prodos-more/more.merlin.s
Bill Chatfield d469708c37 Rebase
2024-10-17 23:37:54 -04:00

998 lines
29 KiB
ArmAsm

********************************
* *
* MORE - UN*X MORE COMMAND *
* ASSEMBLES WITH MERLIN *
* *
********************************
* Memory Map
*
* $0000 - $00FF Zero Page
* $0100 - $01FF Stack
* $0200 - $03FF Mostly Free, Input Buffer, Interrupt Vectors
* $0400 - $07FF Lo-res/Text Page1
* $0800 - $0BFF Lo-res/Text Page2 (BASIC programs load here)
* $0C00 - $1FFF Free
* $2000 - $3FFF Hi-res Page1
* $4000 - $5FFF Hi-res Page2
* $6000 - $95FF Free
* $9600 - $BFFF DOS3.3 and Buffers
* $C000 - $CFFF Soft Switches, Expansion Card I/O and ROM
* $D000 - $F7FF BASIC ROM (can be bankswitched later models)
* $F800 - $FFFF Machine Language Monitor ROM (also can be bankswitched)
*
* Branching - I can never remember this scheisse
*
* CMP,CPX,CPY ->
* Condition N Z C
* Register < Memory 1 0 0
* Register = Memory 0 1 1
* Register > Memory 0 0 1
*
* BPL - BRANCH PLUS (N=0) NOT NEGATIVE
* BMI - BRANCH MINUS (N=1) NEGATIVE
* BEQ - BRANCH EQUAL (Z=1) ZERO FLAG SET
* BNE - BRANCH NOT EQUAL (Z=0) ZERO FLAG NOT SET
* BCC - BRANCH CARRY CLEAR (C=0)
* BCS - BRANCH CARRY SET (C=1)
* BVC - BRANCH OVERVLOW CLEAR (V=0)
* BVS - BRANCH OVERFLOW SET (V=1)
DSK MORE ;WRITE ASSEMBLED FILE TO DISK
TYP $06 ;$FF=SYSTEM, $06=BINARY
ORG $2000 ;ASSEMBLE START ADDRESS
*
* SYSTEM VARIABLES
*
PTR EQU 06 ;ONLY FREE 0-PAGE LOCATION
CH EQU $24 ;40-COL HORZ CURS POSITION
CV EQU $25 ;40-COL VERT CURS POSITION
PROMPT EQU $33 ;PROMPT CHARACTER
ZP_A1L EQU $3C ;MONITOR GENERAL PURPOSE
ZP_A1H EQU $3D ;MONITOR GENERAL PURPOSE
IN EQU $200 ;256-CHAR INPUT BUF
*
* SLOT 3 SCRATCHPAD RAM - TEXT PAGE 0 SCREEN HOLE
* http://yesterbits.com/media/books/apple/heiserman-1983-intermediate-level-apple-ii-handbook.pdf
*
OURCH EQU $057B ;80-COL HORIZ CURSOR POSITION
OURCV EQU $05FB ;VERTICAL CURSOR POSITION
*
* SUBROUTINES IN MONITOR ROM: $F800 - $FFFF
*
CR EQU $FC62 ;CURSOR TO BEG OF NEXT LINE
RDKEY EQU $FD0C ;READS A CHARACTER
GETLN EQU $FD6A ;READS A LINE, WITH PROMPT($33)
GETLN1 EQU $FD6F ;READS A LINE, NO PROMPT
CROUT EQU $FD8E
COUT EQU $FDED
PRBYTE EQU $FDDA
*
* SUBROUTINES IN BASIC.SYSTEM ROM:
*
GETBUFR EQU $BEF5 ;BCC=OKAY & A=HIBYTE OF BUF
;BCS=FAIL & A=ERRCODE
;X & Y ARE DESTROYED
FREEBUFR EQU $BEF8 ;FREE BUFFER
*
* PRODOS ENTRY POINT
*
PRODOS_MLI EQU $BF00 ;MACHINE LANG IFACE (MLI)
*
* MEMORY MAPPED I/O: $C000 - $CFFF
*
KBD EQU $C000 ;KEYBOARD DATA AND STROBE
CXROMOFF EQU $C006 ;SELECT SLOT ROMS
CXROMON EQU $C007 ;SELECT INTERNAL ROM
KBDSTRB EQU $C010 ;CLEAR KEYBOARD STROBE
MIXED EQU $C01B ;R7=1 MIXED, R7=0 FULL GR
PAGE2 EQU $C01C ;R7-1 PAGE ACTIVE (OR AUX)
ALTCHAR EQU $C01E ;CHARACTER SET STATUS
RD80VID EQU $C01F ;<=128->40COL, >128->80COL
PAGE2OFF EQU $C054 ;SEL PG1 (RW)
PAGE2ON EQU $C055 ;SEL PG2 (RW)
INVERT EQU $CEDD ;INVERT CHARACTER ON SCREEN
