADC Nbendh ; add start of this array high byte + STA Nbendh ; save start of next array high byte + LDY #$01 ; set index + LDA (ut1_pl),Y ; get name second byte + BPL LAB_218B ; skip if not string array + +; was string array so .. + + LDY #$04 ; set index + LDA (ut1_pl),Y ; get # of dimensions + ASL ; *2 + ADC #$05 ; +5 (array header size) + JSR LAB_2208 ; go set up for first element +LAB_21C4 + CPX Nbendh ; compare with start of next array high byte + BNE LAB_21CC ; branch if <> (go do this array) + + CMP Nbendl ; else compare element pointer low byte with next array + ; low byte + BEQ LAB_218F ; if equal then go do next array + +LAB_21CC + JSR LAB_21D7 ; go defrag array strings + BEQ LAB_21C4 ; go do next array string (loop always) + +; defrag string variables +; enter with XA = variable pointer +; return with XA = next variable pointer + +LAB_21D1 + INY ; increment index (Y was $00) + LDA (ut1_pl),Y ; get var name byte 2 + BPL LAB_2206 ; if not string, step pointer to next var and return + + INY ; else increment index +LAB_21D7 + LDA (ut1_pl),Y ; get string length + BEQ LAB_2206 ; if null, step pointer to next string and return + + INY ; else increment index + LDA (ut1_pl),Y ; get string pointer low byte + TAX ; copy to X + INY ; increment index + LDA (ut1_pl),Y ; get string pointer high byte + CMP Sstorh ; compare bottom of string space high byte + BCC LAB_21EC ; branch if less + + BNE LAB_2206 ; if greater, step pointer to next string and return + + ; high bytes were = so compare low bytes + CPX Sstorl ; compare bottom of string space low byte + BCS LAB_2206 ; if >=, step pointer to next string and return + + ; string pointer is < string storage pointer (pos in mem) +LAB_21EC + CMP Histrh ; compare to highest string high byte + BCC LAB_2207 ; if <, step pointer to next string and return + + BNE LAB_21F6 ; if > update pointers, step to next and return + + ; high bytes were = so compare low bytes + CPX Histrl ; compare to highest string low byte + BCC LAB_2207 ; if <, step pointer to next string and return + + ; string is in string memory space +LAB_21F6 + STX Histrl ; save as new highest string low byte + STA Histrh ; save as new highest string high byte + LDA ut1_pl ; get start of vars(descriptors) low byte + LDX ut1_ph ; get start of vars(descriptors) high byte + STA garb_l ; save as working pointer low byte + STX garb_h ; save as working pointer high byte + DEY ; decrement index DIFFERS + DEY ; decrement index (should point to descriptor start) + STY g_indx ; save index pointer + + ; step pointer to next string +LAB_2206 + CLC ; clear carry for add +LAB_2207 + LDA g_step ; get step size +LAB_2208 + ADC ut1_pl ; add pointer low byte + STA ut1_pl ; save pointer low byte + BCC LAB_2211 ; branch if no overflow + + INC ut1_ph ; else increment high byte +LAB_2211 + LDX ut1_ph ; get pointer high byte + LDY #$00 ; clear Y + RTS + +; search complete, now either exit or set-up and move string + +LAB_2216 + DEC g_step ; decrement step size (now $03 for descriptor stack) + LDX garb_h ; get string to move high byte + BEQ LAB_2211 ; exit if nothing to move + + LDY g_indx ; get index byte back (points to descriptor) + CLC ; clear carry for add + LDA (garb_l),Y ; get string length + ADC Histrl ; add highest string low byte + STA Obendl ; save old block end low pointer + LDA Histrh ; get highest string high byte + ADC #$00 ; add any carry + STA Obendh ; save old block end high byte + LDA Sstorl ; get bottom of string space low byte + LDX Sstorh ; get bottom of string space high byte + STA Nbendl ; save new block end low byte + STX Nbendh ; save new block end high byte + JSR LAB_11D6 ; open up space in memory, don't set array end + LDY g_indx ; get index byte + INY ; point to descriptor low byte + LDA Nbendl ; get string pointer low byte + STA (garb_l),Y ; save new string pointer low byte + TAX ; copy string pointer low byte + INC Nbendh ; correct high byte (move sets high byte -1) + LDA Nbendh ; get new string pointer high byte + INY ; point to descriptor high byte + STA (garb_l),Y ; save new string pointer high byte + JMP LAB_214B ; re-run routine from last ending + ; (but don't collect this string) + +; concatenate +; add strings, string 1 is in descriptor des_pl, string 2 is in line + +LAB_224D + LDA des_ph ; get descriptor pointer high byte + PHA ; put on stack + LDA des_pl ; get descriptor pointer low byte + PHA ; put on stack + JSR LAB_GVAL ; get value from line + JSR LAB_CTST ; check if source is string, else do type mismatch + PLA ; get descriptor pointer low byte back + STA ssptr_l ; set pointer low byte + PLA ; get descriptor pointer high byte back + STA ssptr_h ; set pointer high byte + LDY #$00 ; clear index + LDA (ssptr_l),Y ; get length_1 from descriptor + CLC ; clear carry for add + ADC (des_pl),Y ; add length_2 + BCC LAB_226D ; branch if no overflow + + LDX #$1A ; else set error code $1A ("String too long" error) + JMP LAB_XERR ; do error #X, then warm start + +LAB_226D + JSR LAB_209C ; copy des_pl/h to des_2l/h and make string space A bytes + ; long + JSR LAB_228A ; copy string from descriptor (sdescr) to (Sutill) + LDA des_2l ; get descriptor pointer low byte + LDY des_2h ; get descriptor pointer high byte + JSR LAB_22BA ; pop (YA) descriptor off stack or from top of string space + ; returns with A = length, ut1_pl = pointer low byte, + ; ut1_ph = pointer high byte + JSR LAB_229C ; store string A bytes long from (ut1_pl) to (Sutill) + LDA ssptr_l ;.set descriptor pointer low byte + LDY ssptr_h ;.set descriptor pointer high byte + JSR LAB_22BA ; pop (YA) descriptor off stack or from top of string space + ; returns with A = length, X=ut1_pl=pointer low byte, + ; Y=ut1_ph=pointer high byte + JSR LAB_RTST ; check for space on descriptor stack then put string + ; address and length on descriptor stack and update stack + ; pointers + JMP LAB_1ADB ;.continue evaluation + +; copy string from descriptor (sdescr) to (Sutill) + +LAB_228A + LDY #$00 ; clear index + LDA (sdescr),Y ; get string length + PHA ; save on stack + INY ; increment index + LDA (sdescr),Y ; get source string pointer low byte + TAX ; copy to X + INY ; increment index + LDA (sdescr),Y ; get source string pointer high byte + TAY ; copy to Y + PLA ; get length back + +; store string A bytes long from YX to (Sutill) + +LAB_2298 + STX ut1_pl ; save source string pointer low byte + STY ut1_ph ; save source string pointer high byte + +; store string A bytes long from (ut1_pl) to (Sutill) + +LAB_229C + TAX ; copy length to index (don't count with Y) + BEQ LAB_22B2 ; branch if = $0 (null string) no need to add zero length + + LDY #$00 ; zero pointer (copy forward) +LAB_22A0 + LDA (ut1_pl),Y ; get source byte + STA (Sutill),Y ; save destination byte + + INY ; increment index + DEX ; decrement counter + BNE LAB_22A0 ; loop while <> 0 + + TYA ; restore length from Y +LAB_22A9 + CLC ; clear carry for add + ADC Sutill ; add string utility ptr low byte + STA Sutill ; save string utility ptr low byte + BCC LAB_22B2 ; branch if no carry + + INC Sutilh ; else increment string utility ptr high byte +LAB_22B2 + RTS + +; evaluate string + +LAB_EVST + JSR LAB_CTST ; check if source is string, else do type mismatch + +; pop string off descriptor stack, or from top of string space +; returns with A = length, X=pointer low byte, Y=pointer high byte + +LAB_22B6 + LDA des_pl ; get descriptor pointer low byte + LDY des_ph ; get descriptor pointer high byte + +; pop (YA) descriptor off stack or from top of string space +; returns with A = length, X=ut1_pl=pointer low byte, Y=ut1_ph=pointer high byte + +LAB_22BA + STA ut1_pl ; save descriptor pointer low byte + STY ut1_ph ; save descriptor pointer high byte + JSR LAB_22EB ; clean descriptor stack, YA = pointer + PHP ; save status flags + LDY #$00 ; clear index + LDA (ut1_pl),Y ; get length from string descriptor + PHA ; put on stack + INY ; increment index + LDA (ut1_pl),Y ; get string pointer low byte from descriptor + TAX ; copy to X + INY ; increment index + LDA (ut1_pl),Y ; get string pointer high byte from descriptor + TAY ; copy to Y + PLA ; get string length back + PLP ; restore status + BNE LAB_22E6 ; branch if pointer <> last_sl,last_sh + + CPY Sstorh ; compare bottom of string space high byte + BNE LAB_22E6 ; branch if <> + + CPX Sstorl ; else compare bottom of string space low byte + BNE LAB_22E6 ; branch if <> + + PHA ; save string length + CLC ; clear carry for add + ADC Sstorl ; add bottom of string space low byte + STA Sstorl ; save bottom of string space low byte + BCC LAB_22E5 ; skip increment if no overflow + + INC Sstorh ; increment bottom of string space high byte +LAB_22E5 + PLA ; restore string length +LAB_22E6 + STX ut1_pl ; save string pointer low byte + STY ut1_ph ; save string pointer high byte + RTS + +; clean descriptor stack, YA = pointer +; checks if AY is on the descriptor stack, if so does a stack discard + +LAB_22EB + CPY last_sh ; compare pointer high byte + BNE LAB_22FB ; exit if <> + + CMP last_sl ; compare pointer low byte + BNE LAB_22FB ; exit if <> + + STA next_s ; save descriptor stack pointer + SBC #$03 ; -3 + STA last_sl ; save low byte -3 + LDY #$00 ; clear high byte +LAB_22FB + RTS + +; perform CHR$() + +LAB_CHRS + JSR LAB_EVBY ; evaluate byte expression, result in X + TXA ; copy to A + PHA ; save character + LDA #$01 ; string is single byte + JSR LAB_MSSP ; make string space A bytes long A=$AC=length, + ; X=$AD=Sutill=ptr low byte, Y=$AE=Sutilh=ptr high byte + PLA ; get character back + LDY #$00 ; clear index + STA (str_pl),Y ; save byte in string (byte IS string!) + JMP LAB_RTST ; check for space on descriptor stack then put string + ; address and length on descriptor stack and update stack + ; pointers + +; perform LEFT$() + +LAB_LEFT + PHA ; push byte parameter + JSR LAB_236F ; pull string data and byte parameter from stack + ; return pointer in des_2l/h, byte in A (and X), Y=0 + CMP (des_2l),Y ; compare byte parameter with string length + TYA ; clear A + BEQ LAB_2316 ; go do string copy (branch always) + +; perform RIGHT$() + +LAB_RIGHT + PHA ; push byte parameter + JSR LAB_236F ; pull string data and byte parameter from stack + ; return pointer in des_2l/h, byte in A (and X), Y=0 + CLC ; clear carry for add-1 + SBC (des_2l),Y ; subtract string length + EOR #$FF ; invert it (A=LEN(expression$)-l) + +LAB_2316 + BCC LAB_231C ; branch if string length > byte parameter + + LDA (des_2l),Y ; else make parameter = length + TAX ; copy to byte parameter copy + TYA ; clear string start offset +LAB_231C + PHA ; save string start offset +LAB_231D + TXA ; copy byte parameter (or string length if <) +LAB_231E + PHA ; save string length + JSR LAB_MSSP ; make string space A bytes long A=$AC=length, + ; X=$AD=Sutill=ptr low byte, Y=$AE=Sutilh=ptr high byte + LDA des_2l ; get descriptor pointer low byte + LDY des_2h ; get descriptor pointer high byte + JSR LAB_22BA ; pop (YA) descriptor off stack or from top of string space + ; returns with A = length, X=ut1_pl=pointer low byte, + ; Y=ut1_ph=pointer high byte + PLA ; get string length back + TAY ; copy length to Y + PLA ; get string start offset back + CLC ; clear carry for add + ADC ut1_pl ; add start offset to string start pointer low byte + STA ut1_pl ; save string start pointer low byte + BCC LAB_2335 ; branch if no overflow + + INC ut1_ph ; else increment string start pointer high byte +LAB_2335 + TYA ; copy length to A + JSR LAB_229C ; store string A bytes long from (ut1_pl) to (Sutill) + JMP LAB_RTST ; check for space on descriptor stack then put string + ; address and length on descriptor stack and update stack + ; pointers + +; perform MID$() + +LAB_MIDS + PHA ; push byte parameter + LDA #$FF ; set default length = 255 + STA mids_l ; save default length + JSR LAB_GBYT ; scan memory + CMP #')' ; compare with ")" + BEQ LAB_2358 ; branch if = ")" (skip second byte get) + + JSR LAB_1C01 ; scan for "," , else do syntax error then warm start + JSR LAB_GTBY ; get byte parameter (use copy in mids_l) +LAB_2358 + JSR LAB_236F ; pull string data and byte parameter from stack + ; return pointer in des_2l/h, byte in A (and X), Y=0 + DEX ; decrement start index + TXA ; copy to A + PHA ; save string start offset + CLC ; clear carry for sub-1 + LDX #$00 ; clear output string length + SBC (des_2l),Y ; subtract string length + BCS LAB_231D ; if start>string length go do null string + + EOR #$FF ; complement -length + CMP mids_l ; compare byte parameter + BCC LAB_231E ; if length>remaining string go do RIGHT$ + + LDA mids_l ; get length byte + BCS LAB_231E ; go do string copy (branch always) + +; pull string data and byte parameter from stack +; return pointer in des_2l/h, byte in A (and X), Y=0 + +LAB_236F + JSR LAB_1BFB ; scan for ")" , else do syntax error then warm start + PLA ; pull return address low byte (return address) + STA Fnxjpl ; save functions jump vector low byte + PLA ; pull return address high byte (return address) + STA Fnxjph ; save functions jump vector high byte + PLA ; pull byte parameter + TAX ; copy byte parameter to X + PLA ; pull string pointer low byte + STA des_2l ; save it + PLA ; pull string pointer high byte + STA des_2h ; save it + LDY #$00 ; clear index + TXA ; copy byte parameter + BEQ LAB_23A8 ; if null do function call error then warm start + + INC Fnxjpl ; increment function jump vector low byte + ; (JSR pushes return addr-1. this is all very nice + ; but will go tits up if either call is on a page + ; boundary!) + JMP (Fnxjpl) ; in effect, RTS + +; perform LCASE$() + +LAB_LCASE + JSR LAB_EVST ; evaluate string + STA str_ln ; set string length + TAY ; copy length to Y + BEQ NoString ; branch if null string + + JSR LAB_MSSP ; make string space A bytes long A=length, + ; X=Sutill=ptr low byte, Y=Sutilh=ptr high byte + STX str_pl ; save string pointer low byte + STY str_ph ; save string pointer high byte + TAY ; get string length back + +LC_loop + DEY ; decrement index + LDA (ut1_pl),Y ; get byte from string + JSR LAB_1D82 ; is character "A" to "Z" + BCC NoUcase ; branch if not upper case alpha + + ORA #$20 ; convert upper to lower case +NoUcase + STA (Sutill),Y ; save byte back to string + TYA ; test index + BNE LC_loop ; loop if not all done + + BEQ NoString ; tidy up and exit, branch always + +; perform UCASE$() + +LAB_UCASE + JSR LAB_EVST ; evaluate string + STA str_ln ; set string length + TAY ; copy length to Y + BEQ NoString ; branch if null string + + JSR LAB_MSSP ; make string space A bytes long A=length, + ; X=Sutill=ptr low byte, Y=Sutilh=ptr high byte + STX str_pl ; save string pointer low byte + STY str_ph ; save string pointer high byte + TAY ; get string length back + +UC_loop + DEY ; decrement index + LDA (ut1_pl),Y ; get byte from string + JSR LAB_CASC ; is character "a" to "z" (or "A" to "Z") + BCC NoLcase ; branch if not alpha + + AND #$DF ; convert lower to upper case +NoLcase + STA (Sutill),Y ; save byte back to string + TYA ; test index + BNE UC_loop ; loop if not all done + +NoString + JMP LAB_RTST ; check for space on descriptor stack then put string + ; address and length on descriptor stack and update stack + ; pointers + +; perform SADD() + +LAB_SADD + JSR LAB_IGBY ; increment and scan memory + JSR LAB_GVAR ; get var address + + JSR LAB_1BFB ; scan for ")", else do syntax error then warm start + JSR LAB_CTST ; check if source is string, else do type mismatch + + LDY #$02 ; index to string pointer high byte + LDA (Cvaral),Y ; get string pointer high byte + TAX ; copy string pointer high byte to X + DEY ; index to string pointer low byte + LDA (Cvaral),Y ; get string pointer low byte + TAY ; copy string pointer low byte to Y + TXA ; copy string pointer high byte to A + JMP LAB_AYFC ; save and convert integer AY to FAC1 and return + +; perform LEN() + +LAB_LENS + JSR LAB_ESGL ; evaluate string, get length in A (and Y) + JMP LAB_1FD0 ; convert Y to byte in FAC1 and return + +; evaluate string, get length in Y + +LAB_ESGL + JSR LAB_EVST ; evaluate string + TAY ; copy length to Y + RTS + +; perform ASC() + +LAB_ASC + JSR LAB_ESGL ; evaluate string, get length in A (and Y) + BEQ LAB_23A8 ; if null do function call error then warm start + + LDY #$00 ; set index to first character + LDA (ut1_pl),Y ; get byte + TAY ; copy to Y + JMP LAB_1FD0 ; convert Y to byte in FAC1 and return + +; do function call error then warm start + +LAB_23A8 + JMP LAB_FCER ; do function call error then warm start + +; scan and get byte parameter + +LAB_SGBY + JSR LAB_IGBY ; increment and scan memory + +; get byte parameter + +LAB_GTBY + JSR LAB_EVNM ; evaluate expression and check is numeric, + ; else do type mismatch + +; evaluate byte expression, result in X + +LAB_EVBY + JSR LAB_EVPI ; evaluate integer expression (no check) + + LDY FAC1_2 ; get FAC1 mantissa2 + BNE LAB_23A8 ; if top byte <> 0 do function call error then warm start + + LDX FAC1_3 ; get FAC1 mantissa3 + JMP LAB_GBYT ; scan memory and return + +; perform VAL() + +LAB_VAL + JSR LAB_ESGL ; evaluate string, get length in A (and Y) + BNE LAB_23C5 ; branch if not null string + + ; string was null so set result = $00 + JMP LAB_24F1 ; clear FAC1 exponent and sign and return + +LAB_23C5 + LDX Bpntrl ; get BASIC execute pointer low byte + LDY Bpntrh ; get BASIC execute pointer high byte + STX Btmpl ; save BASIC execute pointer low byte + STY Btmph ; save BASIC execute pointer high byte + LDX ut1_pl ; get string pointer low byte + STX Bpntrl ; save as BASIC execute pointer low byte + CLC ; clear carry + ADC ut1_pl ; add string length + STA ut2_pl ; save string end low byte + LDA ut1_ph ; get string pointer high byte + STA Bpntrh ; save as BASIC execute pointer high byte + ADC #$00 ; add carry to high byte + STA ut2_ph ; save string end high byte + LDY #$00 ; set index to $00 + LDA (ut2_pl),Y ; get string end +1 byte + PHA ; push it + TYA ; clear A + STA (ut2_pl),Y ; terminate string with $00 + JSR LAB_GBYT ; scan memory + JSR LAB_2887 ; get FAC1 from string + PLA ; restore string end +1 byte + LDY #$00 ; set index to zero + STA (ut2_pl),Y ; put string end byte back + +; restore BASIC execute pointer from temp (Btmpl/Btmph) + +LAB_23F3 + LDX Btmpl ; get BASIC execute pointer low byte back + LDY Btmph ; get BASIC execute pointer high byte back + STX Bpntrl ; save BASIC execute pointer low byte + STY Bpntrh ; save BASIC execute pointer high byte + RTS + +; get two parameters for POKE or WAIT + +LAB_GADB + JSR LAB_EVNM ; evaluate expression and check is numeric, + ; else do type mismatch + JSR LAB_F2FX ; save integer part of FAC1 in temporary integer + +; scan for "," and get byte, else do Syntax error then warm start + +LAB_SCGB + JSR LAB_1C01 ; scan for "," , else do syntax error then warm start + LDA Itemph ; save temporary integer high byte + PHA ; on stack + LDA Itempl ; save temporary integer low byte + PHA ; on stack + JSR LAB_GTBY ; get byte parameter + PLA ; pull low byte + STA Itempl ; restore temporary integer low byte + PLA ; pull high byte + STA Itemph ; restore temporary integer high byte + RTS + +; convert float to fixed routine. accepts any value that fits in 24 bits, +ve or +; -ve and converts it into a right truncated integer in Itempl and Itemph + +; save unsigned 16 bit integer part of FAC1 in temporary integer + +LAB_F2FX + LDA FAC1_e ; get FAC1 exponent + CMP #$98 ; compare with exponent = 2^24 + BCS LAB_23A8 ; if >= do function call error then warm start + +LAB_F2FU + JSR LAB_2831 ; convert FAC1 floating-to-fixed + LDA FAC1_2 ; get FAC1 mantissa2 + LDY FAC1_3 ; get FAC1 mantissa3 + STY Itempl ; save temporary integer low byte + STA Itemph ; save temporary integer high byte + RTS + +; perform PEEK() + +LAB_PEEK + JSR LAB_F2FX ; save integer part of FAC1 in temporary integer + LDX #$00 ; clear index + LDA (Itempl,X) ; get byte via temporary integer (addr) + TAY ; copy byte to Y + JMP LAB_1FD0 ; convert Y to byte in FAC1 and return + +; perform POKE + +LAB_POKE + JSR LAB_GADB ; get two parameters for POKE or WAIT + TXA ; copy byte argument to A + LDX #$00 ; clear index + STA (Itempl,X) ; save byte via temporary integer (addr) + RTS + +; perform DEEK() + +LAB_DEEK + JSR LAB_F2FX ; save integer part of FAC1 in temporary integer + LDX #$00 ; clear index + LDA (Itempl,X) ; PEEK low byte + TAY ; copy to Y + INC Itempl ; increment pointer low byte + BNE Deekh ; skip high increment if no rollover + + INC Itemph ; increment pointer high byte +Deekh + LDA (Itempl,X) ; PEEK high byte + JMP LAB_AYFC ; save and convert integer AY to FAC1 and return + +; perform DOKE + +LAB_DOKE + JSR LAB_EVNM ; evaluate expression and check is numeric, + ; else do type mismatch + JSR LAB_F2FX ; convert floating-to-fixed + + STY Frnxtl ; save pointer low byte (float to fixed returns word in AY) + STA Frnxth ; save pointer high byte + + JSR LAB_1C01 ; scan for "," , else do syntax error then warm start + JSR LAB_EVNM ; evaluate expression and check is numeric, + ; else do type mismatch + JSR LAB_F2FX ; convert floating-to-fixed + + TYA ; copy value low byte (float to fixed returns word in AY) + LDX #$00 ; clear index + STA (Frnxtl,X) ; POKE low byte + INC Frnxtl ; increment pointer low byte + BNE Dokeh ; skip high increment if no rollover + + INC Frnxth ; increment pointer high byte +Dokeh + LDA Itemph ; get value high byte + STA (Frnxtl,X) ; POKE high byte + JMP LAB_GBYT ; scan memory and return + +; perform SWAP + +LAB_SWAP + JSR LAB_GVAR ; get var1 address + STA Lvarpl ; save var1 address low byte + STY Lvarph ; save var1 address high byte + LDA Dtypef ; get data type flag, $FF=string, $00=numeric + PHA ; save data type flag + + JSR LAB_1C01 ; scan for "," , else do syntax error then warm start + JSR LAB_GVAR ; get var2 address (pointer in Cvaral/h) + PLA ; pull var1 data type flag + EOR Dtypef ; compare with var2 data type + BPL SwapErr ; exit if not both the same type + + LDY #$03 ; four bytes to swap (either value or descriptor+1) +SwapLp + LDA (Lvarpl),Y ; get byte from var1 + TAX ; save var1 byte + LDA (Cvaral),Y ; get byte from var2 + STA (Lvarpl),Y ; save byte to var1 + TXA ; restore var1 byte + STA (Cvaral),Y ; save byte to var2 + DEY ; decrement index + BPL SwapLp ; loop until done + + RTS + +SwapErr + JMP LAB_1ABC ; do "Type mismatch" error then warm start + +; perform CALL + +LAB_CALL + JSR LAB_EVNM ; evaluate expression and check is numeric, + ; else do type mismatch + JSR LAB_F2FX ; convert floating-to-fixed + LDA #>CallExit ; set return address high byte + PHA ; put on stack + LDA #8 shifts) + BCC LAB_24A8 ;.go subtract mantissas + +; add 0.5 to FAC1 + +LAB_244E + LDA #LAB_2A96 ; set 0.5 pointer high byte + +; add (AY) to FAC1 + +LAB_246C + JSR LAB_264D ; unpack memory (AY) into FAC2 + +; add FAC2 to FAC1 + +LAB_ADD + BNE LAB_2474 ; branch if FAC1 was not zero + +; copy FAC2 to FAC1 + +LAB_279B + LDA FAC2_s ; get FAC2 sign (b7) + +; save FAC1 sign and copy ABS(FAC2) to FAC1 + +LAB_279D + STA FAC1_s ; save FAC1 sign (b7) + LDX #$04 ; 4 bytes to copy +LAB_27A1 + LDA FAC1_o,X ; get byte from FAC2,X + STA FAC1_e-1,X ; save byte at FAC1,X + DEX ; decrement count + BNE LAB_27A1 ; loop if not all done + + STX FAC1_r ; clear FAC1 rounding byte + RTS + + ; FAC1 is non zero +LAB_2474 + LDX FAC1_r ; get FAC1 rounding byte + STX FAC2_r ; save as FAC2 rounding byte + LDX #FAC2_e ; set index to FAC2 exponent addr + LDA FAC2_e ; get FAC2 exponent +LAB_247C + TAY ; copy exponent + BEQ LAB_244D ; exit if zero + + SEC ; set carry for subtract + SBC FAC1_e ; subtract FAC1 exponent + BEQ LAB_24A8 ; branch if = (go add mantissa) + + BCC LAB_2498 ; branch if < + + ; FAC2>FAC1 + STY FAC1_e ; save FAC1 exponent + LDY FAC2_s ; get FAC2 sign (b7) + STY FAC1_s ; save FAC1 sign (b7) + EOR #$FF ; complement A + ADC #$00 ; +1 (twos complement, carry is set) + LDY #$00 ; clear Y + STY FAC2_r ; clear FAC2 rounding byte + LDX #FAC1_e ; set index to FAC1 exponent addr + BNE LAB_249C ; branch always + +LAB_2498 + LDY #$00 ; clear Y + STY FAC1_r ; clear FAC1 rounding byte +LAB_249C + CMP #$F9 ; compare exponent diff with $F9 + BMI LAB_2467 ; branch if range $79-$F8 + + TAY ; copy exponent difference to Y + LDA FAC1_r ; get FAC1 rounding byte + LSR PLUS_1,X ; shift FAC? mantissa1 + JSR LAB_2592 ; shift FACX Y times right + + ; exponents are equal now do mantissa subtract +LAB_24A8 + BIT FAC_sc ; test sign compare (FAC1 EOR FAC2) + BPL LAB_24F8 ; if = add FAC2 mantissa to FAC1 mantissa and return + + LDY #FAC1_e ; set index to FAC1 exponent addr + CPX #FAC2_e ; compare X to FAC2 exponent addr + BEQ LAB_24B4 ; branch if = + + LDY #FAC2_e ; else set index to FAC2 exponent addr + + ; subtract smaller from bigger (take sign of bigger) +LAB_24B4 + SEC ; set carry for subtract + EOR #$FF ; ones complement A + ADC FAC2_r ; add FAC2 rounding byte + STA FAC1_r ; save FAC1 rounding byte + LDA PLUS_3,Y ; get FACY mantissa3 + SBC PLUS_3,X ; subtract FACX mantissa3 + STA FAC1_3 ; save FAC1 mantissa3 + LDA PLUS_2,Y ; get FACY mantissa2 + SBC PLUS_2,X ; subtract FACX mantissa2 + STA FAC1_2 ; save FAC1 mantissa2 + LDA PLUS_1,Y ; get FACY mantissa1 + SBC PLUS_1,X ; subtract FACX mantissa1 + STA FAC1_1 ; save FAC1 mantissa1 + +; do ABS and normalise FAC1 + +LAB_24D0 + BCS LAB_24D5 ; branch if number is +ve + + JSR LAB_2537 ; negate FAC1 + +; normalise FAC1 + +LAB_24D5 + LDY #$00 ; clear Y + TYA ; clear A + CLC ; clear carry for add +LAB_24D9 + LDX FAC1_1 ; get FAC1 mantissa1 + BNE LAB_251B ; if not zero normalise FAC1 + + LDX FAC1_2 ; get FAC1 mantissa2 + STX FAC1_1 ; save FAC1 mantissa1 + LDX FAC1_3 ; get FAC1 mantissa3 + STX FAC1_2 ; save FAC1 mantissa2 + LDX FAC1_r ; get FAC1 rounding byte + STX FAC1_3 ; save FAC1 mantissa3 + STY FAC1_r ; clear FAC1 rounding byte + ADC #$08 ; add x to exponent offset + CMP #$18 ; compare with $18 (max offset, all bits would be =0) + BNE LAB_24D9 ; loop if not max + +; clear FAC1 exponent and sign + +LAB_24F1 + LDA #$00 ; clear A +LAB_24F3 + STA FAC1_e ; set FAC1 exponent + +; save FAC1 sign + +LAB_24F5 + STA FAC1_s ; save FAC1 sign (b7) + RTS + +; add FAC2 mantissa to FAC1 mantissa + +LAB_24F8 + ADC FAC2_r ; add FAC2 rounding byte + STA FAC1_r ; save FAC1 rounding byte + LDA FAC1_3 ; get FAC1 mantissa3 + ADC FAC2_3 ; add FAC2 mantissa3 + STA FAC1_3 ; save FAC1 mantissa3 + LDA FAC1_2 ; get FAC1 mantissa2 + ADC FAC2_2 ; add FAC2 mantissa2 + STA FAC1_2 ; save FAC1 mantissa2 + LDA FAC1_1 ; get FAC1 mantissa1 + ADC FAC2_1 ; add FAC2 mantissa1 + STA FAC1_1 ; save FAC1 mantissa1 + BCS LAB_252A ; if carry then normalise FAC1 for C=1 + + RTS ; else just exit + +LAB_2511 + ADC #$01 ; add 1 to exponent offset + ASL FAC1_r ; shift FAC1 rounding byte + ROL FAC1_3 ; shift FAC1 mantissa3 + ROL FAC1_2 ; shift FAC1 mantissa2 + ROL FAC1_1 ; shift FAC1 mantissa1 + +; normalise FAC1 + +LAB_251B + BPL LAB_2511 ; loop if not normalised + + SEC ; set carry for subtract + SBC FAC1_e ; subtract FAC1 exponent + BCS LAB_24F1 ; branch if underflow (set result = $0) + + EOR #$FF ; complement exponent + ADC #$01 ; +1 (twos complement) + STA FAC1_e ; save FAC1 exponent + +; test and normalise FAC1 for C=0/1 + +LAB_2528 + BCC LAB_2536 ; exit if no overflow + +; normalise FAC1 for C=1 + +LAB_252A + INC FAC1_e ; increment FAC1 exponent + BEQ LAB_2564 ; if zero do overflow error and warm start + + ROR FAC1_1 ; shift FAC1 mantissa1 + ROR FAC1_2 ; shift FAC1 mantissa2 + ROR FAC1_3 ; shift FAC1 mantissa3 + ROR FAC1_r ; shift FAC1 rounding byte +LAB_2536 + RTS + +; negate FAC1 + +LAB_2537 + LDA FAC1_s ; get FAC1 sign (b7) + EOR #$FF ; complement it + STA FAC1_s ; save FAC1 sign (b7) + +; twos complement FAC1 mantissa + +LAB_253D + LDA FAC1_1 ; get FAC1 mantissa1 + EOR #$FF ; complement it + STA FAC1_1 ; save FAC1 mantissa1 + LDA FAC1_2 ; get FAC1 mantissa2 + EOR #$FF ; complement it + STA FAC1_2 ; save FAC1 mantissa2 + LDA FAC1_3 ; get FAC1 mantissa3 + EOR #$FF ; complement