; IL65 definitions for the Commodore-64 ; Including memory registers, I/O registers, Basic and Kernal subroutines, utility subroutines. ; ; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0 ; ; ; indent format: TABS, size=8 %option enable_floats ~ c64 { memory byte SCRATCH_ZP1 = $02 ; scratch register #1 in ZP memory byte SCRATCH_ZP2 = $03 ; scratch register #2 in ZP memory word SCRATCH_ZPWORD1 = $fb ; scratch word in ZP ($fb/$fc) memory word SCRATCH_ZPWORD2 = $fd ; scratch word in ZP ($fd/$fe) memory byte TIME_HI = $a0 ; software jiffy clock, hi byte memory byte TIME_MID = $a1 ; .. mid byte memory byte TIME_LO = $a2 ; .. lo byte. Updated by IRQ every 1/60 sec memory byte STKEY = $91 ; various keyboard statuses (updated by IRQ) memory byte SFDX = $cb ; current key pressed (matrix value) (updated by IRQ) memory byte COLOR = $0286 ; cursor color memory byte HIBASE = $0288 ; screen base address / 256 (hi-byte of screen memory address) memory word CINV = $0314 ; IRQ vector memory word NMI_VEC = $FFFA ; 6502 nmi vector, determined by the kernal if banked in memory word RESET_VEC = $FFFC ; 6502 reset vector, determined by the kernal if banked in memory word IRQ_VEC = $FFFE ; 6502 interrupt vector, determined by the kernal if banked in memory byte[40, 25] Screen = $0400 ; default character screen matrix memory byte[40, 25] Colors = $d800 ; character screen colors ; ---- VIC-II registers ---- memory byte SP0X = $d000 memory byte SP0Y = $d001 memory byte SP1X = $d002 memory byte SP1Y = $d003 memory byte SP2X = $d004 memory byte SP2Y = $d005 memory byte SP3X = $d006 memory byte SP3Y = $d007 memory byte SP4X = $d008 memory byte SP4Y = $d009 memory byte SP5X = $d00a memory byte SP5Y = $d00b memory byte SP6X = $d00c memory byte SP6Y = $d00d memory byte SP7X = $d00e memory byte SP7Y = $d00f memory byte MSIGX = $d010 memory byte SCROLY = $d011 memory byte RASTER = $d012 memory byte LPENX = $d013 memory byte LPENY = $d014 memory byte SPENA = $d015 memory byte SCROLX = $d016 memory byte YXPAND = $d017 memory byte VMCSB = $d018 memory byte VICIRQ = $d019 memory byte IREQMASK = $d01a memory byte SPBGPR = $d01b memory byte SPMC = $d01c memory byte XXPAND = $d01d memory byte SPSPCL = $d01e memory byte SPBGCL = $d01f memory byte EXTCOL = $d020 ; border color memory byte BGCOL0 = $d021 ; screen color memory byte BGCOL1 = $d022 memory byte BGCOL2 = $d023 memory byte BGCOL4 = $d024 memory byte SPMC0 = $d025 memory byte SPMC1 = $d026 memory byte SP0COL = $d027 memory byte SP1COL = $d028 memory byte SP2COL = $d029 memory byte SP3COL = $d02a memory byte SP4COL = $d02b memory byte SP5COL = $d02c memory byte SP6COL = $d02d memory byte SP7COL = $d02e ; ---- end of VIC-II registers ---- ; ---- C64 basic and kernal ROM float constants and functions ---- ; note: the fac1 and fac2 are working registers and take 6 bytes each, ; floats in memory (and rom) are stored in 5-byte MFLPT packed format. ; constants in five-byte "mflpt" format in the BASIC ROM memory float FL_PIVAL = $aea8 ; 3.1415926... memory float FL_N32768 = $b1a5 ; -32768 memory float FL_FONE = $b9bc ; 1 memory float FL_SQRHLF = $b9d6 ; SQR(2) / 2 memory float FL_SQRTWO = $b9db ; SQR(2) memory float FL_NEGHLF = $b9e0 ; -.5 memory float FL_LOG2 = $b9e5 ; LOG(2) memory float FL_TENC = $baf9 ; 