PICK EQU $CF01 ;PICK CHARACTER OFF SCREEN
*
* PRODOS COMMAND CODES
*
GET_PREFIX EQU $C7
OPEN EQU $C8
READ EQU $CA
CLOSE EQU $CC
*
* PRODOS MLI PARAMETER COUNTS
*
GETPRFXPARMCNT EQU 1
OPENPARMCNT EQU 3
READPARMCNT EQU 4
CLOSEPARMCNT EQU 1
*
* ASCII
*
CR_CHAR EQU $0D ;ASCII CARRIAGE RETURN
CR_HIBIT EQU $8D ;CARRIAGE RET WITH HIGH BIT SET
RIGHT_ARROW EQU $15
RIGHT_HIBIT EQU $95
LEFT_ARROW EQU $08
LEFT_HIBIT EQU $88
*
* CONSTANTS
*
EOFERR EQU $4C ;ERROR CODE FOR END-OF-FILE
MAXERCDE EQU $5A ;LARGEST ERROR CODE
BUFSIZE EQU $00FF
SCR_HGHT EQU 24 ;SCREEN HEIGHT
*
* DEBUGGING
*
TRACE EQU 0
********************************
* *
* PUSH Y ONTO THE STACK *
* DESTROYS A *
* *
********************************
PUSHY MAC
TYA
PHA
<<<
********************************
* *
* POP Y FROM THE STACK *
* DESTROYS A *
* *
********************************
POPY MAC
PLA
TAY
<<<
********************************
* *
* COPY IN BUF TO STRING *
* *
* X CONTAINS LENGTH OF "IN" *
* ]1 IS DEST STRING (LEN BYT) *
* A IS DESTROYED *
* *
********************************
COPYIN MAC
PUSHY ;SAVE Y
STX ]1 ;COPY LENGTH TO FIRST BYTE OF ]1
LDY #0 ;INIT Y TO ZERO
LOOP CPY ]1 ;COMPARE Y WITH LENGTH BYTE
BEQ ENDLOOP ;DONE IF LENGTH IS REACHED
LDA IN,Y ;LOAD IN[Y] INTO ACCUMULATOR
CMP #CR_CHAR ;COMPARE WITH CARRIAGE RETURN
BEQ ENDLOOP ;STOP AT CARRIAGE RETURN
INY ;DEST STR IS 1 AHEAD OF IN BUF
STA ]1,Y ;COPY CHAR TO DEST STR ]1
JMP LOOP ;LOOP TO NEXT CHAR
ENDLOOP POPY ;RESTORE Y
<<<
********************************
* *
* WRITES A LENGTH PREFIXED *
* STRING TO THE SCREEN *
* A IS DESTROYED *
* *
********************************
PUTS MAC
PUSHY
LDY #0 ;INIT LOOP INDEX
LOOP CPY ]1 ;HAS STR LENGTH BEEN REACHED
BEQ ENDLOOP ;IF SO THEN FINISH
INY ;MOVE TO INDEX OF NEXT CHAR
LDA ]1,Y ;GET THE CHAR TO BE WRITTEN
JSR COUT ;WRITE THE CHARACTER
JMP LOOP ;LOOP
ENDLOOP POPY
<<<
********************************
* *
* SET TO #1 (IMMEDIATE 1) *
* ]1 DESTINATION *
* A IS DESTROYED *
* *
********************************
STORE1 MAC
LDA #1
STA ]1
<<<
STORE0 MAC
LDA #0
STA ]1
<<<
STORE23 MAC
LDA #23
STA ]1
<<<
********************************
* *
* STANDARD ASSEM LANG *
* BACKWARDS COPY OF 1 BYTE *
* A IS DESTROYED *
* ]1 DESTINATION *
* ]2 SOURCE *
* *
********************************
COPYB MAC
LDA ]2
STA ]1
<<<
********************************
* *
* MAIN PROGRAM *
* *
********************************
MAIN CLD ;CLEAR DECIMAL FLG, AVOID CRASH
STORE0 USRQUIT ;INITIALIZE TO "NO"
JSR GET_SCRN_WDTH
*
* GET PREFIX TO SEE IF IT IS SET
*
JSR PRODOS_MLI
DB GET_PREFIX
DA GETPRFXPARMS
BEQ :CHKPREFIX
JSR GETPRFXERR
JMP :END
:CHKPREFIX LDA PREFIX
CMP #0
BNE :GETFILE
JSR CROUT
PUTS WARNING
PUTS NOPREFIXMSG
JSR CROUT
JSR CROUT
*
* GET FILE NAME
*
:GETFILE PUTS INFOLINE
JSR CROUT
:ASKFILE PUTS FILEPROMPT
JSR GETLN1 ;LENGTH IN X, CR AT END
CPX #0 ;IS THE LENGTH ZERO?