it + STA FAC1_3 ; save FAC1 mantissa3 + LDA FAC1_r ; get FAC1 rounding byte + EOR #$FF ; complement it + STA FAC1_r ; save FAC1 rounding byte + INC FAC1_r ; increment FAC1 rounding byte + BNE LAB_2563 ; exit if no overflow + +; increment FAC1 mantissa + +LAB_2559 + INC FAC1_3 ; increment FAC1 mantissa3 + BNE LAB_2563 ; finished if no rollover + + INC FAC1_2 ; increment FAC1 mantissa2 + BNE LAB_2563 ; finished if no rollover + + INC FAC1_1 ; increment FAC1 mantissa1 +LAB_2563 + RTS + +; do overflow error (overflow exit) + +LAB_2564 + LDX #$0A ; error code $0A ("Overflow" error) + JMP LAB_XERR ; do error #X, then warm start + +; shift FCAtemp << A+8 times + +LAB_2569 + LDX #FACt_1-1 ; set offset to FACtemp +LAB_256B + LDY PLUS_3,X ; get FACX mantissa3 + STY FAC1_r ; save as FAC1 rounding byte + LDY PLUS_2,X ; get FACX mantissa2 + STY PLUS_3,X ; save FACX mantissa3 + LDY PLUS_1,X ; get FACX mantissa1 + STY PLUS_2,X ; save FACX mantissa2 + LDY FAC1_o ; get FAC1 overflow byte + STY PLUS_1,X ; save FACX mantissa1 + +; shift FACX -A times right (> 8 shifts) + +LAB_257B + ADC #$08 ; add 8 to shift count + BMI LAB_256B ; go do 8 shift if still -ve + + BEQ LAB_256B ; go do 8 shift if zero + + SBC #$08 ; else subtract 8 again + TAY ; save count to Y + LDA FAC1_r ; get FAC1 rounding byte + BCS LAB_259A ;. + +LAB_2588 + ASL PLUS_1,X ; shift FACX mantissa1 + BCC LAB_258E ; branch if +ve + + INC PLUS_1,X ; this sets b7 eventually +LAB_258E + ROR PLUS_1,X ; shift FACX mantissa1 (correct for ASL) + ROR PLUS_1,X ; shift FACX mantissa1 (put carry in b7) + +; shift FACX Y times right + +LAB_2592 + ROR PLUS_2,X ; shift FACX mantissa2 + ROR PLUS_3,X ; shift FACX mantissa3 + ROR ; shift FACX rounding byte + INY ; increment exponent diff + BNE LAB_2588 ; branch if range adjust not complete + +LAB_259A + CLC ; just clear it + RTS + +; perform LOG() + +LAB_LOG + JSR LAB_27CA ; test sign and zero + BEQ LAB_25C4 ; if zero do function call error then warm start + + BPL LAB_25C7 ; skip error if +ve + +LAB_25C4 + JMP LAB_FCER ; do function call error then warm start (-ve) + +LAB_25C7 + LDA FAC1_e ; get FAC1 exponent + SBC #$7F ; normalise it + PHA ; save it + LDA #$80 ; set exponent to zero + STA FAC1_e ; save FAC1 exponent + LDA #LAB_25AD ; set 1/root2 pointer high byte + JSR LAB_246C ; add (AY) to FAC1 (1/root2) + LDA #LAB_25B1 ; set root2 pointer high byte + JSR LAB_26CA ; convert AY and do (AY)/FAC1 (root2/(x+(1/root2))) + LDA #LAB_259C ; set 1 pointer high byte + JSR LAB_2455 ; subtract (AY) from FAC1 ((root2/(x+(1/root2)))-1) + LDA #LAB_25A0 ; set pointer high byte to counter + JSR LAB_2B6E ; ^2 then series evaluation + LDA #LAB_25B5 ; set -0.5 pointer high byte + JSR LAB_246C ; add (AY) to FAC1 + PLA ; restore FAC1 exponent + JSR LAB_2912 ; evaluate new ASCII digit + LDA #LAB_25B9 ; set LOG(2) pointer high byte + +; do convert AY, FCA1*(AY) + +LAB_25FB + JSR LAB_264D ; unpack memory (AY) into FAC2 +LAB_MULTIPLY + BEQ LAB_264C ; exit if zero + + JSR LAB_2673 ; test and adjust accumulators + LDA #$00 ; clear A + STA FACt_1 ; clear temp mantissa1 + STA FACt_2 ; clear temp mantissa2 + STA FACt_3 ; clear temp mantissa3 + LDA FAC1_r ; get FAC1 rounding byte + JSR LAB_2622 ; go do shift/add FAC2 + LDA FAC1_3 ; get FAC1 mantissa3 + JSR LAB_2622 ; go do shift/add FAC2 + LDA FAC1_2 ; get FAC1 mantissa2 + JSR LAB_2622 ; go do shift/add FAC2 + LDA FAC1_1 ; get FAC1 mantissa1 + JSR LAB_2627 ; go do shift/add FAC2 + JMP LAB_273C ; copy temp to FAC1, normalise and return + +LAB_2622 + BNE LAB_2627 ; branch if byte <> zero + + JMP LAB_2569 ; shift FCAtemp << A+8 times + + ; else do shift and add +LAB_2627 + LSR ; shift byte + ORA #$80 ; set top bit (mark for 8 times) +LAB_262A + TAY ; copy result + BCC LAB_2640 ; skip next if bit was zero + + CLC ; clear carry for add + LDA FACt_3 ; get temp mantissa3 + ADC FAC2_3 ; add FAC2 mantissa3 + STA FACt_3 ; save temp mantissa3 + LDA FACt_2 ; get temp mantissa2 + ADC FAC2_2 ; add FAC2 mantissa2 + STA FACt_2 ; save temp mantissa2 + LDA FACt_1 ; get temp mantissa1 + ADC FAC2_1 ; add FAC2 mantissa1 + STA FACt_1 ; save temp mantissa1 +LAB_2640 + ROR FACt_1 ; shift temp mantissa1 + ROR FACt_2 ; shift temp mantissa2 + ROR FACt_3 ; shift temp mantissa3 + ROR FAC1_r ; shift temp rounding byte + TYA ; get byte back + LSR ; shift byte + BNE LAB_262A ; loop if all bits not done + +LAB_264C + RTS + +; unpack memory (AY) into FAC2 + +LAB_264D + STA ut1_pl ; save pointer low byte + STY ut1_ph ; save pointer high byte + LDY #$03 ; 4 bytes to get (0-3) + LDA (ut1_pl),Y ; get mantissa3 + STA FAC2_3 ; save FAC2 mantissa3 + DEY ; decrement index + LDA (ut1_pl),Y ; get mantissa2 + STA FAC2_2 ; save FAC2 mantissa2 + DEY ; decrement index + LDA (ut1_pl),Y ; get mantissa1+sign + STA FAC2_s ; save FAC2 sign (b7) + EOR FAC1_s ; EOR with FAC1 sign (b7) + STA FAC_sc ; save sign compare (FAC1 EOR FAC2) + LDA FAC2_s ; recover FAC2 sign (b7) + ORA #$80 ; set 1xxx xxx (set normal bit) + STA FAC2_1 ; save FAC2 mantissa1 + DEY ; decrement index + LDA (ut1_pl),Y ; get exponent byte + STA FAC2_e ; save FAC2 exponent + LDA FAC1_e ; get FAC1 exponent + RTS + +; test and adjust accumulators + +LAB_2673 + LDA FAC2_e ; get FAC2 exponent +LAB_2675 + BEQ LAB_2696 ; branch if FAC2 = $00 (handle underflow) + + CLC ; clear carry for add + ADC FAC1_e ; add FAC1 exponent + BCC LAB_2680 ; branch if sum of exponents <$0100 + + BMI LAB_269B ; do overflow error + + CLC ; clear carry for the add + .byte $2C ; makes next line BIT $1410 +LAB_2680 + BPL LAB_2696 ; if +ve go handle underflow + + ADC #$80 ; adjust exponent + STA FAC1_e ; save FAC1 exponent + BNE LAB_268B ; branch if not zero + + JMP LAB_24F5 ; save FAC1 sign and return + +LAB_268B + LDA FAC_sc ; get sign compare (FAC1 EOR FAC2) + STA FAC1_s ; save FAC1 sign (b7) +LAB_268F + RTS + +; handle overflow and underflow + +LAB_2690 + LDA FAC1_s ; get FAC1 sign (b7) + BPL LAB_269B ; do overflow error + + ; handle underflow +LAB_2696 + PLA ; pop return address low byte + PLA ; pop return address high byte + JMP LAB_24F1 ; clear FAC1 exponent and sign and return + +; multiply by 10 + +LAB_269E + JSR LAB_27AB ; round and copy FAC1 to FAC2 + TAX ; copy exponent (set the flags) + BEQ LAB_268F ; exit if zero + + CLC ; clear carry for add + ADC #$02 ; add two to exponent (*4) + BCS LAB_269B ; do overflow error if > $FF + + LDX #$00 ; clear byte + STX FAC_sc ; clear sign compare (FAC1 EOR FAC2) + JSR LAB_247C ; add FAC2 to FAC1 (*5) + INC FAC1_e ; increment FAC1 exponent (*10) + BNE LAB_268F ; if non zero just do RTS + +LAB_269B + JMP LAB_2564 ; do overflow error and warm start + +; divide by 10 + +LAB_26B9 + JSR LAB_27AB ; round and copy FAC1 to FAC2 + LDA #LAB_26B5 ; set pointer to 10d high addr + LDX #$00 ; clear sign + +; divide by (AY) (X=sign) + +LAB_26C2 + STX FAC_sc ; save sign compare (FAC1 EOR FAC2) + JSR LAB_UFAC ; unpack memory (AY) into FAC1 + JMP LAB_DIVIDE ; do FAC2/FAC1 + + ; Perform divide-by +; convert AY and do (AY)/FAC1 + +LAB_26CA + JSR LAB_264D ; unpack memory (AY) into FAC2 + + ; Perform divide-into +LAB_DIVIDE + BEQ LAB_2737 ; if zero go do /0 error + + JSR LAB_27BA ; round FAC1 + LDA #$00 ; clear A + SEC ; set carry for subtract + SBC FAC1_e ; subtract FAC1 exponent (2s complement) + STA FAC1_e ; save FAC1 exponent + JSR LAB_2673 ; test and adjust accumulators + INC FAC1_e ; increment FAC1 exponent + BEQ LAB_269B ; if zero do overflow error + + LDX #$FF ; set index for pre increment + LDA #$01 ; set bit to flag byte save +LAB_26E4 + LDY FAC2_1 ; get FAC2 mantissa1 + CPY FAC1_1 ; compare FAC1 mantissa1 + BNE LAB_26F4 ; branch if <> + + LDY FAC2_2 ; get FAC2 mantissa2 + CPY FAC1_2 ; compare FAC1 mantissa2 + BNE LAB_26F4 ; branch if <> + + LDY FAC2_3 ; get FAC2 mantissa3 + CPY FAC1_3 ; compare FAC1 mantissa3 +LAB_26F4 + PHP ; save FAC2-FAC1 compare status + ROL ; shift the result byte + BCC LAB_2702 ; if no carry skip the byte save + + LDY #$01 ; set bit to flag byte save + INX ; else increment the index to FACt + CPX #$02 ; compare with the index to FACt_3 + BMI LAB_2701 ; if not last byte just go save it + + BNE LAB_272B ; if all done go save FAC1 rounding byte, normalise and + ; return + + LDY #$40 ; set bit to flag byte save for the rounding byte +LAB_2701 + STA FACt_1,X ; write result byte to FACt_1 + index + TYA ; copy the next save byte flag +LAB_2702 + PLP ; restore FAC2-FAC1 compare status + BCC LAB_2704 ; if FAC2 < FAC1 then skip the subtract + + TAY ; save FAC2-FAC1 compare status + LDA FAC2_3 ; get FAC2 mantissa3 + SBC FAC1_3 ; subtract FAC1 mantissa3 + STA FAC2_3 ; save FAC2 mantissa3 + LDA FAC2_2 ; get FAC2 mantissa2 + SBC FAC1_2 ; subtract FAC1 mantissa2 + STA FAC2_2 ; save FAC2 mantissa2 + LDA FAC2_1 ; get FAC2 mantissa1 + SBC FAC1_1 ; subtract FAC1 mantissa1 + STA FAC2_1 ; save FAC2 mantissa1 + TYA ; restore FAC2-FAC1 compare status + + ; FAC2 = FAC2*2 +LAB_2704 + ASL FAC2_3 ; shift FAC2 mantissa3 + ROL FAC2_2 ; shift FAC2 mantissa2 + ROL FAC2_1 ; shift FAC2 mantissa1 + BCS LAB_26F4 ; loop with no compare + + BMI LAB_26E4 ; loop with compare + + BPL LAB_26F4 ; loop always with no compare + +; do A<<6, save as FAC1 rounding byte, normalise and return + +LAB_272B + LSR ; shift b1 - b0 .. + ROR ; .. + ROR ; .. to b7 - b6 + STA FAC1_r ; save FAC1 rounding byte + PLP ; dump FAC2-FAC1 compare status + JMP LAB_273C ; copy temp to FAC1, normalise and return + +; do "Divide by zero" error + +LAB_2737 + LDX #$14 ; error code $14 ("Divide by zero" error) + JMP LAB_XERR ; do error #X, then warm start + +; copy temp to FAC1 and normalise + +LAB_273C + LDA FACt_1 ; get temp mantissa1 + STA FAC1_1 ; save FAC1 mantissa1 + LDA FACt_2 ; get temp mantissa2 + STA FAC1_2 ; save FAC1 mantissa2 + LDA FACt_3 ; get temp mantissa3 + STA FAC1_3 ; save FAC1 mantissa3 + JMP LAB_24D5 ; normalise FAC1 and return + +; unpack memory (AY) into FAC1 + +LAB_UFAC + STA ut1_pl ; save pointer low byte + STY ut1_ph ; save pointer high byte + LDY #$03 ; 4 bytes to do + LDA (ut1_pl),Y ; get last byte + STA FAC1_3 ; save FAC1 mantissa3 + DEY ; decrement index + LDA (ut1_pl),Y ; get last-1 byte + STA FAC1_2 ; save FAC1 mantissa2 + DEY ; decrement index + LDA (ut1_pl),Y ; get second byte + STA FAC1_s ; save FAC1 sign (b7) + ORA #$80 ; set 1xxx xxxx (add normal bit) + STA FAC1_1 ; save FAC1 mantissa1 + DEY ; decrement index + LDA (ut1_pl),Y ; get first byte (exponent) + STA FAC1_e ; save FAC1 exponent + STY FAC1_r ; clear FAC1 rounding byte + RTS + +; pack FAC1 into Adatal + +LAB_276E + LDX #Adatal ; set pointer high byte + BEQ LAB_2778 ; pack FAC1 into (XY) and return + +; pack FAC1 into (Lvarpl) + +LAB_PFAC + LDX Lvarpl ; get destination pointer low byte + LDY Lvarph ; get destination pointer high byte + +; pack FAC1 into (XY) + +LAB_2778 + JSR LAB_27BA ; round FAC1 + STX ut1_pl ; save pointer low byte + STY ut1_ph ; save pointer high byte + LDY #$03 ; set index + LDA FAC1_3 ; get FAC1 mantissa3 + STA (ut1_pl),Y ; store in destination + DEY ; decrement index + LDA FAC1_2 ; get FAC1 mantissa2 + STA (ut1_pl),Y ; store in destination + DEY ; decrement index + LDA FAC1_s ; get FAC1 sign (b7) + ORA #$7F ; set bits x111 1111 + AND FAC1_1 ; AND in FAC1 mantissa1 + STA (ut1_pl),Y ; store in destination + DEY ; decrement index + LDA FAC1_e ; get FAC1 exponent + STA (ut1_pl),Y ; store in destination + STY FAC1_r ; clear FAC1 rounding byte + RTS + +; round and copy FAC1 to FAC2 + +LAB_27AB + JSR LAB_27BA ; round FAC1 + +; copy FAC1 to FAC2 + +LAB_27AE + LDX #$05 ; 5 bytes to copy +LAB_27B0 + LDA FAC1_e-1,X ; get byte from FAC1,X + STA FAC1_o,X ; save byte at FAC2,X + DEX ; decrement count + BNE LAB_27B0 ; loop if not all done + + STX FAC1_r ; clear FAC1 rounding byte +LAB_27B9 + RTS + +; round FAC1 + +LAB_27BA + LDA FAC1_e ; get FAC1 exponent + BEQ LAB_27B9 ; exit if zero + + ASL FAC1_r ; shift FAC1 rounding byte + BCC LAB_27B9 ; exit if no overflow + +; round FAC1 (no check) + +LAB_27C2 + JSR LAB_2559 ; increment FAC1 mantissa + BNE LAB_27B9 ; branch if no overflow + + JMP LAB_252A ; normalise FAC1 for C=1 and return + +; get FAC1 sign +; return A=FF,C=1/-ve A=01,C=0/+ve + +LAB_27CA + LDA FAC1_e ; get FAC1 exponent + BEQ LAB_27D7 ; exit if zero (already correct SGN(0)=0) + +; return A=FF,C=1/-ve A=01,C=0/+ve +; no = 0 check + +LAB_27CE + LDA FAC1_s ; else get FAC1 sign (b7) + +; return A=FF,C=1/-ve A=01,C=0/+ve +; no = 0 check, sign in A + +LAB_27D0 + ROL ; move sign bit to carry + LDA #$FF ; set byte for -ve result + BCS LAB_27D7 ; return if sign was set (-ve) + + LDA #$01 ; else set byte for +ve result +LAB_27D7 + RTS + +; perform SGN() + +LAB_SGN + JSR LAB_27CA ; get FAC1 sign + ; return A=$FF/-ve A=$01/+ve +; save A as integer byte + +LAB_27DB + STA FAC1_1 ; save FAC1 mantissa1 + LDA #$00 ; clear A + STA FAC1_2 ; clear FAC1 mantissa2 + LDX #$88 ; set exponent + +; set exp=X, clearFAC1 mantissa3 and normalise + +LAB_27E3 + LDA FAC1_1 ; get FAC1 mantissa1 + EOR #$FF ; complement it + ROL ; sign bit into carry + +; set exp=X, clearFAC1 mantissa3 and normalise + +LAB_STFA + LDA #$00 ; clear A + STA FAC1_3 ; clear FAC1 mantissa3 + STX FAC1_e ; set FAC1 exponent + STA FAC1_r ; clear FAC1 rounding byte + STA FAC1_s ; clear FAC1 sign (b7) + JMP LAB_24D0 ; do ABS and normalise FAC1 + +; perform ABS() + +LAB_ABS + LSR FAC1_s ; clear FAC1 sign (put zero in b7) + RTS + +; compare FAC1 with (AY) +; returns A=$00 if FAC1 = (AY) +; returns A=$01 if FAC1 > (AY) +; returns A=$FF if FAC1 < (AY) + +LAB_27F8 + STA ut2_pl ; save pointer low byte +LAB_27FA + STY ut2_ph ; save pointer high byte + LDY #$00 ; clear index + LDA (ut2_pl),Y ; get exponent + INY ; increment index + TAX ; copy (AY) exponent to X + BEQ LAB_27CA ; branch if (AY) exponent=0 and get FAC1 sign + ; A=FF,C=1/-ve A=01,C=0/+ve + + LDA (ut2_pl),Y ; get (AY) mantissa1 (with sign) + EOR FAC1_s ; EOR FAC1 sign (b7) + BMI LAB_27CE ; if signs <> do return A=FF,C=1/-ve + ; A=01,C=0/+ve and return + + CPX