10 memory float FL_NZMIL = $bdbd ; 1e9 (1 billion) memory float FL_FHALF = $bf11 ; .5 memory float FL_LOGEB2 = $bfbf ; 1 / LOG(2) memory float FL_PIHALF = $e2e0 ; PI / 2 memory float FL_TWOPI = $e2e5 ; 2 * PI memory float FL_FR4 = $e2ea ; .25 ; note: fac1/2 might get clobbered even if not mentioned in the function's name. ; note: for subtraction and division, the left operand is in fac2, the right operand in fac1. ; checked functions below: sub MOVFM (mflpt: AY) -> (A?, Y?) = $bba2 ; load mflpt value from memory in A/Y into fac1 sub FREADMEM () -> (A?, Y?) = $bba6 ; load mflpt value from memory in $22/$23 into fac1 sub CONUPK (mflpt: AY) -> (A?, Y?) = $ba8c ; load mflpt value from memory in A/Y into fac2 sub FAREADMEM () -> (A?, Y?) = $ba90 ; load mflpt value from memory in $22/$23 into fac2 sub MOVFA () -> (A?, X?) = $bbfc ; copy fac2 to fac1 sub MOVAF () -> (A?, X?) = $bc0c ; copy fac1 to fac2 (rounded) sub MOVEF () -> (A?, X?) = $bc0f ; copy fac1 to fac2 sub FTOMEMXY (mflpt: XY) -> (A?, Y?) = $bbd4 ; store fac1 to memory X/Y as 5-byte mflpt ; fac1-> signed word in Y/A (might throw ILLEGAL QUANTITY) ; (use c64flt.FTOSWRDAY to get A/Y output; lo/hi switched to normal order) sub FTOSWORDYA () -> (Y, A, X?) = $b1aa ; fac1 -> unsigned word in Y/A (might throw ILLEGAL QUANTITY) (result also in $14/15) ; (use c64flt.GETADRAY to get A/Y output; lo/hi switched to normal order) sub GETADR () -> (Y, A, X?) = $b7f7 sub QINT () -> (?) = $bc9b ; fac1 -> 4-byte signed integer in 98-101 ($62-$65), with the MSB FIRST. sub AYINT () -> (?) = $b1bf ; fac1-> signed word in 100-101 ($64-$65) MSB FIRST. (might throw ILLEGAL QUANTITY) ; signed word in Y/A -> float in fac1 ; (use c64flt.GIVAYFAY to use A/Y input; lo/hi switched to normal order) ; there is also c64flt.GIVUAYF - unsigned word in A/Y (lo/hi) to fac1 ; there is also c64flt.FREADS32 that reads from 98-101 ($62-$65) MSB FIRST ; there is also c64flt.FREADUS32 that reads from 98-101 ($62-$65) MSB FIRST ; there is also c64flt.FREADS24AXY that reads signed int24 into fac1 from A/X/Y (lo/mid/hi bytes) sub GIVAYF (lo: Y, hi: A) -> (?) = $b391 sub FREADUY (ubyte: Y) -> (?) = $b3a2 ; 8 bit unsigned Y -> float in fac1 sub FREADSA (sbyte: A) -> (?) = $bc3c ; 8 bit signed A -> float in fac1 sub FREADSTR (len: A) -> (?) = $b7b5 ; str -> fac1, $22/23 must point to string, A=string length sub FPRINTLN () -> (?) = $aabc ; print string of fac1, on one line (= with newline) sub FOUT () -> (AY, X?) = $bddd ; fac1 -> string, address returned in AY ($0100) sub FADDH () -> (?) = $b849 ; fac1 += 0.5, for rounding- call this before INT sub MUL10 () -> (?) = $bae2 ; fac1 *= 10 sub DIV10 () -> (?) = $bafe ; fac1 /= 10 , CAUTION: result is always positive! sub FCOMP (mflpt: AY) -> (A, X?, Y?) = $bc5b ; A = compare fac1 to mflpt in A/Y, 0=equal 1=fac1 is greater, 255=fac1 is less than sub FADDT () -> (?) = $b86a ; fac1 += fac2 sub FADD (mflpt: AY) -> (?) = $b867 ; fac1 += mflpt value from A/Y sub FSUBT () -> (?) = $b853 ; fac1 = fac2-fac1 mind the order of the operands sub FSUB (mflpt: AY) -> (?) = $b850 ; fac1 = mflpt from A/Y - fac1 sub FMULTT () -> (?) = $ba2b ; fac1 *= fac2 sub FMULT (mflpt: AY) -> (?) = $ba28 ; fac1 *= mflpt value from A/Y sub FDIVT () -> (?) = $bb12 ; fac1 = fac2/fac1 mind the order of