BNE :CONT0 ;USER JUST PRESSED RETURN
JMP :END
:CONT0 CPX #1
BNE :CONT1
LDA #"?"
CMP IN
BNE :CONT1
JSR HELPINFO
JMP :ASKFILE
:CONT1 COPYIN FILENAME ;COPY "IN" BUF TO FILENAME
DO TRACE
JSR PRSTRBYTES
JSR GETLN
FIN
*
* GET FILE I/O BUFFER FOR OPEN CALL
*
LDA #4 ;FOUR 256 BYTE PAGES = 1KB
JSR GETBUFR ;GET BUF FROM BASIC.SYSTEM
BCC :CONT2 ;CARRY CLEAR MEANS NO ERROR
JSR OBUFERR
JMP :END
:CONT2 STA OBUFADDR+1 ;GETBUFR RETURNS HIBYTE IN A
LDA #0 ;PREPARE
STA OBUFADDR ;LOBYTE IS 0 B/C ADDR OF PAGE
*
* OPEN FILE
*
JSR PRODOS_MLI
DB OPEN
DA OPENPARMS
BEQ :CONT3
JSR OPENERR
JSR FREEBUFR ;CLEAN UP BEFORE TRY AGAIN
JMP :ASKFILE
*
* COPY FILE NUMBER FROM OPEN PARAMETERS TO READ AND CLOSE
*
:CONT3 LDA OPENFNUM
STA READFNUM
STA CLOSFNUM
*
* GET BUFFER FOR READ OPERATION FROM BASIC.SYSTEM
*
LDA #1 ;ONE 256 BYTE BUFFER
JSR GETBUFR ;CALL BASIC.SYSTEM SUB
BCC :CONT4
JSR RBUFERR ;CARRY SET MEANS ERROR
JMP :CLOSFILE
:CONT4 STA RBADDR+1 ;STORE HI-BYTE
STA ZP_A1H ;FOR 0-PAGE INDIRECTION
LDA #0 ;0 FOR LO-BYTE
STA RBADDR ;STORE IT
STA ZP_A1L ;AGAIN, FOR 0-PAGE INDIRECTION
*
* PRINT THE FILE
*
JSR VIEWFILE
*
* CLEANUP
*
JSR FREEBUFR ;FREE READ BUFFER
*
* Close file
*
:CLOSFILE JSR PRODOS_MLI ;CLOSE THE FILE
DB CLOSE
DA CLOSEPARMS
BEQ :FREEOBUF
JSR CLOSERR
:FREEOBUF JSR FREEBUFR ;FREE OPEN I/O BUFFER
:END NOP
RTS
********************************
* *
* END OF MAIN - PROGRAM EXIT *
* *
********************************
********************************
* *
* DETERMINE IF SCREEN IS IN *
* 40 COL OR 80 COL MODE *
* *
********************************
GET_SCRN_WDTH LDA #%10000000 ;USE ALTCHARSET STATUS TO
BIT ALTCHAR ;SEE IF 80-COL CARD TURNED ON
BMI :CARD_ACTIVE ;BIT 7 ON = NEG & CARD ACTIVE
JMP :FORTY_COLUMNS ;INACTIVE = DEFLT 40-COL MODE
:CARD_ACTIVE LDA #%10000000 ;SEE IF CARD IS IN 40/80 MODE
BIT RD80VID ;BIT 7 OFF = 0 OR >0 & 40-COL
BMI :EIGHTY_COLUMNS ;BIT 7 ON = NEG & 80-COL MODE
:FORTY_COLUMNS LDA #40
STA SCR_WDTH
JMP :END
:EIGHTY_COLUMNS LDA #80
STA SCR_WDTH
:END
DO TRACE
LDA ALTCHAR
JSR PRBYTE
JSR CROUT
LDA RD80VID
JSR PRBYTE
JSR CROUT
PUTS SCR_WDTH_TXT
LDA SCR_WDTH
JSR PRBYTE
JSR CROUT
FIN
RTS
********************************
* *
* PROGRAM INFO AND HELP *
* *
********************************
HELPINFO JSR CROUT
PUTS INFO0
JSR CROUT
PUTS INFO1
JSR CROUT
PUTS INFO2
JSR CROUT
PUTS INFO3
JSR CROUT
PUTS INFO4
JSR CROUT
JSR CROUT
RTS
********************************
* *
* HANDLE ERROR WHEN GETTING *
* PREFIX *
* *