FAC1_e ; compare (AY) exponent with FAC1 exponent + BNE LAB_2828 ; branch if different + + LDA (ut2_pl),Y ; get (AY) mantissa1 (with sign) + ORA #$80 ; normalise top bit + CMP FAC1_1 ; compare with FAC1 mantissa1 + BNE LAB_2828 ; branch if different + + INY ; increment index + LDA (ut2_pl),Y ; get mantissa2 + CMP FAC1_2 ; compare with FAC1 mantissa2 + BNE LAB_2828 ; branch if different + + INY ; increment index + LDA #$7F ; set for 1/2 value rounding byte + CMP FAC1_r ; compare with FAC1 rounding byte (set carry) + LDA (ut2_pl),Y ; get mantissa3 + SBC FAC1_3 ; subtract FAC1 mantissa3 + BEQ LAB_2850 ; exit if mantissa3 equal + +; gets here if number <> FAC1 + +LAB_2828 + LDA FAC1_s ; get FAC1 sign (b7) + BCC LAB_282E ; branch if FAC1 > (AY) + + EOR #$FF ; else toggle FAC1 sign +LAB_282E + JMP LAB_27D0 ; return A=FF,C=1/-ve A=01,C=0/+ve + +; convert FAC1 floating-to-fixed + +LAB_2831 + LDA FAC1_e ; get FAC1 exponent + BEQ LAB_287F ; if zero go clear FAC1 and return + + SEC ; set carry for subtract + SBC #$98 ; subtract maximum integer range exponent + BIT FAC1_s ; test FAC1 sign (b7) + BPL LAB_2845 ; branch if FAC1 +ve + + ; FAC1 was -ve + TAX ; copy subtracted exponent + LDA #$FF ; overflow for -ve number + STA FAC1_o ; set FAC1 overflow byte + JSR LAB_253D ; twos complement FAC1 mantissa + TXA ; restore subtracted exponent +LAB_2845 + LDX #FAC1_e ; set index to FAC1 + CMP #$F9 ; compare exponent result + BPL LAB_2851 ; if < 8 shifts shift FAC1 A times right and return + + JSR LAB_257B ; shift FAC1 A times right (> 8 shifts) + STY FAC1_o ; clear FAC1 overflow byte +LAB_2850 + RTS + +; shift FAC1 A times right + +LAB_2851 + TAY ; copy shift count + LDA FAC1_s ; get FAC1 sign (b7) + AND #$80 ; mask sign bit only (x000 0000) + LSR FAC1_1 ; shift FAC1 mantissa1 + ORA FAC1_1 ; OR sign in b7 FAC1 mantissa1 + STA FAC1_1 ; save FAC1 mantissa1 + JSR LAB_2592 ; shift FAC1 Y times right + STY FAC1_o ; clear FAC1 overflow byte + RTS + +; perform INT() + +LAB_INT + LDA FAC1_e ; get FAC1 exponent + CMP #$98 ; compare with max int + BCS LAB_2886 ; exit if >= (already int, too big for fractional part!) + + JSR LAB_2831 ; convert FAC1 floating-to-fixed + STY FAC1_r ; save FAC1 rounding byte + LDA FAC1_s ; get FAC1 sign (b7) + STY FAC1_s ; save FAC1 sign (b7) + EOR #$80 ; toggle FAC1 sign + ROL ; shift into carry + LDA #$98 ; set new exponent + STA FAC1_e ; save FAC1 exponent + LDA FAC1_3 ; get FAC1 mantissa3 + STA Temp3 ; save for EXP() function + JMP LAB_24D0 ; do ABS and normalise FAC1 + +; clear FAC1 and return + +LAB_287F + STA FAC1_1 ; clear FAC1 mantissa1 + STA FAC1_2 ; clear FAC1 mantissa2 + STA FAC1_3 ; clear FAC1 mantissa3 + TAY ; clear Y +LAB_2886 + RTS + +; get FAC1 from string +; this routine now handles hex and binary values from strings +; starting with "$" and "%" respectively + +LAB_2887 + LDY #$00 ; clear Y + STY Dtypef ; clear data type flag, $FF=string, $00=numeric + LDX #$09 ; set index +LAB_288B + STY numexp,X ; clear byte + DEX ; decrement index + BPL LAB_288B ; loop until numexp to negnum (and FAC1) = $00 + + BCC LAB_28FE ; branch if 1st character numeric + +; get FAC1 from string .. first character wasn't numeric + + CMP #'-' ; else compare with "-" + BNE LAB_289A ; branch if not "-" + + STX negnum ; set flag for -ve number (X = $FF) + BEQ LAB_289C ; branch always (go scan and check for hex/bin) + +; get FAC1 from string .. first character wasn't numeric or - + +LAB_289A + CMP #'+' ; else compare with "+" + BNE LAB_289D ; branch if not "+" (go check for hex/bin) + +; was "+" or "-" to start, so get next character + +LAB_289C + JSR LAB_IGBY ; increment and scan memory + BCC LAB_28FE ; branch if numeric character + +; code here for hex and binary numbers + +LAB_289D + CMP #'$' ; else compare with "$" + BNE LAB_NHEX ; branch if not "$" + + JMP LAB_CHEX ; branch if "$" + +LAB_NHEX + CMP #'%' ; else compare with "%" + BNE LAB_28A3 ; branch if not "%" (continue original code) + + JMP LAB_CBIN ; branch if "%" + +LAB_289E + JSR LAB_IGBY ; increment and scan memory (ignore + or get next number) +LAB_28A1 + BCC LAB_28FE ; branch if numeric character + +; get FAC1 from string .. character wasn't numeric, -, +, hex or binary + +LAB_28A3 + CMP #'.' ; else compare with "." + BEQ LAB_28D5 ; branch if "." + +; get FAC1 from string .. character wasn't numeric, -, + or . + + CMP #'E' ; else compare with "E" + BNE LAB_28DB ; branch if not "E" + + ; was "E" so evaluate exponential part + JSR LAB_IGBY ; increment and scan memory + BCC LAB_28C7 ; branch if numeric character + + CMP #TK_MINUS ; else compare with token for - + BEQ LAB_28C2 ; branch if token for - + + CMP #'-' ; else compare with "-" + BEQ LAB_28C2 ; branch if "-" + + CMP #TK_PLUS ; else compare with token for + + BEQ LAB_28C4 ; branch if token for + + + CMP #'+' ; else compare with "+" + BEQ LAB_28C4 ; branch if "+" + + BNE LAB_28C9 ; branch always + +LAB_28C2 + ROR expneg ; set exponent -ve flag (C, which=1, into b7) +LAB_28C4 + JSR LAB_IGBY ; increment and scan memory +LAB_28C7 + BCC LAB_2925 ; branch if numeric character + +LAB_28C9 + BIT expneg ; test exponent -ve flag + BPL LAB_28DB ; if +ve go evaluate exponent + + ; else do exponent = -exponent + LDA #$00 ; clear result + SEC ; set carry for subtract + SBC expcnt ; subtract exponent byte + JMP LAB_28DD ; go evaluate exponent + +LAB_28D5 + ROR numdpf ; set decimal point flag + BIT numdpf ; test decimal point flag + BVC LAB_289E ; branch if only one decimal point so far + + ; evaluate exponent +LAB_28DB + LDA expcnt ; get exponent count byte +LAB_28DD + SEC ; set carry for subtract + SBC numexp ; subtract numerator exponent + STA expcnt ; save exponent count byte + BEQ LAB_28F6 ; branch if no adjustment + + BPL LAB_28EF ; else if +ve go do FAC1*10^expcnt + + ; else go do FAC1/10^(0-expcnt) +LAB_28E6 + JSR LAB_26B9 ; divide by 10 + INC expcnt ; increment exponent count byte + BNE LAB_28E6 ; loop until all done + + BEQ LAB_28F6 ; branch always + +LAB_28EF + JSR LAB_269E ; multiply by 10 + DEC expcnt ; decrement exponent count byte + BNE LAB_28EF ; loop until all done + +LAB_28F6 + LDA negnum ; get -ve flag + BMI LAB_28FB ; if -ve do - FAC1 and return + + RTS + +; do - FAC1 and return + +LAB_28FB + JMP LAB_GTHAN ; do - FAC1 and return + +; do unsigned FAC1*10+number + +LAB_28FE + PHA ; save character + BIT numdpf ; test decimal point flag + BPL LAB_2905 ; skip exponent increment if not set + + INC numexp ; else increment number exponent +LAB_2905 + JSR LAB_269E ; multiply FAC1 by 10 + PLA ; restore character + AND #$0F ; convert to binary + JSR LAB_2912 ; evaluate new ASCII digit + JMP LAB_289E ; go do next character + +; evaluate new ASCII digit + +LAB_2912 + PHA ; save digit + JSR LAB_27AB ; round and copy FAC1 to FAC2 + PLA ; restore digit + JSR LAB_27DB ; save A as integer byte + LDA FAC2_s ; get FAC2 sign (b7) + EOR FAC1_s ; toggle with FAC1 sign (b7) + STA FAC_sc ; save sign compare (FAC1 EOR FAC2) + LDX FAC1_e ; get FAC1 exponent + JMP LAB_ADD ; add FAC2 to FAC1 and return + +; evaluate next character of exponential part of number + +LAB_2925 + LDA expcnt ; get exponent count byte + CMP #$0A ; compare with 10 decimal + BCC LAB_2934 ; branch if less + + LDA #$64 ; make all -ve exponents = -100 decimal (causes underflow) + BIT expneg ; test exponent -ve flag + BMI LAB_2942 ; branch if -ve + + JMP LAB_2564 ; else do overflow error + +LAB_2934 + ASL ; * 2 + ASL ; * 4 + ADC expcnt ; * 5 + ASL ; * 10 + LDY #$00 ; set index + ADC (Bpntrl),Y ; add character (will be $30 too much!) + SBC #'0'-1 ; convert character to binary +LAB_2942 + STA expcnt ; save exponent count byte + JMP LAB_28C4 ; go get next character + +; print " in line [LINE #]" + +LAB_2953 + LDA #LAB_LMSG ; point to " in line " message high byte + JSR LAB_18C3 ; print null terminated string from memory + + ; print Basic line # + LDA Clineh ; get current line high byte + LDX Clinel ; get current line low byte + +; print XA as unsigned integer + +LAB_295E + STA FAC1_1 ; save low byte as FAC1 mantissa1 + STX FAC1_2 ; save high byte as FAC1 mantissa2 + LDX #$90 ; set exponent to 16d bits + SEC ; set integer is +ve flag + JSR LAB_STFA ; set exp=X, clearFAC1 mantissa3 and normalise + LDY #$00 ; clear index + TYA ; clear A + JSR LAB_297B ; convert FAC1 to string, skip sign character save + JMP LAB_18C3 ; print null terminated string from memory and return + +; convert FAC1 to ASCII string result in (AY) +; not any more, moved scratchpad to page 0 + +LAB_296E + LDY #$01 ; set index = 1 + LDA #$20 ; character = " " (assume +ve) + BIT FAC1_s ; test FAC1 sign (b7) + BPL LAB_2978 ; branch if +ve + + LDA #$2D ; else character = "-" +LAB_2978 + STA Decss,Y ; save leading character (" " or "-") +LAB_297B + STA FAC1_s ; clear FAC1 sign (b7) + STY Sendl ; save index + INY ; increment index + LDX FAC1_e ; get FAC1 exponent + BNE LAB_2989 ; branch if FAC1<>0 + + ; exponent was $00 so FAC1 is 0 + LDA #'0' ; set character = "0" + JMP LAB_2A89 ; save last character, [EOT] and exit + + ; FAC1 is some non zero value +LAB_2989 + LDA #$00 ; clear (number exponent count) + CPX #$81 ; compare FAC1 exponent with $81 (>1.00000) + + BCS LAB_299A ; branch if FAC1=>1 + + ; FAC1<1 + LDA #LAB_294F ; set pointer high byte to 1,000,000 + JSR LAB_25FB ; do convert AY, FCA1*(AY) + LDA #$FA ; set number exponent count (-6) +LAB_299A + STA numexp ; save number exponent count +LAB_299C + LDA #LAB_294B ; set pointer high byte to 999999.4375 + JSR LAB_27F8 ; compare FAC1 with (AY) + BEQ LAB_29C3 ; exit if FAC1 = (AY) + + BPL LAB_29B9 ; go do /10 if FAC1 > (AY) + + ; FAC1 < (AY) +LAB_29A7 + LDA #LAB_2947 ; set pointer high byte to 99999.9375 + JSR LAB_27F8 ; compare FAC1 with (AY) + BEQ LAB_29B2 ; branch if FAC1 = (AY) (allow decimal places) + + BPL LAB_29C0 ; branch if FAC1 > (AY) (no decimal places) + + ; FAC1 <= (AY) +LAB_29B2 + JSR LAB_269E ; multiply by 10 + DEC numexp ; decrement number exponent count + BNE LAB_29A7 ; go test again (branch always) + +LAB_29B9 + JSR LAB_26B9 ; divide by 10 + INC numexp ; increment number exponent count + BNE LAB_299C ; go test again (branch always) + +; now we have just the digits to do + +LAB_29C0 + JSR LAB_244E ; add 0.5 to FAC1 (round FAC1) +LAB_29C3 + JSR LAB_2831 ; convert FAC1 floating-to-fixed + LDX #$01 ; set default digits before dp = 1 + LDA numexp ; get number exponent count + CLC ; clear carry for add + ADC #$07 ; up to 6 digits before point + BMI LAB_29D8 ; if -ve then 1 digit before dp + + CMP #$08 ; A>=8 if n>=1E6 + BCS LAB_29D9 ; branch if >= $08 + + ; carry is clear + ADC #$FF ; take 1 from digit count + TAX ; copy to A + LDA #$02 ;.set exponent adjust +LAB_29D8 + SEC ; set carry for subtract +LAB_29D9 + SBC #$02 ; -2 + STA expcnt ;.save exponent adjust + STX numexp ; save digits before dp count + TXA ; copy to A + BEQ LAB_29E4 ; branch if no digits before dp + + BPL LAB_29F7 ; branch if digits before dp + +LAB_29E4 + LDY Sendl ; get output string index + LDA #$2E ; character "." + INY ; increment index + STA Decss,Y ; save to output string + TXA ;. + BEQ LAB_29F5 ;. + + LDA #'0' ; character "0" + INY ; increment index + STA Decss,Y ; save to output string +LAB_29F5 + STY Sendl ; save output string index +LAB_29F7 + LDY #$00 ; clear index (point to 100,000) + LDX #$80 ; +LAB_29FB + LDA FAC1_3 ; get FAC1 mantissa3 + CLC ; clear carry for add + ADC LAB_2A9C,Y ; add -ve LSB + STA FAC1_3 ; save FAC1 mantissa3 + LDA FAC1_2 ; get FAC1 mantissa2 + ADC LAB_2A9B,Y ; add -ve NMSB + STA FAC1_2 ; save FAC1 mantissa2 + LDA FAC1_1 ; get FAC1 mantissa1 + ADC LAB_2A9A,Y ; add -ve MSB + STA FAC1_1 ; save FAC1 mantissa1 + INX ; + BCS LAB_2A18 ; + + BPL LAB_29FB ; not -ve so try again + + BMI LAB_2A1A ; + +LAB_2A18 + BMI LAB_29FB ; + +LAB_2A1A + TXA ; + BCC LAB_2A21 ; + + EOR #$FF ; + ADC #$0A ; +LAB_2A21 + ADC #'0'-1 ; add "0"-1 to result + INY ; increment index .. + INY ; .. to next less .. + INY ; .. power of ten + STY Cvaral ; save as current var address low byte + LDY Sendl ; get output string index + INY ; increment output string index + TAX ; copy character to X + AND #$7F ; mask out top bit + STA Decss,Y ; save to output string + DEC numexp ; decrement # of characters before the dp + BNE LAB_2A3B ; branch if still characters to do + + ; else output the point + LDA #$2E ; character "." + INY ; increment output string index + STA Decss,Y ; save to output string +LAB_2A3B + STY Sendl ; save output string index + LDY Cvaral ; get current var address low byte + TXA ; get character back + EOR #$FF ; + AND #$80 ; + TAX ; + CPY #$12 ; compare index with max + BNE LAB_29FB ; loop if not max + + ; now remove trailing zeroes + LDY Sendl ; get output string index +LAB_2A4B + LDA Decss,Y ; get character from output string + DEY ; decrement output string index + CMP #'0' ; compare with "0" + BEQ LAB_2A4B ; loop until non "0" character found + + CMP #'.' ; compare with "." + BEQ LAB_2A58 ; branch if was dp + + ; restore last character + INY ; increment output string index +LAB_2A58 + LDA #$2B ; character "+" + LDX expcnt ; get exponent count + BEQ LAB_2A8C ; if zero go set null terminator and exit + + ; exponent isn't zero so write exponent + BPL LAB_2A68 ; branch if exponent count +ve + + LDA #$00 ; clear A + SEC ; set carry for subtract + SBC expcnt ; subtract exponent count adjust (convert -ve to +ve) + TAX ; copy exponent count to X + LDA #'-' ; character "-" +LAB_2A68 + STA Decss+2,Y ; save to output string + LDA #$45 ; character "E" + STA Decss+1,Y ; save exponent sign to output string + TXA ; get exponent count back + LDX #'0'-1 ; one less than "0" character + SEC ; set carry for subtract +LAB_2A74 + INX ; increment 10's character + SBC #$0A ;.subtract 10 from exponent count + BCS LAB_2A74 ; loop while still >= 0 + + ADC #':' ; add character ":" ($30+$0A, result is 10 less that value) + STA Decss+4,Y ; save to output string + TXA ; copy 10's character + STA Decss+3,Y ; save