the operands sub FDIV (mflpt: AY) -> (?) = $bb0f ; fac1 = mflpt in A/Y / fac1 sub FPWRT () -> (?) = $bf7b ; fac1 = fac2 ** fac1 sub FPWR (mflpt: AY) -> (?) = $bf78 ; fac1 = fac2 ** mflpt from A/Y sub NOTOP () -> (?) = $aed4 ; fac1 = NOT(fac1) sub INT () -> (?) = $bccc ; INT() truncates, use FADDH first to round instead of trunc sub LOG () -> (?) = $b9ea ; fac1 = LN(fac1) (natural log) sub SGN () -> (?) = $bc39 ; fac1 = SGN(fac1), result of SIGN (-1, 0 or 1) sub SIGN () -> (A) = $bc2b ; SIGN(fac1) to A, $ff, $0, $1 for negative, zero, positive sub ABS () -> () = $bc58 ; fac1 = ABS(fac1) sub SQR () -> (?) = $bf71 ; fac1 = SQRT(fac1) sub EXP () -> (?) = $bfed ; fac1 = EXP(fac1) (e ** fac1) sub NEGOP () -> (A?) = $bfb4 ; switch the sign of fac1 sub RND () -> (?) = $e097 ; fac1 = RND() (use RNDA instead) sub RNDA (acc: A) -> (?) = $e09a ; fac1 = RND(A) sub COS () -> (?) = $e264 ; fac1 = COS(fac1) sub SIN () -> (?) = $e26b ; fac1 = SIN(fac1) sub TAN () -> (?) = $e2b4 ; fac1 = TAN(fac1) sub ATN () -> (?) = $e30e ; fac1 = ATN(fac1) ; ---- C64 basic routines ---- sub CLEARSCR () -> (?) = $E544 ; clear the screen sub HOMECRSR () -> (?) = $E566 ; cursor to top left of screen ; ---- end of C64 basic routines ---- ; ---- C64 kernal routines ---- sub IRQDFRT () -> (?) = $EA31 ; default IRQ routine sub IRQDFEND () -> (?) = $EA81 ; default IRQ end/cleanup sub CINT () -> (?) = $FF81 ; (alias: SCINIT) initialize screen editor and video chip sub IOINIT () -> (A?, X?) = $FF84 ; initialize I/O devices (CIA, SID, IRQ) sub RAMTAS () -> (?) = $FF87 ; initialize RAM, tape buffer, screen sub RESTOR () -> (?) = $FF8A ; restore default I/O vectors sub VECTOR (dir: Pc, userptr: XY) -> (A?, Y?) = $FF8D ; read/set I/O vector table sub SETMSG (value: A) -> () = $FF90 ; set Kernal message control flag sub SECOND (address: A) -> (A?) = $FF93 ; (alias: LSTNSA) send secondary address after LISTEN sub TKSA (address: A) -> (A?) = $FF96 ; (alias: TALKSA) send secondary address after TALK sub MEMTOP (dir: Pc, address: XY) -> (XY) = $FF99 ; read/set top of memory pointer sub MEMBOT (dir: Pc, address: XY) -> (XY) = $FF9C ; read/set bottom of memory pointer sub SCNKEY () -> (?) = $FF9F ; scan the keyboard sub SETTMO (timeout: A) -> () = $FFA2 ; set time-out flag for IEEE bus sub ACPTR () -> (A) = $FFA5 ; (alias: IECIN) input byte from serial bus sub CIOUT (databyte: A) -> () = $FFA8 ; (alias: IECOUT) output byte to serial bus sub UNTLK () -> (A?) = $FFAB ; command serial bus device to UNTALK sub UNLSN () -> (A?) = $FFAE ; command serial bus device to UNLISTEN sub LISTEN (device: A) -> (A?) = $FFB1 ; command serial bus device to LISTEN sub TALK (device: A) -> (A?) = $FFB4 ; command serial bus device to TALK sub READST () -> (A) = $FFB7 ; read I/O status word sub SETLFS (logical: A, device: X, address: Y) -> () = $FFBA ; set logical file parameters sub SETNAM (namelen: A, filename: XY) -> () = $FFBD ; set filename parameters sub OPEN () -> (?) = $FFC0 ; (via 794 ($31A)) open a logical file sub CLOSE (logical: A) -> (?) = $FFC3 ; (via 796 ($31C)) close a logical file sub CHKIN (logical: X) -> (A?, X?) = $FFC6 ; (via 798 ($31E)) define an input channel sub CHKOUT (logical: X) -> (A?, X?) = $FFC9 ; (via 800 ($320)) define an output channel sub CLRCHN () -> (A?, X?) = $FFCC ; (via 802 ($322)) restore default devices sub CHRIN () -> (A, Y?) = $FFCF ; (via 804 ($324)) input a character (for keyboard, read a whole line from the screen) A=byte read. sub CHROUT (char: A) -> () = $FFD2 ; (via 806 ($326)) output a character sub LOAD (verify: A, address: XY) -> (Pc, A, X, Y) = $FFD5 ; (via 816 ($330)) load from device sub SAVE (zp_startaddr: A, endaddr: XY) -> (Pc, A) = $FFD8 ; (via 818 ($332)) save to a device sub SETTIM (low: A, middle: X, high: Y) -> () = $FFDB ; set the software clock sub RDTIM () -> (A, X, Y) = $FFDE ; read the software clock sub STOP () -> (Pz, Pc, A?, X?) = $FFE1 ; (via 808 ($328)) check the STOP key sub GETIN () -> (A, X?, Y?) = $FFE4 ; (via 810 ($32A)) get a character sub CLALL () -> (A?, X?) = $FFE7 ; (via 812 ($32C)) close all files sub UDTIM () -> (A?, X?) = $FFEA ; update the software clock sub SCREEN () -> (X, Y) = $FFED ; read number of screen rows and columns sub PLOT (dir: Pc, col: Y, row: X) -> (X, Y) = $FFF0 ; read/set position of cursor on screen sub IOBASE () -> (X, Y) = $FFF3 ; read base address of I/O devices ; ---- end of C64 kernal routines ---- ; ----- utility functions ---- sub init_system () -> (?) { ; ---- initializes the machine to a sane starting state ; This means that the BASIC, KERNAL and CHARGEN ROMs are banked in, ; the VIC, SID and CIA chips are reset, screen is cleared, and the default IRQ is set. ; Also a different color scheme is chosen to identify ourselves a little. %asm {{ sei cld lda #%00101111 sta $00 lda #%00100111 sta $01 jsr c64.IOINIT jsr c64.RESTOR jsr c64.CINT lda #6 sta c64.EXTCOL lda #7 sta c64.COLOR lda #0 sta c64.BGCOL0 tax tay clc clv cli rts }} } } ; ------ end of block c64 ~ c64flt { ; ---- this block contains C-64 floating point related functions ---- sub FREADS32 () -> (?) { ; ---- fac1 = signed int32 from $62-$65 big endian (MSB FIRST) %asm {{ lda $62 eor #$ff asl a lda #0 ldx #$a0 jmp $bc4f ; internal BASIC routine }} } sub FREADUS32 () -> (?) { ; ---- fac1 = uint32 from $62-$65 big endian (MSB FIRST) %asm {{ sec lda #0 ldx #$a0 jmp $bc4f ; internal BASIC routine }} } sub FREADS24AXY (lo: A, mid: X, hi: Y) -> (?) { ; ---- fac1 = signed int24 (A/X/Y contain lo/mid/hi bytes) ; note: there is no FREADU24AXY (unsigned), use FREADUS32 instead. %asm {{ sty $62 stx $63 sta $64 lda $62 eor #$FF asl a lda #0 sta $65 ldx #$98 jmp $bc4f ; internal BASIC routine }} } sub GIVUAYF (uword: AY) -> (?) { ; ---- unsigned 16 bit word in A/Y (lo/hi) to fac1 %asm {{ sty $62 sta $63 ldx #$90 sec jmp $bc49 ; internal BASIC routine }} } sub GIVAYFAY (sword: AY) -> (?) { ; ---- signed 16 bit word in A/Y (lo/hi) to float in fac1 %asm {{ sta c64.SCRATCH_ZP1 tya ldy c64.SCRATCH_ZP1 jmp c64.GIVAYF ; this uses the inverse order, Y/A }} } sub FTOSWRDAY () -> (AY, X?) { ; ---- fac1 to signed word in A/Y %asm {{ jsr c64.FTOSWORDYA ; note the inverse Y/A order sta c64.SCRATCH_ZP1 tya ldy c64.SCRATCH_ZP1 rts }} } sub GETADRAY () -> (AY, X?) { ; ---- fac1 to unsigned word in A/Y %asm {{ jsr c64.GETADR ; this uses the inverse order, Y/A sta c64.SCRATCH_ZP1 tya ldy c64.SCRATCH_ZP1 rts }} } sub copy_mflt (source: XY) -> (A?, Y?) { ; ---- copy a 5 byte MFLT floating point variable to another place ; input: X/Y = source address, c64.SCRATCH_ZPWORD1 = destination