********************************
GETPRFXERR STA ERRCODE
PUTS GETPRFXERRMSG
LDA #":"
JSR COUT
LDA ERRCODE
JSR ERRPROC
RTS
********************************
* *
* HANDLE ERROR WHEN OPENING *
* FILE *
* *
********************************
OPENERR STA ERRCODE
PUTS OERRMSG
PUTS FILENAME
LDA #":"
JSR COUT
LDA ERRCODE
JSR ERRPROC
RTS
********************************
* *
* HANDLE ERROR WHEN CLOSING *
* FILE *
* *
********************************
CLOSERR STA ERRCODE
PUTS CERRMSG
PUTS FILENAME
LDA #"'"
JSR COUT
LDA #":"
JSR COUT
LDA ERRCODE
JSR ERRPROC
RTS
********************************
* *
* HANDLE ERROR WHEN REQUESTING *
* READ BUFFER *
* *
********************************
RBUFERR STA ERRCODE
PUTS RBERRMSG
LDA #":"
JSR COUT
LDA ERRCODE
JSR ERRPROC
RTS
********************************
* *
* HANDLE ERROR WHEN REQUESTING *
* READ BUFFER *
* *
********************************
OBUFERR STA ERRCODE
PUTS OBERRMSG
LDA #":"
JSR COUT
LDA ERRCODE
JSR ERRPROC
RTS
********************************
* *
* PRINT "IN" BUFFER *
* *
********************************
PRINT_IN
PUSHY
LDA #"X"
JSR COUT
LDA #"="
JSR COUT
TXA
JSR PRBYTE
JSR CROUT
LDY #0
:LOOP CPY #255
BEQ :ENDLOOP
LDA IN,Y
JSR PRBYTE
LDA #" "
JSR COUT
INY
JMP :LOOP
:ENDLOOP JSR CROUT
POPY
RTS
********************************
* *
* PRINT STRING BYTES *
* *
********************************
PRSTRBYTES PUSHY
LDY #0
:LOOP CPY #255
BEQ :ENDLOOP
LDA FILENAME,Y
JSR PRBYTE
LDA #" "
JSR COUT
INY
JMP :LOOP
:ENDLOOP JSR CROUT
POPY
RTS
********************************
* *
* VIEW FILE SUB *
* *
********************************
VIEWFILE
DO TRACE
PUTS ENVIEW
FIN
COPYB SCRNLINE;#1 ;INIT SCREEN LINE NUMBER
COPYB LINEIDX;#1 ;POSITION IN LINE
:LOOP JSR PRODOS_MLI ;CALL PRODOS TO READ FILE
DB READ ;SPECIFY PRODOS READ COMMAND
DA READPARMS ;READ PARAMETERS
BNE :READERR
JSR WRITEBUF ;WRITE TO SCREEN WHAT WAS READ
LDA #1 ;PREPARE FOR NEXT OP
CMP USRQUIT ;IF USER WANTS TO QUIT, THEN
BEQ :ENDLOOP ;EXIT THE LOOP
JMP :LOOP ;ELSE, GET THE NEXT BUFFER
:READERR JSR ERRPROC
:ENDLOOP NOP
RTS
********************************
* *
* WRITE BUFFER TO SCREEN *
* *
********************************
WRITEBUF PUSHY
LDY #0 ;INIT CHAR COUNTER VARIABLE
:LOOP CPY READCNT ;COMPARE TO MAX CHARS
BEQ :ENDLOOP
LDA (ZP_A1L),Y ;GET CHAR FROM BUFFER
ORA #%10000000 ;TURN ON HIGH BIT FOR PRINTING
JSR WRITECHAR ;COUT PRESERVES ACCUM
*
* CHECK AT END OF PAGE
*
LDA SCRNLINE ;CURSOR VERTICAL SCREEN LINE
CMP #SCR_HGHT ;AT BOTTOM OF SCREEN?