to output string + LDA #$00 ; set null terminator + STA Decss+5,Y ; save to output string + BEQ LAB_2A91 ; go set string pointer (AY) and exit (branch always) + + ; save last character, [EOT] and exit +LAB_2A89 + STA Decss,Y ; save last character to output string + + ; set null terminator and exit +LAB_2A8C + LDA #$00 ; set null terminator + STA Decss+1,Y ; save after last character + + ; set string pointer (AY) and exit +LAB_2A91 + LDA #Decssp1 ; set result string high pointer + RTS + +; perform power function + +LAB_POWER + BEQ LAB_EXP ; go do EXP() + + LDA FAC2_e ; get FAC2 exponent + BNE LAB_2ABF ; branch if FAC2<>0 + + JMP LAB_24F3 ; clear FAC1 exponent and sign and return + +LAB_2ABF + LDX #func_l ; set destination pointer high byte + JSR LAB_2778 ; pack FAC1 into (XY) + LDA FAC2_s ; get FAC2 sign (b7) + BPL LAB_2AD9 ; branch if FAC2>0 + + ; else FAC2 is -ve and can only be raised to an + ; integer power which gives an x +j0 result + JSR LAB_INT ; perform INT + LDA #func_l ; set source pointer high byte + JSR LAB_27F8 ; compare FAC1 with (AY) + BNE LAB_2AD9 ; branch if FAC1 <> (AY) to allow Function Call error + ; this will leave FAC1 -ve and cause a Function Call + ; error when LOG() is called + + TYA ; clear sign b7 + LDY Temp3 ; save mantissa 3 from INT() function as sign in Y + ; for possible later negation, b0 +LAB_2AD9 + JSR LAB_279D ; save FAC1 sign and copy ABS(FAC2) to FAC1 + TYA ; copy sign back .. + PHA ; .. and save it + JSR LAB_LOG ; do LOG(n) + LDA #garb_l ; set pointer high byte + JSR LAB_25FB ; do convert AY, FCA1*(AY) (square the value) + JSR LAB_EXP ; go do EXP(n) + PLA ; pull sign from stack + LSR ; b0 is to be tested, shift to Cb + BCC LAB_2AF9 ; if no bit then exit + + ; Perform negation +; do - FAC1 + +LAB_GTHAN + LDA FAC1_e ; get FAC1 exponent + BEQ LAB_2AF9 ; exit if FAC1_e = $00 + + LDA FAC1_s ; get FAC1 sign (b7) + EOR #$FF ; complement it + STA FAC1_s ; save FAC1 sign (b7) +LAB_2AF9 + RTS + +; perform EXP() (x^e) + +LAB_EXP + LDA #LAB_2AFA ; set 1.443 pointer high byte + JSR LAB_25FB ; do convert AY, FCA1*(AY) + LDA FAC1_r ; get FAC1 rounding byte + ADC #$50 ; +$50/$100 + BCC LAB_2B2B ; skip rounding if no carry + + JSR LAB_27C2 ; round FAC1 (no check) +LAB_2B2B + STA FAC2_r ; save FAC2 rounding byte + JSR LAB_27AE ; copy FAC1 to FAC2 + LDA FAC1_e ; get FAC1 exponent + CMP #$88 ; compare with EXP limit (256d) + BCC LAB_2B39 ; branch if less + +LAB_2B36 + JSR LAB_2690 ; handle overflow and underflow +LAB_2B39 + JSR LAB_INT ; perform INT + LDA Temp3 ; get mantissa 3 from INT() function + CLC ; clear carry for add + ADC #$81 ; normalise +1 + BEQ LAB_2B36 ; if $00 go handle overflow + + SEC ; set carry for subtract + SBC #$01 ; now correct for exponent + PHA ; save FAC2 exponent + + ; swap FAC1 and FAC2 + LDX #$04 ; 4 bytes to do +LAB_2B49 + LDA FAC2_e,X ; get FAC2,X + LDY FAC1_e,X ; get FAC1,X + STA FAC1_e,X ; save FAC1,X + STY FAC2_e,X ; save FAC2,X + DEX ; decrement count/index + BPL LAB_2B49 ; loop if not all done + + LDA FAC2_r ; get FAC2 rounding byte + STA FAC1_r ; save as FAC1 rounding byte + JSR LAB_SUBTRACT ; perform subtraction, FAC2 from FAC1 + JSR LAB_GTHAN ; do - FAC1 + LDA #LAB_2AFE ; set counter pointer high byte + JSR LAB_2B84 ; go do series evaluation + LDA #$00 ; clear A + STA FAC_sc ; clear sign compare (FAC1 EOR FAC2) + PLA ;.get saved FAC2 exponent + JMP LAB_2675 ; test and adjust accumulators and return + +; ^2 then series evaluation + +LAB_2B6E + STA Cptrl ; save count pointer low byte + STY Cptrh ; save count pointer high byte + JSR LAB_276E ; pack FAC1 into Adatal + LDA #Adatal ; pointer to original # high byte + JMP LAB_25FB ; do convert AY, FCA1*(AY) and return + +; series evaluation + +LAB_2B84 + STA Cptrl ; save count pointer low byte + STY Cptrh ; save count pointer high byte +LAB_2B88 + LDX #numexp ; set pointer high byte to partial @ numexp + DEC numcon ; decrement constants count + BNE LAB_2B9B ; loop until all done + + RTS + +; RND(n), 32 bit Galoise version. make n=0 for 19th next number in sequence or n<>0 +; to get 19th next number in sequence after seed n. This version of the PRNG uses +; the Galois method and a sample of 65536 bytes produced gives the following values. + +; Entropy = 7.997442 bits per byte +; Optimum compression would reduce these 65536 bytes by 0 percent + +; Chi square distribution for 65536 samples is 232.01, and +; randomly would exceed this value 75.00 percent of the time + +; Arithmetic mean value of data bytes is 127.6724, 127.5 would be random +; Monte Carlo value for Pi is 3.122871269, error 0.60 percent +; Serial correlation coefficient is -0.000370, totally uncorrelated would be 0.0 + +LAB_RND + LDA FAC1_e ; get FAC1 exponent + BEQ NextPRN ; do next random # if zero + + ; else get seed into random number store + LDX #Rbyte4 ; set PRNG pointer low byte + LDY #$00 ; set PRNG pointer high byte + JSR LAB_2778 ; pack FAC1 into (XY) +NextPRN + LDX #$AF ; set EOR byte + LDY #$13 ; do this nineteen times +LoopPRN + ASL Rbyte1 ; shift PRNG most significant byte + ROL Rbyte2 ; shift PRNG middle byte + ROL Rbyte3 ; shift PRNG least significant byte + ROL Rbyte4 ; shift PRNG extra byte + BCC Ninc1 ; branch if bit 32 clear + + TXA ; set EOR byte + EOR Rbyte1 ; EOR PRNG extra byte + STA Rbyte1 ; save new PRNG extra byte +Ninc1 + DEY ; decrement loop count + BNE LoopPRN ; loop if not all done + + LDX #$02 ; three bytes to copy +CopyPRNG + LDA Rbyte1,X ; get PRNG byte + STA FAC1_1,X ; save FAC1 byte + DEX + BPL CopyPRNG ; loop if not complete + + LDA #$80 ; set the exponent + STA FAC1_e ; save FAC1 exponent + + ASL ; clear A + STA FAC1_s ; save FAC1 sign + + JMP LAB_24D5 ; normalise FAC1 and return + +; perform COS() + +LAB_COS + LDA #LAB_2C78 ; set (pi/2) pointer high byte + JSR LAB_246C ; add (AY) to FAC1 + +; perform SIN() + +LAB_SIN + JSR LAB_27AB ; round and copy FAC1 to FAC2 + LDA #LAB_2C7C ; set (2*pi) pointer high byte + LDX FAC2_s ; get FAC2 sign (b7) + JSR LAB_26C2 ; divide by (AY) (X=sign) + JSR LAB_27AB ; round and copy FAC1 to FAC2 + JSR LAB_INT ; perform INT + LDA #$00 ; clear byte + STA FAC_sc ; clear sign compare (FAC1 EOR FAC2) + JSR LAB_SUBTRACT ; perform subtraction, FAC2 from FAC1 + LDA #LAB_2C80 ; set 0.25 pointer high byte + JSR LAB_2455 ; perform subtraction, (AY) from FAC1 + LDA FAC1_s ; get FAC1 sign (b7) + PHA ; save FAC1 sign + BPL LAB_2C35 ; branch if +ve + + ; FAC1 sign was -ve + JSR LAB_244E ; add 0.5 to FAC1 + LDA FAC1_s ; get FAC1 sign (b7) + BMI LAB_2C38 ; branch if -ve + + LDA Cflag ; get comparison evaluation flag + EOR #$FF ; toggle flag + STA Cflag ; save comparison evaluation flag +LAB_2C35 + JSR LAB_GTHAN ; do - FAC1 +LAB_2C38 + LDA #LAB_2C80 ; set 0.25 pointer high byte + JSR LAB_246C ; add (AY) to FAC1 + PLA ; restore FAC1 sign + BPL LAB_2C45 ; branch if was +ve + + ; else correct FAC1 + JSR LAB_GTHAN ; do - FAC1 +LAB_2C45 + LDA #LAB_2C84 ; set pointer high byte to counter + JMP LAB_2B6E ; ^2 then series evaluation and return + +; perform TAN() + +LAB_TAN + JSR LAB_276E ; pack FAC1 into Adatal + LDA #$00 ; clear byte + STA Cflag ; clear comparison evaluation flag + JSR LAB_SIN ; go do SIN(n) + LDX #func_l ; set sin(n) pointer high byte + JSR LAB_2778 ; pack FAC1 into (XY) + LDA #Adatal ; set n pointer high addr + JSR LAB_UFAC ; unpack memory (AY) into FAC1 + LDA #$00 ; clear byte + STA FAC1_s ; clear FAC1 sign (b7) + LDA Cflag ; get comparison evaluation flag + JSR LAB_2C74 ; save flag and go do series evaluation + + LDA #func_l ; set sin(n) pointer high byte + JMP LAB_26CA ; convert AY and do (AY)/FAC1 + +LAB_2C74 + PHA ; save comparison evaluation flag + JMP LAB_2C35 ; go do series evaluation + +; perform USR() + +LAB_USR + JSR Usrjmp ; call user code + JMP LAB_1BFB ; scan for ")", else do syntax error then warm start + +; perform ATN() + +LAB_ATN + LDA FAC1_s ; get FAC1 sign (b7) + PHA ; save sign + BPL LAB_2CA1 ; branch if +ve + + JSR LAB_GTHAN ; else do - FAC1 +LAB_2CA1 + LDA FAC1_e ; get FAC1 exponent + PHA ; push exponent + CMP #$81 ; compare with 1 + BCC LAB_2CAF ; branch if FAC1<1 + + LDA #LAB_259C ; set 1 pointer high byte + JSR LAB_26CA ; convert AY and do (AY)/FAC1 +LAB_2CAF + LDA #LAB_2CC9 ; set pointer high byte to counter + JSR LAB_2B6E ; ^2 then series evaluation + PLA ; restore old FAC1 exponent + CMP #$81 ; compare with 1 + BCC LAB_2CC2 ; branch if FAC1<1 + + LDA #LAB_2C78 ; set (pi/2) pointer high byte + JSR LAB_2455 ; perform subtraction, (AY) from FAC1 +LAB_2CC2 + PLA ; restore FAC1 sign + BPL LAB_2D04 ; exit if was +ve + + JMP LAB_GTHAN ; else do - FAC1 and return + +; perform BITSET + +LAB_BITSET + JSR LAB_GADB ; get two parameters for POKE or WAIT + CPX #$08 ; only 0 to 7 are allowed + BCS FCError ; branch if > 7 + + LDA #$00 ; clear A + SEC ; set the carry +S_Bits + ROL ; shift bit + DEX ; decrement bit number + BPL S_Bits ; loop if still +ve + + INX ; make X = $00 + ORA (Itempl,X) ; or with byte via temporary integer (addr) + STA (Itempl,X) ; save byte via temporary integer (addr) +LAB_2D04 + RTS + +; perform BITCLR + +LAB_BITCLR + JSR LAB_GADB ; get two parameters for POKE or WAIT + CPX #$08 ; only 0 to 7 are allowed + BCS FCError ; branch if > 7 + + LDA #$FF ; set A +S_Bitc + ROL ; shift bit + DEX ; decrement bit number + BPL S_Bitc ; loop if still +ve + + INX ; make X = $00 + AND (Itempl,X) ; and with byte via temporary integer (addr) + STA (Itempl,X) ; save byte via temporary integer (addr) + RTS + +FCError + JMP LAB_FCER ; do function call error then warm start + +; perform BITTST() + +LAB_BTST + JSR LAB_IGBY ; increment BASIC pointer + JSR LAB_GADB ; get two parameters for POKE or WAIT + CPX #$08 ; only 0 to 7 are allowed + BCS FCError ; branch if > 7 + + JSR LAB_GBYT ; get next BASIC byte + CMP #')' ; is next character ")" + BEQ TST_OK ; if ")" go do rest of function + + JMP LAB_SNER ; do syntax error then warm start + +TST_OK + JSR LAB_IGBY ; update BASIC execute pointer (to character past ")") + LDA #$00 ; clear A + SEC ; set the carry +T_Bits + ROL ; shift bit + DEX ; decrement bit number + BPL T_Bits ; loop if still +ve + + INX ; make X = $00 + AND (Itempl,X) ; AND with byte via temporary integer (addr) + BEQ LAB_NOTT ; branch if zero (already correct) + + LDA #$FF ; set for -1 result +LAB_NOTT + JMP LAB_27DB ; go do SGN tail + +; perform BIN$() + +LAB_BINS + CPX #$19 ; max + 1 + BCS BinFErr ; exit if too big ( > or = ) + + STX TempB ; save # of characters ($00 = leading zero remove) + LDA #$18 ; need A byte long space + JSR LAB_MSSP ; make string space A bytes long + LDY #$17 ; set index + LDX #$18 ; character count +NextB1 + LSR nums_1 ; shift highest byte + ROR nums_2 ; shift middle byte + ROR nums_3 ; shift lowest byte bit 0 to carry + TXA ; load with "0"/2 + ROL ; shift in carry + STA (str_pl),Y ; save to temp string + index + DEY ; decrement index + BPL NextB1 ; loop if not done + + LDA TempB ; get # of characters + BEQ EndBHS ; branch if truncate + + TAX ; copy length to X + SEC ; set carry for add ! + EOR #$FF ; 1's complement + ADC #$18 ; add 24d + BEQ GoPr2 ; if zero print whole string + + BNE GoPr1 ; else go make output string + +; this is the exit code and is also used by HEX$() +; truncate string to remove leading "0"s + +EndBHS + TAY ; clear index (A=0, X=length here) +NextB2 + LDA (str_pl),Y ; get character from string + CMP #'0' ; compare with "0" + BNE GoPr ; if not "0" then go print string from here + + DEX ; decrement character count + BEQ GoPr3 ; if zero then end of string so go print it + + INY ; else increment index + BPL NextB2 ; loop always + +; make fixed length output string - ignore overflows! + +GoPr3 + INX ; need at least 1 character +GoPr + TYA ; copy result +GoPr1 + CLC ; clear carry for add + ADC str_pl ; add low address + STA str_pl ; save low address + LDA #$00 ; do high byte + ADC str_ph ; add high address + STA str_ph ; save high address +GoPr2 + STX str_ln ; X holds string length + JSR LAB_IGBY ; update BASIC execute pointer (to character past ")") + JMP LAB_RTST ; check for space on descriptor stack then put address + ; and length on descriptor stack and update stack pointers + +BinFErr + JMP LAB_FCER ; do function call error then warm start + +; perform HEX$() + +LAB_HEXS + CPX #$07 ; max + 1 + BCS BinFErr ; exit if too big ( > or = ) + + STX TempB ; save # of characters + + LDA #$06 ; need 6 bytes for string + JSR LAB_MSSP ; make string space A bytes long + LDY #$05 ; set string index + + SED ; need decimal mode for nibble convert + LDA nums_3 ; get lowest byte + JSR LAB_A2HX ; convert A to ASCII hex byte and output + LDA nums_2 ; get middle byte + JSR LAB_A2HX ; convert A to ASCII hex byte and output + LDA nums_1 ; get highest byte + JSR LAB_A2HX ; convert A to ASCII hex byte and output + CLD ; back to binary + + LDX #$06 ; character count + LDA TempB ; get # of characters + BEQ EndBHS ; branch if truncate + + TAX ; copy length to X + SEC ; set carry for add ! + EOR #$FF ; 1's complement + ADC #$06 ; add 6d + BEQ GoPr2 ; if zero print whole string + + BNE GoPr1 ; else go make output string (branch always) + +; convert A to ASCII hex byte and output .. note set decimal mode before calling + +LAB_A2HX + TAX ; save byte + AND #$0F ; mask off top bits + JSR LAB_AL2X ; convert low nibble to ASCII and output + TXA ; get byte back + LSR ; /2 shift high nibble to low nibble + LSR ; /4 + LSR ; /8 + LSR ; /16 +LAB_AL2X + CMP #$0A ; set carry for +1 if >9 + ADC #'0' ; add ASCII "0" + STA (str_pl),Y ; save to temp string + DEY ; decrement counter + RTS + +LAB_NLTO + STA FAC1_e ; save FAC1 exponent + LDA #$00 ; clear sign compare +LAB_MLTE + STA FAC_sc ; save sign compare (FAC1 EOR FAC2) + TXA ; restore character + JSR LAB_2912 ; evaluate new ASCII digit + +; gets here if the first character was "$" for hex +; get hex number + +LAB_CHEX + JSR LAB_IGBY ; increment and scan memory + BCC LAB_ISHN ; branch if numeric character + + ORA #$20 ; case