address %asm {{ stx c64.SCRATCH_ZP1 sty c64.SCRATCH_ZPWORD1+1 ldy #0 lda (c64.SCRATCH_ZP1),y sta (c64.SCRATCH_ZPWORD1),y iny lda (c64.SCRATCH_ZP1),y sta (c64.SCRATCH_ZPWORD1),y iny lda (c64.SCRATCH_ZP1),y sta (c64.SCRATCH_ZPWORD1),y iny lda (c64.SCRATCH_ZP1),y sta (c64.SCRATCH_ZPWORD1),y iny lda (c64.SCRATCH_ZP1),y sta (c64.SCRATCH_ZPWORD1),y ldy c64.SCRATCH_ZPWORD1+1 rts }} } sub float_add_one (mflt: XY) -> (?) { ; ---- add 1 to the MFLT pointed to by X/Y. Clobbers A, X, Y %asm {{ stx c64.SCRATCH_ZP1 sty c64.SCRATCH_ZP2 txa jsr c64.MOVFM ; fac1 = float XY lda #c64.FL_FONE jsr c64.FADD ; fac1 += 1 ldx c64.SCRATCH_ZP1 ldy c64.SCRATCH_ZP2 jmp c64.FTOMEMXY ; float XY = fac1 }} } sub float_sub_one (mflt: XY) -> (?) { ; ---- subtract 1 from the MFLT pointed to by X/Y. Clobbers A, X, Y %asm {{ stx c64.SCRATCH_ZP1 sty c64.SCRATCH_ZP2 lda #c64.FL_FONE jsr c64.MOVFM ; fac1 = 1 txa ldy c64.SCRATCH_ZP2 jsr c64.FSUB ; fac1 = float XY - 1 ldx c64.SCRATCH_ZP1 ldy c64.SCRATCH_ZP2 jmp c64.FTOMEMXY ; float XY = fac1 }} } sub float_add_SW1_to_XY (mflt: XY) -> (?) { ; ---- add MFLT pointed to by SCRATCH_ZPWORD1 to the MFLT pointed to by X/Y. Clobbers A, X, Y %asm {{ stx c64.SCRATCH_ZP1 sty c64.SCRATCH_ZP2 txa jsr c64.MOVFM ; fac1 = float XY lda c64.SCRATCH_ZPWORD1 ldy c64.SCRATCH_ZPWORD1+1 jsr c64.FADD ; fac1 += SCRATCH_ZPWORD1 ldx c64.SCRATCH_ZP1 ldy c64.SCRATCH_ZP2 jmp c64.FTOMEMXY ; float XY = fac1 }} } sub float_sub_SW1_from_XY (mflt: XY) -> (?) { ; ---- subtract MFLT pointed to by SCRATCH_ZPWORD1 from the MFLT pointed to by X/Y. Clobbers A, X, Y %asm {{ stx c64.SCRATCH_ZP1 sty c64.SCRATCH_ZP2 lda c64.SCRATCH_ZPWORD1 ldy c64.SCRATCH_ZPWORD1+1 jsr c64.MOVFM ; fac1 = SCRATCH_ZPWORD1 txa ldy c64.SCRATCH_ZP2 jsr c64.FSUB ; fac1 = float XY - SCRATCH_ZPWORD1 ldx c64.SCRATCH_ZP1 ldy c64.SCRATCH_ZP2 jmp c64.FTOMEMXY ; float XY = fac1 }} } } ; ------ end of block c64flt ~ c64scr { ; ---- this block contains (character) Screen and text I/O related functions ---- sub clear_screen (char: A, color: Y) -> () { ; ---- clear the character screen with the given fill character and character color. ; (assumes screen is at $0400, could be altered in the future with self-modifying code) ; @todo some byte var to set the SCREEN ADDR HI BYTE %asm {{ sta _loop + 1 ; self-modifying stx c64.SCRATCH_ZP1 ldx #0 _loop lda #0 sta c64.Screen,x sta c64.Screen+$0100,x sta c64.Screen+$0200,x sta c64.Screen+$02e8,x tya sta c64.Colors,x sta c64.Colors+$0100,x sta c64.Colors+$0200,x sta c64.Colors+$02e8,x inx bne _loop lda _loop+1 ; restore A and X ldx c64.SCRATCH_ZP1 rts }} } sub scroll_left_full (alsocolors: Pc) -> (A?, X?, Y?) { ; ---- scroll the whole screen 1 character to the left ; contents of the rightmost column are unchanged, you should clear/refill this yourself ; Carry flag determines if screen color data must be scrolled too %asm {{ bcs + jmp _scroll_screen + ; scroll the color memory ldx #0 ldy #38 - .for row=0, row<=12, row+=1 lda c64.Colors + 40*row + 1,x sta c64.Colors + 40*row,x .next inx dey bpl - ldx #0 ldy #38 - .for row=13, row<=24, row+=1 lda c64.Colors + 40*row + 1,x sta c64.Colors + 40*row,x .next inx dey bpl - _scroll_screen ; scroll the screen memory ldx #0 ldy #38 - .for row=0, row<=12, row+=1 lda c64.Screen + 40*row + 1,x sta c64.Screen + 40*row,x .next inx dey bpl - ldx #0 ldy #38 - .for row=13, row<=24, row+=1 lda c64.Screen + 40*row + 1,x sta c64.Screen + 40*row,x .next inx dey bpl - rts }} } sub scroll_right_full (alsocolors: Pc) -> (A?, X?) { ; ---- scroll the whole screen 1 character to the right ; contents of the leftmost column are unchanged, you should clear/refill this yourself ; Carry flag determines if screen color data must be scrolled too %asm {{ bcs + jmp _scroll_screen + ; scroll the color memory ldx #38 - .for row=0, row<=12, row+=1 lda c64.Colors + 40*row + 0,x sta c64.Colors + 40*row + 1,x .next dex bpl - ldx #38 - .for row=13, row<=24, row+=1 lda c64.Colors + 40*row,x sta c64.Colors + 40*row + 1,x .next dex bpl - _scroll_screen ; scroll the screen memory ldx #38 - .for row=0, row<=12, row+=1 lda c64.Screen + 40*row + 0,x sta c64.Screen + 40*row + 1,x .next dex bpl - ldx #38 - .for row=13, row<=24, row+=1 lda c64.Screen + 40*row,x sta c64.Screen + 40*row + 1,x .next dex bpl - rts }} } sub scroll_up_full (alsocolors: Pc) -> (A?, X?) { ; ---- scroll the whole screen 1 character up ; contents of the bottom row are unchanged, you should refill/clear this yourself ; Carry flag determines if screen color data must be scrolled too %asm {{ bcs + jmp _scroll_screen + ; scroll the color memory ldx #39 - .for row=1, row<=11, row+=1 lda c64.Colors + 40*row,x sta c64.Colors + 40*(row-1),x .next dex bpl - ldx #39 - .for row=12, row<=24, row+=1 lda c64.Colors + 40*row,x sta c64.Colors + 40*(row-1),x .next dex bpl - _scroll_screen ; scroll the screen memory ldx #39 - .for row=1, row<=11, row+=1 lda c64.Screen + 40*row,x sta c64.Screen + 40*(row-1),x .next dex bpl - ldx #39 - .for row=12, row<=24, row+=1 lda c64.Screen + 40*row,x sta c64.Screen + 40*(row-1),x .next dex bpl - rts }} } sub scroll_down_full (alsocolors: Pc) -> (A?, X?) { ; ---- scroll the whole screen 1 character down ; contents of the top row are unchanged, you should refill/clear this yourself ; Carry flag determines if screen color data must be scrolled too %asm {{ bcs + jmp _scroll_screen + ; scroll the color memory ldx #39 - .for row=23, row>=12, row-=1 lda c64.Colors + 40*row,x sta c64.Colors + 40*(row+1),x .next dex bpl - ldx #39 - .for row=11, row>=0, row-=1 lda c64.Colors + 40*row,x sta c64.Colors + 40*(row+1),x .next dex bpl - _scroll_screen ; scroll the screen memory ldx #39 - .for row=23, row>=12, row-=1 lda c64.Screen + 40*row,x sta c64.Screen + 40*(row+1),x .next dex bpl - ldx #39 - .for row=11, row>=0, row-=1 lda c64.Screen + 40*row,x sta c64.Screen + 40*(row+1),x .next dex bpl - rts }} } sub byte2decimal (ubyte: A) -> (Y, X, A) { ; ---- A to decimal string in Y/X/A (100s in Y, 10s in X, 1s in A) %asm {{ ldy #$2f ldx #$3a sec - iny sbc #100 bcs - - dex adc #10 bmi - adc #$2f rts }} } sub byte2hex (ubyte: A) -> (X, Y, A?) { ; ---- A to hex string in XY (first hex char in X, second hex char in Y) %asm {{ pha and #$0f tax ldy hex_digits,x pla lsr a lsr a lsr a lsr a tax lda hex_digits,x tax rts hex_digits .str "0123456789abcdef" ; can probably be reused for other stuff as well }} } str word2hex_output = "1234" ; 0-terminated, to make printing easier sub word2hex (dataword: XY) -> (?) { ; ---- convert 16 bit word in X/Y into 4-character hexadecimal string into memory 'word2hex_output' %asm {{ stx c64.SCRATCH_ZP2 tya jsr byte2hex stx word2hex_output sty word2hex_output+1 lda c64.SCRATCH_ZP2 jsr byte2hex stx word2hex_output+2 sty word2hex_output+3 rts }} } byte[3] word2bcd_bcdbuff = [0, 0, 0] sub word2bcd (dataword: XY) -> (A?, X?) { ; Convert an 16 bit binary value to BCD ; ; This function converts a 16 bit binary value in X/Y into a 24 bit BCD. It ; works by transferring one bit a time from the source and adding it ; into a BCD value that is being doubled on each iteration. As all the ; arithmetic is being done in BCD the result is a binary to decimal ; conversion. %asm {{ stx c64.SCRATCH_ZP1 sty c64.SCRATCH_ZP2 sed ; switch to decimal mode lda #0 ; ensure the result is clear sta word2bcd_bcdbuff+0 sta word2bcd_bcdbuff+1 sta word2bcd_bcdbuff+2 ldx #16 ; the number of source bits - asl c64.SCRATCH_ZP1 ; shift out one bit rol c64.SCRATCH_ZP2 lda word2bcd_bcdbuff+0 ; and add into result adc word2bcd_bcdbuff+0 sta word2bcd_bcdbuff+0 lda word2bcd_bcdbuff+1 ; propagating any carry adc word2bcd_bcdbuff+1 sta word2bcd_bcdbuff+1 lda word2bcd_bcdbuff+2 ; ... thru whole result adc word2bcd_bcdbuff+2 sta word2bcd_bcdbuff+2 dex ; and repeat for next bit bne - cld ; back to binary rts }} } byte[5] word2decimal_output = 0 sub word2decimal (dataword: XY) -> (?) { ; ---- convert 16 bit word in X/Y into decimal string into memory 'word2decimal_output' %asm {{ jsr word2bcd lda word2bcd_bcdbuff+2 clc adc #'0' sta word2decimal_output ldy #1 lda word2bcd_bcdbuff+1 jsr + lda word2bcd_bcdbuff+0 + pha lsr a lsr a lsr a lsr a clc adc #'0' sta word2decimal_output,y iny pla and #$0f adc #'0' sta word2decimal_output,y iny rts }} } ; @todo string to 32 bit unsigned integer http://www.6502.org/source/strings/ascii-to-32bit.html sub print_string (address: XY) -> (A?, Y?) { ; ---- print null terminated string from X/Y ; note: the IL65 compiler contains an optimization that will replace ; a call to this subroutine with a string argument of just one char, ; by just one call to c64.CHROUT of that single char. %asm {{ stx c64.SCRATCH_ZP1 sty c64.SCRATCH_ZP2 ldy #0 - lda (c64.SCRATCH_ZP1),y beq + jsr c64.CHROUT iny bne - + rts }} } sub print_pstring (address: XY) -> (A?, X?, Y) { ; ---- print pstring (length as first byte) from X/Y, returns str len in Y %asm {{ stx c64.SCRATCH_ZP1 sty c64.SCRATCH_ZP2 ldy #0 lda (c64.SCRATCH_ZP1),y beq + tax - iny lda (c64.SCRATCH_ZP1),y jsr c64.CHROUT dex bne - + rts ; output string length is in Y }} } sub print_pimmediate () -> () { ; ---- print pstring in memory immediately following the subroutine fast call instruction ; note that the clobbered registers (A,X,Y) are not listed ON PURPOSE %asm {{ tsx lda $102,x tay ; put high byte in y lda $101,x tax ; and low byte in x. inx bne + iny + jsr print_pstring ; print string in XY, returns string length in y. tya tsx clc adc $101,x ; add content of 1st (length) byte to return addr. bcc + ; if that made the low byte roll over to 00, inc $102,x ; then increment the high byte too. + clc adc #1 ; now add 1 for the length byte itself. sta $101,x bne + ; if that made it (the low byte) roll over to 00, inc $102,x ; increment the high byte of the return addr too. + rts }} } sub print_byte_decimal0 (ubyte: A) -> (?) { ; ---- print the byte in A in decimal form, with left