BNE :CONT ;NO? THEN NEXT CHAR
JSR STATBAR ;YES? THEN SHOW THE STATUS BAR
LDA #1 ;SETUP FOR NEXT LINE
CMP USRQUIT ;DID USER ASK TO QUIT
BEQ :ENDLOOP ;YES? THEN END SUB
:CONT INY ;STATBAR HAS ADJUSTED LINENUM
JMP :LOOP
:ENDLOOP NOP
POPY
DO TRACE
PUTS EXWRITEBUF
FIN
RTS
********************************
* *
* WRITE CHAR TO SCREEN *
* CLIPS TO SCREEN WIDTH *
* *
********************************
WRITECHAR STA CHAR ;DON'T LOOSE THE CHARACTER
CMP #CR_HIBIT ;COMPARE TO CARRIAGE RETURN
BNE :NOT_EOL ;IF NOT END OF LINE, PRINT
JSR DOWN1LINE
JMP :ENDSUB ;NOTHING MORE TO DO FOR EOL
:NOT_EOL LDA LINEIDX ;GET CURSOR HORIZ COL
CMP SCR_WDTH ;COMPARE WITH SCREEN WIDTH
BPL :FORWARD ;DON'T PRINT IF OFF SCREEN
LDA CHAR ;ON SCREEN, SO PRINT IT
JSR COUT
:FORWARD INC LINEIDX
:ENDSUB RTS
********************************
* *
* GO TO BEGINNING OF NEXT LINE *
* *
********************************
DOWN1LINE INC SCRNLINE ;KEEP TRACK OF LINE NUMBER
STORE1 LINEIDX ;RESET TO BEGINNING OF LINE
;COPYB OURCH;#0
JSR CROUT ;LINE DOWN & SCROLL IF NEEDED
RTS
********************************
* *
* WRITE CHAR TO PAGE2 *
* CLIPS TO SCREEN WIDTH *
* *
********************************
WRITECHAR2
RTS
********************************
* *
* PRINT ASCII IN HEX *
* *
********************************
PRASCII PHA
LDA #"["
JSR COUT
PLA
JSR PRBYTE
LDA #"]"
JSR COUT
LDA #" "
JSR COUT
RTS
********************************
* *
* DO THE STATUS BAR *
* *
********************************
STATBAR
DO TRACE
PUTS ENSTATB
FIN
PUSHY
PUTS BAR
:LOOP JSR RDKEY ;GET A KEY FROM THE USER
CMP #" " ;CHECK IF SPACE ENTERED
BNE :CHKCR ;IF NOT FORWARD TO NEXT CHECK
STORE1 SCRNLINE ;ADVANCE ONE PAGE, STORE 1
JMP :ENDLOOP ;PROCESSED SPACE SO DONE
:CHKCR CMP #CR_HIBIT ;CHECK FOR CARRIAGE RETURN
BNE :CHKQUIT
STORE23 SCRNLINE
JMP :ENDLOOP
:CHKQUIT CMP #"Q" ;USER WANTS TO QUIT
BEQ :QUITTING ;NO RECOGNIZED INPUT
CMP #"q"
BEQ :QUITTING
JMP :LOOP
:QUITTING STORE1 USRQUIT
:ENDLOOP JSR ERASEBAR
POPY
DO TRACE
PUTS EXSTATB
FIN
RTS
********************************
* *
* ERASE STATUS BAR *
* *
********************************
ERASEBAR
DO TRACE
PUTS ENERASEB
FIN
PUSHY
STORE0 OURCH ;RESET CURSOR TO BEG OF LINE
LDY #0 ;INIT COUNTER FOR SPACES
:LOOP CPY BAR ;FIRST BYTE IS LENGTH
BEQ :ENDLOOP ;IF Y=LEN THEN DONE
LDA #" " ;LOAD SPACE
JSR COUT ;WRITE TO SCREEN