convert, allow "A" to "F" and "a" to "f" + SBC #'a' ; subtract "a" (carry set here) + CMP #$06 ; compare normalised with $06 (max+1) + BCS LAB_EXCH ; exit if >"f" or <"0" + + ADC #$0A ; convert to nibble +LAB_ISHN + AND #$0F ; convert to binary + TAX ; save nibble + LDA FAC1_e ; get FAC1 exponent + BEQ LAB_MLTE ; skip multiply if zero + + ADC #$04 ; add four to exponent (*16 - carry clear here) + BCC LAB_NLTO ; if no overflow do evaluate digit + +LAB_MLTO + JMP LAB_2564 ; do overflow error and warm start + +LAB_NXCH + TAX ; save bit + LDA FAC1_e ; get FAC1 exponent + BEQ LAB_MLBT ; skip multiply if zero + + INC FAC1_e ; increment FAC1 exponent (*2) + BEQ LAB_MLTO ; do overflow error if = $00 + + LDA #$00 ; clear sign compare +LAB_MLBT + STA FAC_sc ; save sign compare (FAC1 EOR FAC2) + TXA ; restore bit + JSR LAB_2912 ; evaluate new ASCII digit + +; gets here if the first character was "%" for binary +; get binary number + +LAB_CBIN + JSR LAB_IGBY ; increment and scan memory + EOR #'0' ; convert "0" to 0 etc. + CMP #$02 ; compare with max+1 + BCC LAB_NXCH ; branch exit if < 2 + +LAB_EXCH + JMP LAB_28F6 ; evaluate -ve flag and return + +; ctrl-c check routine. includes limited "life" byte save for INGET routine +; now also the code that checks to see if an interrupt has occurred + +CTRLC + LDA ccflag ; get [CTRL-C] check flag + BNE LAB_FBA2 ; exit if inhibited + + JSR V_INPT ; scan input device + BCC LAB_FBA0 ; exit if buffer empty + + STA ccbyte ; save received byte + LDX #$20 ; "life" timer for bytes + STX ccnull ; set countdown + JMP LAB_1636 ; return to BASIC + +LAB_FBA0 + LDX ccnull ; get countdown byte + BEQ LAB_FBA2 ; exit if finished + + DEC ccnull ; else decrement countdown +LAB_FBA2 + LDX #NmiBase ; set pointer to NMI values + JSR LAB_CKIN ; go check interrupt + LDX #IrqBase ; set pointer to IRQ values + JSR LAB_CKIN ; go check interrupt +LAB_CRTS + RTS + +; check whichever interrupt is indexed by X + +LAB_CKIN + LDA PLUS_0,X ; get interrupt flag byte + BPL LAB_CRTS ; branch if interrupt not enabled + +; we disable the interrupt here and make two new commands RETIRQ and RETNMI to +; automatically enable the interrupt when we exit + + ASL ; move happened bit to setup bit + AND #$40 ; mask happened bits + BEQ LAB_CRTS ; if no interrupt then exit + + STA PLUS_0,X ; save interrupt flag byte + + TXA ; copy index .. + TAY ; .. to Y + + PLA ; dump return address low byte, call from CTRL-C + PLA ; dump return address high byte + + LDA #$05 ; need 5 bytes for GOSUB + JSR LAB_1212 ; check room on stack for A bytes + LDA Bpntrh ; get BASIC execute pointer high byte + PHA ; push on stack + LDA Bpntrl ; get BASIC execute pointer low byte + PHA ; push on stack + LDA Clineh ; get current line high byte + PHA ; push on stack + LDA Clinel ; get current line low byte + PHA ; push on stack + LDA #TK_GOSUB ; token for GOSUB + PHA ; push on stack + + LDA PLUS_1,Y ; get interrupt code pointer low byte + STA Bpntrl ; save as BASIC execute pointer low byte + LDA PLUS_2,Y ; get interrupt code pointer high byte + STA Bpntrh ; save as BASIC execute pointer high byte + + JMP LAB_15C2 ; go do interpreter inner loop + ; can't RTS, we used the stack! the RTS from the ctrl-c + ; check will be taken when the RETIRQ/RETNMI/RETURN is + ; executed at the end of the subroutine + +; get byte from input device, no waiting +; returns with carry set if byte in A + +INGET + JSR V_INPT ; call scan input device + BCS LAB_FB95 ; if byte go reset timer + + LDA ccnull ; get countdown + BEQ LAB_FB96 ; exit if empty + + LDA ccbyte ; get last received byte + SEC ; flag we got a byte +LAB_FB95 + LDX #$00 ; clear X + STX ccnull ; clear timer because we got a byte +LAB_FB96 + RTS + +; these routines only enable the interrupts if the set-up flag is set +; if not they have no effect + +; perform IRQ {ON|OFF|CLEAR} + +LAB_IRQ + LDX #IrqBase ; set pointer to IRQ values + .byte $2C ; make next line BIT abs. + +; perform NMI {ON|OFF|CLEAR} + +LAB_NMI + LDX #NmiBase ; set pointer to NMI values + CMP #TK_ON ; compare with token for ON + BEQ LAB_INON ; go turn on interrupt + + CMP #TK_OFF ; compare with token for OFF + BEQ LAB_IOFF ; go turn off interrupt + + EOR #TK_CLEAR ; compare with token for CLEAR, A = $00 if = TK_CLEAR + BEQ LAB_INEX ; go clear interrupt flags and return + + JMP LAB_SNER ; do syntax error then warm start + +LAB_IOFF + LDA #$7F ; clear A + AND PLUS_0,X ; AND with interrupt setup flag + BPL LAB_INEX ; go clear interrupt enabled flag and return + +LAB_INON + LDA PLUS_0,X ; get interrupt setup flag + ASL ; Shift bit to enabled flag + ORA PLUS_0,X ; OR with flag byte +LAB_INEX + STA PLUS_0,X ; save interrupt flag byte + JMP LAB_IGBY ; update BASIC execute pointer and return + +; these routines set up the pointers and flags for the interrupt routines +; note that the interrupts are also enabled by these commands + +; perform ON IRQ + +LAB_SIRQ + CLI ; enable interrupts + LDX #IrqBase ; set pointer to IRQ values + .byte $2C ; make next line BIT abs. + +; perform ON NMI + +LAB_SNMI + LDX #NmiBase ; set pointer to NMI values + + STX TempB ; save interrupt pointer + JSR LAB_IGBY ; increment and scan memory (past token) + JSR LAB_GFPN ; get fixed-point number into temp integer + LDA Smeml ; get start of mem low byte + LDX Smemh ; get start of mem high byte + JSR LAB_SHLN ; search Basic for temp integer line number from AX + BCS LAB_LFND ; if carry set go set-up interrupt + + JMP LAB_16F7 ; else go do "Undefined statement" error and warm start + +LAB_LFND + LDX TempB ; get interrupt pointer + LDA Baslnl ; get pointer low byte + SBC #$01 ; -1 (carry already set for subtract) + STA PLUS_1,X ; save as interrupt pointer low byte + LDA Baslnh ; get pointer high byte + SBC #$00 ; subtract carry + STA PLUS_2,X ; save as interrupt pointer high byte + + LDA #$C0 ; set interrupt enabled/setup bits + STA PLUS_0,X ; set interrupt flags +LAB_IRTS + RTS + +; return from IRQ service, restores the enabled flag. + +; perform RETIRQ + +LAB_RETIRQ + BNE LAB_IRTS ; exit if following token (to allow syntax error) + + LDA IrqBase ; get interrupt flags + ASL ; copy setup to enabled (b7) + ORA IrqBase ; OR in setup flag + STA IrqBase ; save enabled flag + JMP LAB_16E8 ; go do rest of RETURN + +; return from NMI service, restores the enabled flag. + +; perform RETNMI + +LAB_RETNMI + BNE LAB_IRTS ; exit if following token (to allow syntax error) + + LDA NmiBase ; get set-up flag + ASL ; copy setup to enabled (b7) + ORA NmiBase ; OR in setup flag + STA NmiBase ; save enabled flag + JMP LAB_16E8 ; go do rest of RETURN + +; MAX() MIN() pre process + +LAB_MMPP + JSR LAB_EVEZ ; process expression + JMP LAB_CTNM ; check if source is numeric, else do type mismatch + +; perform MAX() + +LAB_MAX + JSR LAB_PHFA ; push FAC1, evaluate expression, + ; pull FAC2 and compare with FAC1 + BPL LAB_MAX ; branch if no swap to do + + LDA FAC2_1 ; get FAC2 mantissa1 + ORA #$80 ; set top bit (clear sign from compare) + STA FAC2_1 ; save FAC2 mantissa1 + JSR LAB_279B ; copy FAC2 to FAC1 + BEQ LAB_MAX ; go do next (branch always) + +; perform MIN() + +LAB_MIN + JSR LAB_PHFA ; push FAC1, evaluate expression, + ; pull FAC2 and compare with FAC1 + BMI LAB_MIN ; branch if no swap to do + + BEQ LAB_MIN ; branch if no swap to do + + LDA FAC2_1 ; get FAC2 mantissa1 + ORA #$80 ; set top bit (clear sign from compare) + STA FAC2_1 ; save FAC2 mantissa1 + JSR LAB_279B ; copy FAC2 to FAC1 + BEQ LAB_MIN ; go do next (branch always) + +; exit routine. don't bother returning to the loop code +; check for correct exit, else so syntax error + +LAB_MMEC + CMP #')' ; is it end of function? + BNE LAB_MMSE ; if not do MAX MIN syntax error + + PLA ; dump return address low byte + PLA ; dump return address high byte + JMP LAB_IGBY ; update BASIC execute pointer (to chr past ")") + +LAB_MMSE + JMP LAB_SNER ; do syntax error then warm start + +; check for next, evaluate and return or exit +; this is the routine that does most of the work + +LAB_PHFA + JSR LAB_GBYT ; get next BASIC byte + CMP #',' ; is there more ? + BNE LAB_MMEC ; if not go do end check + + ; push FAC1 + JSR LAB_27BA ; round FAC1 + LDA FAC1_s ; get FAC1 sign + ORA #$7F ; set all non sign bits + AND FAC1_1 ; AND FAC1 mantissa1 (AND in sign bit) + PHA ; push on stack + LDA FAC1_2 ; get FAC1 mantissa2 + PHA ; push on stack + LDA FAC1_3 ; get FAC1 mantissa3 + PHA ; push on stack + LDA FAC1_e ; get FAC1 exponent + PHA ; push on stack + + JSR LAB_IGBY ; scan and get next BASIC byte (after ",") + JSR LAB_EVNM ; evaluate expression and check is numeric, + ; else do type mismatch + + ; pop FAC2 (MAX/MIN expression so far) + PLA ; pop exponent + STA FAC2_e ; save FAC2 exponent + PLA ; pop mantissa3 + STA FAC2_3 ; save FAC2 mantissa3 + PLA ; pop mantissa1 + STA FAC2_2 ; save FAC2 mantissa2 + PLA ; pop sign/mantissa1 + STA FAC2_1 ; save FAC2 sign/mantissa1 + STA FAC2_s ; save FAC2 sign + + ; compare FAC1 with (packed) FAC2 + LDA #FAC2_e ; set pointer high byte to FAC2 + JMP LAB_27F8 ; compare FAC1 with FAC2 (AY) and return + ; returns A=$00 if FAC1 = (AY) + ; returns A=$01 if FAC1 > (AY) + ; returns A=$FF if FAC1 < (AY) + +; perform WIDTH + +LAB_WDTH + CMP #',' ; is next byte "," + BEQ LAB_TBSZ ; if so do tab size + + JSR LAB_GTBY ; get byte parameter + TXA ; copy width to A + BEQ LAB_NSTT ; branch if set for infinite line + + CPX #$10 ; else make min width = 16d + BCC TabErr ; if less do function call error and exit + +; this next compare ensures that we can't exit WIDTH via an error leaving the +; tab size greater than the line length. + + CPX TabSiz ; compare with tab size + BCS LAB_NSTT ; branch if >= tab size + + STX TabSiz ; else make tab size = terminal width +LAB_NSTT + STX TWidth ; set the terminal width + JSR LAB_GBYT ; get BASIC byte back + BEQ WExit ; exit if no following + + CMP #',' ; else is it "," + BNE LAB_MMSE ; if not do syntax error + +LAB_TBSZ + JSR LAB_SGBY ; scan and get byte parameter + TXA ; copy TAB size + BMI TabErr ; if >127 do function call error and exit + + CPX #$01 ; compare with min-1 + BCC TabErr ; if <=1 do function call error and exit + + LDA TWidth ; set flags for width + BEQ LAB_SVTB ; skip check if infinite line + + CPX TWidth ; compare TAB with width + BEQ LAB_SVTB ; ok if = + + BCS TabErr ; branch if too big + +LAB_SVTB + STX TabSiz ; save TAB size + +; calculate tab column limit from TAB size. The Iclim is set to the last tab +; position on a line that still has at least one whole tab width between it +; and the end of the line. + +WExit + LDA TWidth ; get width + BEQ LAB_SULP ; branch if infinite line + + CMP TabSiz ; compare with tab size + BCS LAB_WDLP ; branch if >= tab size + + STA TabSiz ; else make tab size = terminal width +LAB_SULP + SEC ; set carry for subtract +LAB_WDLP + SBC TabSiz ; subtract tab size + BCS LAB_WDLP ; loop while no borrow + + ADC TabSiz ; add tab size back + CLC ; clear carry for add + ADC TabSiz ; add tab size back again + STA Iclim ; save for now + LDA TWidth ; get width back + SEC ; set carry for subtract + SBC Iclim ; subtract remainder + STA Iclim ; save tab column limit +LAB_NOSQ + RTS + +TabErr + JMP LAB_FCER ; do function call error then warm start + +; perform SQR() + +LAB_SQR + LDA FAC1_s ; get FAC1 sign + BMI TabErr ; if -ve do function call error + + LDA FAC1_e ; get exponent + BEQ LAB_NOSQ ; if zero just return + + ; else do root + JSR LAB_27AB ; round and copy FAC1 to FAC2 + LDA #$00 ; clear A + + STA FACt_3 ; clear remainder + STA FACt_2 ; .. + STA FACt_1 ; .. + STA TempB ; .. + + STA FAC1_3 ; clear root + STA FAC1_2 ; .. + STA FAC1_1 ; .. + + LDX #$18 ; 24 pairs of bits to do + LDA FAC2_e ; get exponent + LSR ; check odd/even + BCS LAB_SQE2 ; if odd only 1 shift first time + +LAB_SQE1 + ASL FAC2_3 ; shift highest bit of number .. + ROL FAC2_2 ; .. + ROL FAC2_1 ; .. + ROL FACt_3 ; .. into remainder + ROL FACt_2 ; .. + ROL FACt_1 ; .. + ROL TempB ; .. never overflows +LAB_SQE2 + ASL FAC2_3 ; shift highest bit of number .. + ROL FAC2_2 ; .. + ROL FAC2_1 ; .. + ROL FACt_3 ; .. into remainder + ROL FACt_2 ; .. + ROL FACt_1 ; .. + ROL TempB ; .. never overflows + + ASL FAC1_3 ; root = root * 2 + ROL FAC1_2 ; .. + ROL FAC1_1 ; .. never overflows + + LDA FAC1_3 ; get root low byte + ROL ; *2 + STA Temp3 ; save partial low byte + LDA FAC1_2 ; get root low mid byte + ROL ; *2 + STA Temp3+1 ; save partial low mid byte + LDA FAC1_1 ; get root high mid byte + ROL ; *2 + STA Temp3+2 ; save partial high mid byte + LDA #$00 ; get root high byte (always $00) + ROL ; *2 + STA Temp3+3 ; save partial high byte + + ; carry clear for subtract +1 + LDA FACt_3 ; get remainder low byte + SBC Temp3 ; subtract partial low byte + STA Temp3 ; save partial low byte + + LDA FACt_2 ; get remainder low mid byte + SBC Temp3+1 ; subtract partial low mid byte + STA Temp3+1 ; save partial low mid byte + + LDA FACt_1 ; get remainder high mid byte + SBC Temp3+2 ; subtract partial high mid byte + TAY ; copy partial high mid byte + + LDA TempB ; get remainder high byte + SBC Temp3+3 ; subtract partial high byte + BCC LAB_SQNS ; skip sub if remainder smaller + + STA TempB ; save remainder high byte + + STY FACt_1 ; save remainder high mid byte + + LDA Temp3+1 ; get remainder low mid byte + STA FACt_2 ; save remainder low mid byte + + LDA Temp3 ; get partial low byte + STA FACt_3 ; save remainder low byte + + INC FAC1_3 ; increment root low byte (never any rollover) +LAB_SQNS + DEX ; decrement bit pair count + BNE LAB_SQE1 ; loop if not all done + + SEC ; set carry for subtract + LDA FAC2_e ; get exponent + SBC #$80 ; normalise + ROR ; /2 and re-bias to $80 + ADC #$00 ; add bit zero back in (allow for half shift) + STA FAC1_e ; save it + JMP LAB_24D5 ; normalise FAC1 and return + +; perform VARPTR() + +LAB_VARPTR + JSR LAB_IGBY ; increment and scan memory + JSR LAB_GVAR ; get var address + JSR LAB_1BFB ; scan for ")" , else do syntax error then warm