padding 0s (3 positions total) %asm {{ jsr byte2decimal pha tya jsr c64.CHROUT txa jsr c64.CHROUT pla jmp c64.CHROUT }} } sub print_byte_decimal (ubyte: A) -> (?) { ; ---- print the byte in A in decimal form, without left padding 0s %asm {{ jsr byte2decimal pha cpy #'0' bne _print_hundreds cpx #'0' bne _print_tens pla jmp c64.CHROUT _print_hundreds tya jsr c64.CHROUT _print_tens txa jsr c64.CHROUT pla jmp c64.CHROUT }} } sub print_byte_hex (prefix: Pc, ubyte: A) -> (?) { ; ---- print the byte in A in hex form (if Carry is set, a radix prefix '$' is printed as well) %asm {{ bcc + pha lda #'$' jsr c64.CHROUT pla + jsr byte2hex txa jsr c64.CHROUT tya jmp c64.CHROUT }} } sub print_word_hex (prefix: Pc, dataword: XY) -> (?) { ; ---- print the (unsigned) word in X/Y in hexadecimal form (4 digits) ; (if Carry is set, a radix prefix '$' is printed as well) %asm {{ stx c64.SCRATCH_ZP1 tya jsr print_byte_hex lda c64.SCRATCH_ZP1 clc jmp print_byte_hex }} } sub print_word_decimal0 (dataword: XY) -> (?) { ; ---- print the (unsigned) word in X/Y in decimal form, with left padding 0s (5 positions total) %asm {{ jsr word2decimal lda word2decimal_output jsr c64.CHROUT lda word2decimal_output+1 jsr c64.CHROUT lda word2decimal_output+2 jsr c64.CHROUT lda word2decimal_output+3 jsr c64.CHROUT lda word2decimal_output+4 jmp c64.CHROUT }} } sub print_word_decimal (dataword: XY) -> (A?, X?, Y?) { ; ---- print the word in X/Y in decimal form, without left padding 0s %asm {{ jsr word2decimal ldy #0 lda word2decimal_output cmp #'0' bne _pr_decimal iny lda word2decimal_output+1 cmp #'0' bne _pr_decimal iny lda word2decimal_output+2 cmp #'0' bne _pr_decimal iny lda word2decimal_output+3 cmp #'0' bne _pr_decimal iny _pr_decimal lda word2decimal_output,y jsr c64.CHROUT iny cpy #5 bcc _pr_decimal rts }} } sub input_chars (buffer: AX) -> (A?, Y) { ; ---- Input a string (max. 80 chars) from the keyboard. ; It assumes the keyboard is selected as I/O channel!! %asm {{ sta c64.SCRATCH_ZP1 stx c64.SCRATCH_ZP2 ldy #0 ; char counter = 0 - jsr c64.CHRIN cmp #$0d ; return (ascii 13) pressed? beq + ; yes, end. sta (c64.SCRATCH_ZP1),y ; else store char in buffer iny bne - + lda #0 sta (c64.SCRATCH_ZP1),y ; finish string with 0 byte rts }} } } ; ---- end block c64scr ;sub memcopy_basic () -> (?) { ; ; ---- copy a memory block by using a BASIC ROM routine ; ; it calls a function from the basic interpreter, so: ; ; - BASIC ROM must be banked in ; ; - the source block must be readable (so no RAM hidden under BASIC, Kernal, or I/O) ; ; - the target block must be writable (so no RAM hidden under I/O) ; ; higher addresses are copied first, so: ; ; - moving data to higher addresses works even if areas overlap ; ; - moving data to lower addresses only works if areas do not overlap ; %asm {{ ; lda #src_start ; sta $5f ; stx $60 ; lda #src_end ; sta $5a ; stx $5b ; lda #<(target_start + src_end - src_start) ; ldx #>(target_start + src_end - src_start) ; sta $58 ; stx $59 ; jmp $a3bf ; } ;} ; macro version of the above memcopy_basic routine: ; MACRO PARAMS src_start, src_end, target_start ; lda #src_start ; sta $5f ; stx $60 ; lda #src_end ; sta $5a ; stx $5b ; lda #<(target_start + src_end - src_start) ; ldx #>(target_start + src_end - src_start) ; sta $58 ; stx $59 ; jsr $a3bf