start + LDY Cvaral ; get var address low byte + LDA Cvarah ; get var address high byte + JMP LAB_AYFC ; save and convert integer AY to FAC1 and return + +; perform PI + +LAB_PI + LDA #LAB_2C7C ; set (2*pi) pointer high byte + JSR LAB_UFAC ; unpack memory (AY) into FAC1 + DEC FAC1_e ; make result = PI + RTS + +; perform TWOPI + +LAB_TWOPI + LDA #LAB_2C7C ; set (2*pi) pointer high byte + JMP LAB_UFAC ; unpack memory (AY) into FAC1 and return + +; system dependant i/o vectors +; these are in RAM and are set by the monitor at start-up + +V_INPT + JMP (VEC_IN) ; non halting scan input device +V_OUTP + JMP (VEC_OUT) ; send byte to output device +V_LOAD + JMP (VEC_LD) ; load BASIC program +V_SAVE + JMP (VEC_SV) ; save BASIC program + +; The rest are tables messages and code for RAM + +; the rest of the code is tables and BASIC start-up code + +PG2_TABS + .byte $00 ; ctrl-c flag - $00 = enabled + .byte $00 ; ctrl-c byte - GET needs this + .byte $00 ; ctrl-c byte timeout - GET needs this + .word CTRLC ; ctrl c check vector +; .word xxxx ; non halting key input - monitor to set this +; .word xxxx ; output vector - monitor to set this +; .word xxxx ; load vector - monitor to set this +; .word xxxx ; save vector - monitor to set this +PG2_TABE + +; character get subroutine for zero page + +; For a 1.8432MHz 6502 including the JSR and RTS +; fastest (>=":") = 29 cycles = 15.7uS +; slowest (<":") = 40 cycles = 21.7uS +; space skip = +21 cycles = +11.4uS +; inc across page = +4 cycles = +2.2uS + +; the target address for the LDA at LAB_2CF4 becomes the BASIC execute pointer once the +; block is copied to it's destination, any non zero page address will do at assembly +; time, to assemble a three byte instruction. + +; page 0 initialisation table from $BC +; increment and scan memory + +LAB_2CEE + INC Bpntrl ; increment BASIC execute pointer low byte + BNE LAB_2CF4 ; branch if no carry + ; else + INC Bpntrh ; increment BASIC execute pointer high byte + +; page 0 initialisation table from $C2 +; scan memory + +LAB_2CF4 + LDA $FFFF ; get byte to scan (addr set by call routine) + CMP #TK_ELSE ; compare with the token for ELSE + BEQ LAB_2D05 ; exit if ELSE, not numeric, carry set + + CMP #':' ; compare with ":" + BCS LAB_2D05 ; exit if >= ":", not numeric, carry set + + CMP #' ' ; compare with " " + BEQ LAB_2CEE ; if " " go do next + + SEC ; set carry for SBC + SBC #'0' ; subtract "0" + SEC ; set carry for SBC + SBC #$D0 ; subtract -"0" + ; clear carry if byte = "0"-"9" +LAB_2D05 + RTS + +; page zero initialisation table $00-$12 inclusive + +StrTab + .byte $4C ; JMP opcode + .word LAB_COLD ; initial warm start vector (cold start) + + .byte $00 ; these bytes are not used by BASIC + .word $0000 ; + .word $0000 ; + .word $0000 ; + + .byte $4C ; JMP opcode + .word LAB_FCER ; initial user function vector ("Function call" error) + .byte $00 ; default NULL count + .byte $00 ; clear terminal position + .byte $00 ; default terminal width byte + .byte $F2 ; default limit for TAB = 14 + .word Ram_base ; start of user RAM +EndTab + +LAB_MSZM + .byte $0D,$0A,"Memory size ",$00 + +LAB_SMSG + .byte " Bytes free",$0D,$0A,$0A + .byte "Enhanced BASIC 2.22",$0A,$00 + +; numeric constants and series + + ; constants and series for LOG(n) +LAB_25A0 + .byte $02 ; counter + .byte $80,$19,$56,$62 ; 0.59898 + .byte $80,$76,$22,$F3 ; 0.96147 +;## .byte $80,$76,$22,$F1 ; 0.96147 + .byte $82,$38,$AA,$40 ; 2.88539 +;## .byte $82,$38,$AA,$45 ; 2.88539 + +LAB_25AD + .byte $80,$35,$04,$F3 ; 0.70711 1/root 2 +LAB_25B1 + .byte $81,$35,$04,$F3 ; 1.41421 root 2 +LAB_25B5 + .byte $80,$80,$00,$00 ; -0.5 +LAB_25B9 + .byte $80,$31,$72,$18 ; 0.69315 LOG(2) + + ; numeric PRINT constants +LAB_2947 + .byte $91,$43,$4F,$F8 ; 99999.9375 (max value with at least one decimal) +LAB_294B + .byte $94,$74,$23,$F7 ; 999999.4375 (max value before scientific notation) +LAB_294F + .byte $94,$74,$24,$00 ; 1000000 + + ; EXP(n) constants and series +LAB_2AFA + .byte $81,$38,$AA,$3B ; 1.4427 (1/LOG base 2 e) +LAB_2AFE + .byte $06 ; counter + .byte $74,$63,$90,$8C ; 2.17023e-4 + .byte $77,$23,$0C,$AB ; 0.00124 + .byte $7A,$1E,$94,$00 ; 0.00968 + .byte $7C,$63,$42,$80 ; 0.05548 + .byte $7E,$75,$FE,$D0 ; 0.24023 + .byte $80,$31,$72,$15 ; 0.69315 + .byte $81,$00,$00,$00 ; 1.00000 + +;## .byte $07 ; counter +;## .byte $74,$94,$2E,$40 ; -1/7! (-1/5040) +;## .byte $77,$2E,$4F,$70 ; 1/6! ( 1/720) +;## .byte $7A,$88,$02,$6E ; -1/5! (-1/120) +;## .byte $7C,$2A,$A0,$E6 ; 1/4! ( 1/24) +;## .byte $7E,$AA,$AA,$50 ; -1/3! (-1/6) +;## .byte $7F,$7F,$FF,$FF ; 1/2! ( 1/2) +;## .byte $81,$80,$00,$00 ; -1/1! (-1/1) +;## .byte $81,$00,$00,$00 ; 1/0! ( 1/1) + + ; trigonometric constants and series +LAB_2C78 + .byte $81,$49,$0F,$DB ; 1.570796371 (pi/2) as floating # +LAB_2C84 + .byte $04 ; counter + .byte $86,$1E,$D7,$FB ; 39.7109 +;## .byte $86,$1E,$D7,$BA ; 39.7109 + .byte $87,$99,$26,$65 ;-76.575 +;## .byte $87,$99,$26,$64 ;-76.575 + .byte $87,$23,$34,$58 ; 81.6022 + .byte $86,$A5,$5D,$E1 ;-41.3417 +;## .byte $86,$A5,$5D,$E0 ;-41.3417 +LAB_2C7C + .byte $83,$49,$0F,$DB ; 6.28319 (2*pi) as floating # +;## .byte $83,$49,$0F,$DA ; 6.28319 (2*pi) as floating # + +LAB_2CC9 + .byte $08 ; counter + .byte $78,$3A,$C5,$37 ; 0.00285 + .byte $7B,$83,$A2,$5C ;-0.0160686 + .byte $7C,$2E,$DD,$4D ; 0.0426915 + .byte $7D,$99,$B0,$1E ;-0.0750429 + .byte $7D,$59,$ED,$24 ; 0.106409 + .byte $7E,$91,$72,$00 ;-0.142036 + .byte $7E,$4C,$B9,$73 ; 0.199926 + .byte $7F,$AA,$AA,$53 ;-0.333331 + +;## .byte $08 ; counter +;## .byte $78,$3B,$D7,$4A ; 1/17 +;## .byte $7B,$84,$6E,$02 ;-1/15 +;## .byte $7C,$2F,$C1,$FE ; 1/13 +;## .byte $7D,$9A,$31,$74 ;-1/11 +;## .byte $7D,$5A,$3D,$84 ; 1/9 +;## .byte $7E,$91,$7F,$C8 ;-1/7 +;## .byte $7E,$4C,$BB,$E4 ; 1/5 +;## .byte $7F,$AA,$AA,$6C ;-1/3 + +LAB_1D96 = *+1 ; $00,$00 used for undefined variables +LAB_259C + .byte $81,$00,$00,$00 ; 1.000000, used for INC +LAB_2AFD + .byte $81,$80,$00,$00 ; -1.00000, used for DEC. must be on the same page as +1.00 + + ; misc constants +LAB_1DF7 + .byte $90 ;-32768 (uses first three bytes from 0.5) +LAB_2A96 + .byte $80,$00,$00,$00 ; 0.5 +LAB_2C80 + .byte $7F,$00,$00,$00 ; 0.25 +LAB_26B5 + .byte $84,$20,$00,$00 ; 10.0000 divide by 10 constant + +; This table is used in converting numbers to ASCII. + +LAB_2A9A +LAB_2A9B = LAB_2A9A+1 +LAB_2A9C = LAB_2A9B+1 + .byte $FE,$79,$60 ; -100000 + .byte $00,$27,$10 ; 10000 + .byte $FF,$FC,$18 ; -1000 + .byte $00,$00,$64 ; 100 + .byte $FF,$FF,$F6 ; -10 + .byte $00,$00,$01 ; 1 + +LAB_CTBL + .word LAB_END-1 ; END + .word LAB_FOR-1 ; FOR + .word LAB_NEXT-1 ; NEXT + .word LAB_DATA-1 ; DATA + .word LAB_INPUT-1 ; INPUT + .word LAB_DIM-1 ; DIM + .word LAB_READ-1 ; READ + .word LAB_LET-1 ; LET + .word LAB_DEC-1 ; DEC new command + .word LAB_GOTO-1 ; GOTO + .word LAB_RUN-1 ; RUN + .word LAB_IF-1 ; IF + .word LAB_RESTORE-1 ; RESTORE modified command + .word LAB_GOSUB-1 ; GOSUB + .word LAB_RETIRQ-1 ; RETIRQ new command + .word LAB_RETNMI-1 ; RETNMI new command + .word LAB_RETURN-1 ; RETURN + .word LAB_REM-1 ; REM + .word LAB_STOP-1 ; STOP + .word LAB_ON-1 ; ON modified command + .word LAB_NULL-1 ; NULL modified command + .word LAB_INC-1 ; INC new command + .word LAB_WAIT-1 ; WAIT + .word V_LOAD-1 ; LOAD + .word V_SAVE-1 ; SAVE + .word LAB_DEF-1 ; DEF + .word LAB_POKE-1 ; POKE + .word LAB_DOKE-1 ; DOKE new command + .word LAB_CALL-1 ; CALL new command + .word LAB_DO-1 ; DO new command + .word LAB_LOOP-1 ; LOOP new command + .word LAB_PRINT-1 ; PRINT + .word LAB_CONT-1 ; CONT + .word LAB_LIST-1 ; LIST + .word LAB_CLEAR-1 ; CLEAR + .word LAB_NEW-1 ; NEW + .word LAB_WDTH-1 ; WIDTH new command + .word LAB_GET-1 ; GET new command + .word LAB_SWAP-1 ; SWAP new command + .word LAB_BITSET-1 ; BITSET new command + .word LAB_BITCLR-1 ; BITCLR new command + .word LAB_IRQ-1 ; IRQ new command + .word LAB_NMI-1 ; NMI new command + +; function pre process routine table + +LAB_FTPL +LAB_FTPM = LAB_FTPL+$01 + .word LAB_PPFN-1 ; SGN(n) process numeric expression in () + .word LAB_PPFN-1 ; INT(n) " + .word LAB_PPFN-1 ; ABS(n) " + .word LAB_EVEZ-1 ; USR(x) process any expression + .word LAB_1BF7-1 ; FRE(x) " + .word LAB_1BF7-1 ; POS(x) " + .word LAB_PPFN-1 ; SQR(n) process numeric expression in () + .word LAB_PPFN-1 ; RND(n) " + .word LAB_PPFN-1 ; LOG(n) " + .word LAB_PPFN-1 ; EXP(n) " + .word LAB_PPFN-1 ; COS(n) " + .word LAB_PPFN-1 ; SIN(n) " + .word LAB_PPFN-1 ; TAN(n) " + .word LAB_PPFN-1 ; ATN(n) " + .word LAB_PPFN-1 ; PEEK(n) " + .word LAB_PPFN-1 ; DEEK(n) " + .word $0000 ; SADD() none + .word LAB_PPFS-1 ; LEN($) process string expression in () + .word LAB_PPFN-1 ; STR$(n) process numeric expression in () + .word LAB_PPFS-1 ; VAL($) process string expression in () + .word LAB_PPFS-1 ; ASC($) " + .word LAB_PPFS-1 ; UCASE$($) " + .word LAB_PPFS-1 ; LCASE$($) " + .word LAB_PPFN-1 ; CHR$(n) process numeric expression in () + .word LAB_BHSS-1 ; HEX$(n) " + .word LAB_BHSS-1 ; BIN$(n) " + .word $0000 ; BITTST() none + .word LAB_MMPP-1 ; MAX() process numeric expression + .word LAB_MMPP-1 ; MIN() " + .word LAB_PPBI-1 ; PI advance pointer + .word LAB_PPBI-1 ; TWOPI " + .word $0000 ; VARPTR() none + .word LAB_LRMS-1 ; LEFT$() process string expression + .word LAB_LRMS-1 ; RIGHT$() " + .word LAB_LRMS-1 ; MID$() " + +; action addresses for functions + +LAB_FTBL +LAB_FTBM = LAB_FTBL+$01 + .word LAB_SGN-1 ; SGN() + .word LAB_INT-1 ; INT() + .word LAB_ABS-1 ; ABS() + .word LAB_USR-1 ; USR() + .word LAB_FRE-1 ; FRE() + .word LAB_POS-1 ; POS() + .word LAB_SQR-1 ; SQR() + .word LAB_RND-1 ; RND() modified function + .word LAB_LOG-1 ; LOG() + .word LAB_EXP-1 ; EXP() + .word LAB_COS-1 ; COS() + .word LAB_SIN-1 ; SIN() + .word LAB_TAN-1 ; TAN() + .word LAB_ATN-1 ; ATN() + .word LAB_PEEK-1 ; PEEK() + .word LAB_DEEK-1 ; DEEK() new function + .word LAB_SADD-1 ; SADD() new function + .word LAB_LENS-1 ; LEN() + .word LAB_STRS-1 ; STR$() + .word LAB_VAL-1 ; VAL() + .word LAB_ASC-1 ; ASC() + .word LAB_UCASE-1 ; UCASE$() new function + .word LAB_LCASE-1 ; LCASE$() new function + .word LAB_CHRS-1 ; CHR$() + .word LAB_HEXS-1 ; HEX$() new function + .word LAB_BINS-1 ; BIN$() new function + .word LAB_BTST-1 ; BITTST() new function + .word LAB_MAX-1 ; MAX() new function + .word LAB_MIN-1 ; MIN() new function + .word LAB_PI-1 ; PI new function + .word LAB_TWOPI-1 ; TWOPI new function + .word LAB_VARPTR-1 ; VARPTR() new function + .word LAB_LEFT-1 ; LEFT$() + .word LAB_RIGHT-1 ; RIGHT$() + .word LAB_MIDS-1 ; MID$() + +; hierarchy and action addresses for operator + +LAB_OPPT + .byte $79 ; + + .word LAB_ADD-1 + .byte $79 ; - + .word LAB_SUBTRACT-1 + .byte $7B ; * + .word LAB_MULTIPLY-1 + .byte $7B ; / + .word LAB_DIVIDE-1 + .byte $7F ; ^ + .word LAB_POWER-1 + .byte $50 ; AND + .word LAB_AND-1 + .byte $46 ; EOR new operator + .word LAB_EOR-1 + .byte $46 ; OR + .word LAB_OR-1 + .byte $56 ; >> new operator + .word LAB_RSHIFT-1 + .byte $56 ; << new operator + .word LAB_LSHIFT-1 + .byte $7D ; > + .word LAB_GTHAN-1 + .byte $5A ; = + .word LAB_EQUAL-1 + .byte $64 ; < + .word LAB_LTHAN-1 + +; keywords start with .. +; this is the first character table and must be in alphabetic order + +TAB_1STC + .byte "*" + .byte "+" + .byte "-" + .byte "/" + .byte "<" + .byte "=" + .byte ">" + .byte "?" + .byte "A" + .byte "B" + .byte "C" + .byte "D" + .byte "E" + .byte "F" + .byte "G" + .byte "H" + .byte "I" + .byte "L" + .byte "M" + .byte "N" + .byte "O" + .byte "P" + .byte "R" + .byte "S" + .byte "T" + .byte "U" + .byte "V" + .byte "W" + .byte "^" + .byte $00 ; table terminator + +; pointers to keyword tables + +TAB_CHRT + .word TAB_STAR ; table for "*" + .word TAB_PLUS ; table for "+" + .word TAB_MNUS ; table for "-" + .word TAB_SLAS ; table for "/" + .word TAB_LESS ; table for "<" + .word TAB_EQUL ; table for "=" + .word TAB_MORE ; table for ">" + .word TAB_QEST ; table for "?" + .word TAB_ASCA ; table for "A" + .word TAB_ASCB ; table for "B" + .word TAB_ASCC ; table for "C" + .word TAB_ASCD ; table for "D" + .word TAB_ASCE ; table for "E" + .word TAB_ASCF ; table for "F" + .word TAB_ASCG ; table for "G" + .word TAB_ASCH ; table for "H" + .word TAB_ASCI ; table for "I" + .word TAB_ASCL ; table for "L" + .word TAB_ASCM ; table for "M" + .word TAB_ASCN ; table for "N" + .word TAB_ASCO ; table for "O" + .word TAB_ASCP ; table for "P" + .word TAB_ASCR ; table for "R" + .word TAB_ASCS ; table for "S" + .word TAB_ASCT ; table for "T" + .word TAB_ASCU ; table for "U" + .word TAB_ASCV ; table for "V" + .word TAB_ASCW ; table for "W" + .word TAB_POWR ; table for "^" + +; tables for each start character, note if a longer keyword with the same start +; letters as a shorter one exists then it must come first, else the list is in +; alphabetical order as follows .. + +; [keyword,token +; [keyword,token]] +; end marker (#$00) + +TAB_STAR + .byte TK_MUL,$00 ; * +TAB_PLUS + .byte TK_PLUS,$00 ; + +TAB_MNUS + .byte TK_MINUS,$00 ; - +TAB_SLAS + .byte TK_DIV,$00 ; / +TAB_LESS +LBB_LSHIFT + .byte "<",TK_LSHIFT ; << note - "<<" must come before "<" + .byte TK_LT ; < + .byte $00 +TAB_EQUL + .byte TK_EQUAL,$00 ; = +TAB_MORE +LBB_RSHIFT + .byte ">",TK_RSHIFT ; >> note - ">>" must come before ">" + .byte TK_GT ; > + .byte $00 +TAB_QEST + .byte TK_PRINT,$00 ; ? +TAB_ASCA +LBB_ABS + .byte "BS(",TK_ABS ; ABS( +LBB_AND + .byte "ND",TK_AND ; AND +LBB_ASC + .byte "SC(",TK_ASC ; ASC( +LBB_ATN + .byte "TN(",TK_ATN ; ATN( + .byte $00 +TAB_ASCB +LBB_BINS + .byte "IN$(",TK_BINS ; BIN$( +LBB_BITCLR + .byte "ITCLR",TK_BITCLR ; BITCLR +LBB_BITSET + .byte "ITSET",TK_BITSET ; BITSET +LBB_BITTST + .byte "ITTST(",TK_BITTST + ; BITTST( + .byte $00 +TAB_ASCC +LBB_CALL + .byte "ALL",TK_CALL ; CALL +LBB_CHRS + .byte "HR$(",TK_CHRS ; CHR$( +LBB_CLEAR + .byte "LEAR",TK_CLEAR ; CLEAR +LBB_CONT + .byte "ONT",TK_CONT ; CONT +LBB_COS + .byte "OS(",TK_COS ; COS( + .byte $00 +TAB_ASCD +LBB_DATA + .byte "ATA",TK_DATA ; DATA +LBB_DEC + .byte "EC",TK_DEC ; DEC +LBB_DEEK + .byte "EEK(",TK_DEEK ; DEEK( +LBB_DEF + .byte "EF",TK_DEF ; DEF +LBB_DIM + .byte "IM",TK_DIM ; DIM +LBB_DOKE + .byte "OKE",TK_DOKE ; DOKE note - "DOKE" must come before "DO" +LBB_DO + .byte "O",TK_DO ; DO + .byte $00 +TAB_ASCE +LBB_ELSE + .byte "LSE",TK_ELSE ; ELSE +LBB_END + .byte "ND",TK_END ; END +LBB_EOR + .byte "OR",TK_EOR ; EOR +LBB_EXP + .byte "XP(",TK_EXP ; EXP( + .byte $00 +TAB_ASCF +LBB_FN + .byte "N",TK_FN ; FN +LBB_FOR + .byte "OR",TK_FOR ; FOR +LBB_FRE + .byte "RE(",TK_FRE ; FRE( + .byte $00 +TAB_ASCG +LBB_GET + .byte "ET",TK_GET ; GET +LBB_GOSUB + .byte "OSUB",TK_GOSUB ; GOSUB +LBB_GOTO + .byte "OTO",TK_GOTO ; GOTO + .byte $00 +TAB_ASCH +LBB_HEXS + .byte "EX$(",TK_HEXS ; HEX$( + .byte $00 +TAB_ASCI +LBB_IF + .byte "F",TK_IF ; IF +LBB_INC + .byte "NC",TK_INC ; INC +LBB_INPUT + .byte "NPUT",TK_INPUT ; INPUT +LBB_INT + .byte "NT(",TK_INT ; INT( +LBB_IRQ + .byte "RQ",TK_IRQ ; IRQ + .byte $00 +TAB_ASCL +LBB_LCASES + .byte "CASE$(",TK_LCASES + ; LCASE$( +LBB_LEFTS + .byte "EFT$(",TK_LEFTS ; LEFT$( +LBB_LEN + .byte "EN(",TK_LEN ; LEN( +LBB_LET + .byte "ET",TK_LET ; LET +LBB_LIST + .byte "IST",TK_LIST ; LIST +LBB_LOAD + .byte "OAD",TK_LOAD ; LOAD +LBB_LOG + .byte "OG(",TK_LOG ; LOG( +LBB_LOOP + .byte "OOP",TK_LOOP ; LOOP + .byte $00 +TAB_ASCM +LBB_MAX + .byte "AX(",TK_MAX ; MAX( +LBB_MIDS + .byte "ID$(",TK_MIDS ; MID$( +LBB_MIN + .byte "IN(",TK_MIN ; MIN( + .byte $00 +TAB_ASCN +LBB_NEW + .byte "EW",TK_NEW ; NEW +LBB_NEXT + .byte "EXT",TK_NEXT ; NEXT +LBB_NMI + .byte "MI",TK_NMI ; NMI +LBB_NOT + .byte "OT",TK_NOT ; NOT +LBB_NULL + .byte "ULL",TK_NULL ; NULL + .byte $00 +TAB_ASCO +LBB_OFF + .byte "FF",TK_OFF ; OFF +LBB_ON + .byte "N",TK_ON ; ON +LBB_OR + .byte "R",TK_OR ; OR + .byte $00 +TAB_ASCP +LBB_PEEK + .byte "EEK(",TK_PEEK ; PEEK( +LBB_PI + .byte "I",TK_PI ; PI +LBB_POKE + .byte "OKE",TK_POKE ; POKE +LBB_POS + .byte "OS(",TK_POS ; POS( +LBB_PRINT + .byte "RINT",TK_PRINT ; PRINT + .byte $00 +TAB_ASCR +LBB_READ + .byte "EAD",TK_READ ; READ +LBB_REM + .byte "EM",TK_REM ; REM +LBB_RESTORE + .byte "ESTORE",TK_RESTORE + ; RESTORE +LBB_RETIRQ + .byte "ETIRQ",TK_RETIRQ ; RETIRQ +LBB_RETNMI + .byte "ETNMI",TK_RETNMI ; RETNMI +LBB_RETURN + .byte "ETURN",TK_RETURN ; RETURN +LBB_RIGHTS + .byte "IGHT$(",TK_RIGHTS + ; RIGHT$( +LBB_RND + .byte "ND(",TK_RND ; RND( +LBB_RUN + .byte "UN",TK_RUN ; RUN + .byte $00 +TAB_ASCS +LBB_SADD + .byte "ADD(",TK_SADD ; SADD( +LBB_SAVE + .byte "AVE",TK_SAVE ; SAVE +LBB_SGN + .byte "GN(",TK_SGN ; SGN( +LBB_SIN + .byte "IN(",TK_SIN ; SIN( +LBB_SPC + .byte "PC(",TK_SPC ; SPC( +LBB_SQR + .byte "QR(",TK_SQR ; SQR( +LBB_STEP + .byte "TEP",TK_STEP ; STEP +LBB_STOP + .byte "TOP",TK_STOP ; STOP +LBB_STRS + .byte "TR$(",TK_STRS ; STR$( +LBB_SWAP + .byte "WAP",TK_SWAP ; SWAP + .byte $00 +TAB_ASCT +LBB_TAB + .byte "AB(",TK_TAB ; TAB( +LBB_TAN + .byte "AN(",TK_TAN ; TAN( +LBB_THEN + .byte "HEN",TK_THEN ; THEN +LBB_TO + .byte "O",TK_TO ; TO +LBB_TWOPI + .byte "WOPI",TK_TWOPI ; TWOPI + .byte $00 +TAB_ASCU +LBB_UCASES + .byte "CASE$(",TK_UCASES + ; UCASE$( +LBB_UNTIL + .byte "NTIL",TK_UNTIL ; UNTIL +LBB_USR + .byte "SR(",TK_USR ; USR( + .byte $00 +TAB_ASCV +LBB_VAL + .byte "AL(",TK_VAL ; VAL( +LBB_VPTR + .byte "ARPTR(",TK_VPTR ; VARPTR( + .byte $00 +TAB_ASCW +LBB_WAIT + .byte "AIT",TK_WAIT ; WAIT +LBB_WHILE + .byte "HILE",TK_WHILE ; WHILE +LBB_WIDTH + .byte "IDTH",TK_WIDTH ; WIDTH + .byte $00 +TAB_POWR + .byte TK_POWER,$00 ; ^ + +; new decode table for LIST +; Table is .. +; byte - keyword length, keyword first character +; word - pointer to rest of keyword from dictionary + +; note if length is 1 then the pointer is ignored + +LAB_KEYT + .byte 3,'E' + .word LBB_END ; END + .byte 3,'F' + .word LBB_FOR ; FOR + .byte 4,'N' + .word LBB_NEXT ; NEXT + .byte 4,'D' + .word LBB_DATA ; DATA + .byte 5,'I' + .word LBB_INPUT ; INPUT + .byte 3,'D' + .word LBB_DIM ; DIM + .byte 4,'R' + .word LBB_READ ; READ + .byte 3,'L' + .word LBB_LET ; LET + .byte 3,'D' + .word LBB_DEC ; DEC + .byte 4,'G' + .word LBB_GOTO ; GOTO + .byte 3,'R' + .word LBB_RUN ; RUN + .byte 2,'I' + .word LBB_IF ; IF + .byte 7,'R' + .word LBB_RESTORE ; RESTORE + .byte 5,'G' + .word LBB_GOSUB ; GOSUB + .byte 6,'R' + .word LBB_RETIRQ ; RETIRQ + .byte 6,'R' + .word LBB_RETNMI ; RETNMI + .byte 6,'R' + .word LBB_RETURN ; RETURN + .byte 3,'R' + .word LBB_REM ; REM + .byte 4,'S' + .word LBB_STOP ; STOP + .byte 2,'O' + .word LBB_ON ; ON + .byte 4,'N' + .word LBB_NULL ; NULL + .byte 3,'I' + .word LBB_INC ; INC + .byte 4,'W' + .word LBB_WAIT ; WAIT + .byte 4,'L' + .word LBB_LOAD ; LOAD + .byte 4,'S' + .word LBB_SAVE ; SAVE + .byte 3,'D' + .word LBB_DEF ; DEF + .byte 4,'P' + .word LBB_POKE ; POKE + .byte 4,'D' + .word LBB_DOKE ; DOKE + .byte 4,'C' + .word LBB_CALL ; CALL + .byte 2,'D' + .word LBB_DO ; DO + .byte 4,'L' + .word LBB_LOOP ; LOOP + .byte 5,'P' + .word LBB_PRINT ; PRINT + .byte 4,'C' + .word LBB_CONT ; CONT + .byte 4,'L' + .word LBB_LIST ; LIST + .byte 5,'C' + .word LBB_CLEAR ; CLEAR + .byte 3,'N' + .word LBB_NEW ; NEW + .byte 5,'W' + .word LBB_WIDTH ; WIDTH + .byte 3,'G' + .word LBB_GET ; GET + .byte 4,'S' + .word LBB_SWAP ; SWAP + .byte 6,'B' + .word LBB_BITSET ; BITSET + .byte 6,'B' + .word LBB_BITCLR ; BITCLR + .byte 3,'I' + .word LBB_IRQ ; IRQ + .byte 3,'N' + .word LBB_NMI ; NMI + +; secondary commands (can't start a statement) + + .byte 4,'T' + .word LBB_TAB ; TAB + .byte 4,'E' + .word LBB_ELSE ; ELSE + .byte 2,'T' + .word LBB_TO ; TO + .byte 2,'F' + .word LBB_FN ; FN + .byte 4,'S' + .word LBB_SPC ; SPC + .byte 4,'T' + .word LBB_THEN ; THEN + .byte 3,'N' + .word LBB_NOT ; NOT + .byte 4,'S' + .word LBB_STEP ; STEP + .byte 5,'U' + .word LBB_UNTIL ; UNTIL + .byte 5,'W' + .word LBB_WHILE ; WHILE + .byte 3,'O' + .word LBB_OFF ; OFF + +; opperators + + .byte 1,'+' + .word $0000 ; + + .byte 1,'-' + .word $0000 ; - + .byte 1,'*' + .word $0000 ; * + .byte 1,'/' + .word $0000 ; / + .byte 1,'^' + .word $0000 ; ^ + .byte 3,'A' + .word LBB_AND ; AND + .byte 3,'E' + .word LBB_EOR ; EOR + .byte 2,'O' + .word LBB_OR ; OR + .byte 2,'>' + .word LBB_RSHIFT ; >> + .byte 2,'<' + .word LBB_LSHIFT ; << + .byte 1,'>' + .word $0000 ; > + .byte 1,'=' + .word $0000 ; = + .byte 1,'<' + .word $0000 ; < + +; functions + + .byte 4,'S' ; + .word LBB_SGN ; SGN + .byte 4,'I' ; + .word LBB_INT ; INT + .byte 4,'A' ; + .word LBB_ABS ; ABS + .byte 4,'U' ; + .word LBB_USR ; USR + .byte 4,'F' ; + .word LBB_FRE ; FRE + .byte 4,'P' ; + .word LBB_POS ; POS + .byte 4,'S' ; + .word LBB_SQR ; SQR + .byte 4,'R' ; + .word LBB_RND ; RND + .byte 4,'L' ; + .word LBB_LOG ; LOG + .byte 4,'E' ; + .word LBB_EXP ; EXP + .byte 4,'C' ; + .word LBB_COS ; COS + .byte 4,'S' ; + .word LBB_SIN ; SIN + .byte 4,'T' ; + .word LBB_TAN ; TAN + .byte 4,'A' ; + .word LBB_ATN ; ATN + .byte 5,'P' ; + .word LBB_PEEK ; PEEK + .byte 5,'D' ; + .word LBB_DEEK ; DEEK + .byte 5,'S' ; + .word LBB_SADD ; SADD + .byte 4,'L' ; + .word LBB_LEN ; LEN + .byte 5,'S' ; + .word LBB_STRS ; STR$ + .byte 4,'V' ; + .word LBB_VAL ; VAL + .byte 4,'A' ; + .word LBB_ASC ; ASC + .byte 7,'U' ; + .word LBB_UCASES ; UCASE$ + .byte 7,'L' ; + .word LBB_LCASES ; LCASE$ + .byte 5,'C' ; + .word LBB_CHRS ; CHR$ + .byte 5,'H' ; + .word LBB_HEXS ; HEX$ + .byte 5,'B' ; + .word LBB_BINS ; BIN$ + .byte 7,'B' ; + .word LBB_BITTST ; BITTST + .byte 4,'M' ; + .word LBB_MAX ; MAX + .byte 4,'M' ; + .word LBB_MIN ; MIN + .byte 2,'P' ; + .word LBB_PI ; PI + .byte 5,'T' ; + .word LBB_TWOPI ; TWOPI + .byte 7,'V' ; + .word LBB_VPTR ; VARPTR + .byte 6,'L' ; + .word LBB_LEFTS ; LEFT$ + .byte 7,'R' ; + .word LBB_RIGHTS ; RIGHT$ + .byte 5,'M' ; + .word LBB_MIDS ; MID$ + +; BASIC messages, mostly error messages + +LAB_BAER + .word ERR_NF ;$00 NEXT without FOR + .word ERR_SN ;$02 syntax + .word ERR_RG ;$04 RETURN without GOSUB + .word ERR_OD ;$06 out of data + .word ERR_FC ;$08 function call + .word ERR_OV ;$0A overflow + .word ERR_OM ;$0C out of memory + .word ERR_US ;$0E undefined statement + .word ERR_BS ;$10 array bounds + .word ERR_DD ;$12 double dimension array + .word ERR_D0 ;$14 divide by 0 + .word ERR_ID ;$16 illegal direct + .word ERR_TM ;$18 type mismatch + .word ERR_LS ;$1A long string + .word ERR_ST ;$1C string too complex + .word ERR_CN ;$1E continue error + .word ERR_UF ;$20 undefined function + .word ERR_LD ;$22 LOOP without DO + +; I may implement these two errors to force definition of variables and +; dimensioning of arrays before use. + +; .word ERR_UV ;$24 undefined variable + +; the above error has been tested and works (see code and comments below LAB_1D8B) + +; .word ERR_UA ;$26 undimensioned array + +ERR_NF .byte "NEXT without FOR",$00 +ERR_SN .byte "Syntax",$00 +ERR_RG .byte "RETURN without GOSUB",$00 +ERR_OD .byte "Out of DATA",$00 +ERR_FC .byte "Function call",$00 +ERR_OV .byte "Overflow",$00 +ERR_OM .byte "Out of memory",$00 +ERR_US .byte "Undefined statement",$00 +ERR_BS .byte "Array bounds",$00 +ERR_DD .byte "Double dimension",$00 +ERR_D0 .byte "Divide by zero",$00 +ERR_ID .byte "Illegal direct",$00 +ERR_TM .byte "Type mismatch",$00 +ERR_LS .byte "String too long",$00 +ERR_ST .byte "String too complex",$00 +ERR_CN .byte "Can't continue",$00 +ERR_UF .byte "Undefined function",$00 +ERR_LD .byte "LOOP without DO",$00 + +;ERR_UV .byte "Undefined variable",$00 + +; the above error has been tested and works (see code and comments below LAB_1D8B) + +;ERR_UA .byte "Undimensioned array",$00 + +LAB_BMSG .byte $0D,$0A,"Break",$00 +LAB_EMSG .byte " Error",$00 +LAB_LMSG .byte " in line ",$00 +LAB_RMSG .byte $0D,$0A,"Ready",$0D,$0A,$00 + +LAB_IMSG .byte " Extra ignored",$0D,$0A,$00 +LAB_REDO .byte " Redo from start",$0D,$0A,$00 + +AA_end_basic diff --git a/min_mon.asm b/min_mon.asm new file mode 100644 index 0000000..7695c01 --- /dev/null +++ b/min_mon.asm @@ -0,0 +1,134 @@ + +; minimal monitor for EhBASIC and 6502 simulator V1.05 + +; To run EhBASIC on the simulator load and assemble [F7] this file, start the simulator +; running [F6] then start the code with the RESET [CTRL][SHIFT]R. Just selecting RUN +; will do nothing, you'll still have to do a reset to run the code. + + .include "basic.asm" + +; put the IRQ and MNI code in RAM so that it can be changed + +IRQ_vec = VEC_SV+2 ; IRQ code vector +NMI_vec = IRQ_vec+$0A ; NMI code vector + +; setup for the 6502 simulator environment + +IO_AREA = $F000 ; set I/O area for this monitor + +ACIAsimwr = IO_AREA+$01 ; simulated ACIA write port +ACIAsimrd = IO_AREA+$04 ; simulated ACIA read port + +; now the code. all this does is set up the vectors and interrupt code +; and wait for the user to select [C]old or [W]arm start. nothing else +; fits in less than 128 bytes + + *= $FF80 ; pretend this is in a 1/8K ROM + +; reset vector points here + +RES_vec + CLD ; clear decimal mode + LDX #$FF ; empty stack + TXS ; set the stack + +; set up vectors and interrupt code, copy them to page 2 + + LDY #END_CODE-LAB_vec ; set index/count +LAB_stlp + LDA LAB_vec-1,Y ; get byte from interrupt code + STA VEC_IN-1,Y ; save to RAM + DEY ; decrement index/count + BNE LAB_stlp ; loop if more to do + +; now do the signon message, Y = $00 here + +LAB_signon + LDA LAB_mess,Y ; get byte from sign on message + BEQ LAB_nokey ; exit loop if done + + JSR V_OUTP ; output character + INY ; increment index + BNE LAB_signon ; loop, branch always + +LAB_nokey + JSR V_INPT ; call scan input device + BCC LAB_nokey ; loop if no key + + AND #$DF ; mask xx0x xxxx, ensure upper case + CMP #'W' ; compare with [W]arm start + BEQ LAB_dowarm ; branch if [W]arm start + + CMP #'C' ; compare with [C]old start + BNE RES_vec ; loop if not [C]old start + + JMP LAB_COLD ; do EhBASIC cold start + +LAB_dowarm + JMP LAB_WARM ; do EhBASIC warm start + +; byte out to simulated ACIA + +ACIAout + STA ACIAsimwr ; save byte to simulated ACIA + RTS + +; byte in from simulated ACIA + +ACIAin + LDA ACIAsimrd ; get byte from simulated ACIA + BEQ LAB_nobyw ; branch if no byte waiting + + SEC ; flag byte received + RTS + +LAB_nobyw + CLC ; flag no byte received +no_load ; empty load vector for EhBASIC +no_save ; empty save vector for EhBASIC + RTS + +; vector tables + +LAB_vec + .word ACIAin ; byte in from simulated ACIA + .word ACIAout ; byte out to simulated ACIA + .word no_load ; null load vector for EhBASIC + .word no_save ; null save vector for EhBASIC + +; EhBASIC IRQ support + +IRQ_CODE + PHA ; save A + LDA IrqBase ; get the IRQ flag byte + LSR ; shift the set b7 to b6, and on down ... + ORA IrqBase ; OR the original back in + STA IrqBase ; save the new IRQ flag byte + PLA ; restore A + RTI + +; EhBASIC NMI support + +NMI_CODE + PHA ; save A + LDA NmiBase ; get the NMI flag byte + LSR ; shift the set b7 to b6, and on down ... + ORA NmiBase ; OR the original back in + STA NmiBase ; save the new NMI flag byte + PLA ; restore A + RTI + +END_CODE + +LAB_mess + .byte $0D,$0A,"6502 EhBASIC [C]old/[W]arm ?",$00 + ; sign on string + +; system vectors + + *= $FFFA + + .word NMI_vec ; NMI vector + .word RES_vec ; RESET vector + .word IRQ_vec ; IRQ vector + diff --git a/readme.txt b/readme.txt new file mode 100644 index 0000000..68fd373 --- /dev/null +++ b/readme.txt @@ -0,0 +1,15 @@ + + Enhanced BASIC is a BASIC interpreter for the 6502 family microprocessors. It + is constructed to be quick and powerful and easily ported between 6502 systems. + It requires few resources to run and includes instructions to facilitate easy + low level handling of hardware devices. It also retains most of the powerful + high level instructions from similar BASICs. + + EhBASIC is free but not copyright free. For non commercial use there is only one + restriction, any derivative work should include, in any binary image distributed, + the string "Derived from EhBASIC" and in any distribution that includes human + readable files a file that includes the above string in a human readable form + e.g. not as a comment in an HTML file. + + For commercial use please contact Lee Davison at leeedavison@googlemail.com + for conditions.