INY ;MAKE PROGRESS
JMP :LOOP ;LOOP TO NEXT CHAR
:ENDLOOP STORE0 OURCH ;RESET CURSOR TO BEG OF LINE
POPY
DO TRACE
PUTS EXERASEB
FIN
RTS
********************************
* *
* PAGE 2 ON *
* *
********************************
PAGE_RIGHT STA PAGE2ON
RTS
********************************
* *
* ERROR HANDLER *
* INPUT PARAM: A HOLDS ERRCODE *
* *
********************************
ERRPROC
STA ERRCODE
CMP #0
BNE :EEOF
JMP :END
:EEOF CMP #EOFERR
BNE :E01
JMP :END
:E01 CMP #1
BNE :E04
PUTS E01MSG
JMP :END
:E04 CMP #4
BNE :E25
PUTS E04MSG
JMP :END
:E25 CMP #$25
BNE :E27
PUTS E25MSG
JMP :END
:E27 CMP #$27
BNE :E28
PUTS E27MSG
JMP :END
:E28 CMP #$28
BNE :E2B
PUTS E28MSG
JMP :END
:E2B CMP #$2B
BNE :E2E
PUTS E2BMSG
JMP :END
:E2E CMP #$2E
BNE :E40
PUTS E2EMSG
JMP :END
:E40 CMP #$40
BNE :E42
PUTS E40MSG
JMP :END
:E42 CMP #$42
BNE :E43
PUTS E42MSG
JMP :END
:E43 CMP #$43
BNE :E44
PUTS E43MSG
JMP :END
:E44 CMP #$44
BNE :E45
PUTS E44MSG
JMP :END
:E45 CMP #$45
BNE :E46
PUTS E45MSG
JMP :END
:E46 CMP #$46
BNE :E47
PUTS E46MSG
JMP :END
:E47 CMP #$47
BNE :E48
PUTS E47MSG
JMP :END
:E48 CMP #$48
BNE :E49
PUTS E48MSG
JMP :END
:E49 CMP #$49
BNE :E4A
PUTS E49MSG
JMP :END
:E4A CMP #$4A
BNE :E4B
PUTS E4AMSG
JMP :END
:E4B CMP #$4B
BNE :E4C
PUTS E4BMSG
JMP :END
:E4C CMP #$4C
BNE :E4D
PUTS E4CMSG
JMP :END
:E4D CMP #$4D
BNE :E4E
PUTS E4DMSG
JMP :END
:E4E CMP #$4E
BNE :E50
PUTS E4EMSG
JMP :END
:E50 CMP #$50
BNE :E51
PUTS E50MSG
JMP :END
:E51 CMP #$51
BNE :E52
PUTS E51MSG
JMP :END
:E52 CMP #$52
BNE :E53
PUTS E52MSG
JMP :END
:E53 CMP #$53
BNE :E55
PUTS E53MSG
JMP :END
:E55 CMP #$55
BNE :E56
PUTS E55MSG
JMP :END
:E56 CMP #$56
BNE :E57
PUTS E56MSG
JMP :END
:E57 CMP #$57
BNE :E5A
PUTS E57MSG
JMP :END
:E5A CMP #$5A
BNE :E_UNK
PUTS E5AMSG
JMP :END
:E_UNK PUTS E_UNK_MSG
LDA #":"
JSR COUT
LDA ERRCODE
JSR PRBYTE
:END JSR CROUT
RTS
********************************
* *
* DATA DIVISION HAHA *
* *
********************************
INFOLINE STR "ENTER [?] FOR PROGRAM INFO AND HELP"
INFO0 STR "MORE - PAGES THROUGH TEXT FILE"
INFO1 STR "COPYRIGHT (C) 2024 BILL CHATFIELD"
INFO2 STR "DISTRIBUTED UNDER THE GPL VERSION 3"
INFO3 STR "https://github.com/gungwald/prodos-more"
INFO4 STR "PRESS RETURN TO QUIT"
FILEPROMPT STR "FILE:"
ERRTXT STR "ERROR:"
FILENAME DS $FF
PREFIX DS 64
ERRCODE DS 1
SCRNLINE DS 1
LINEIDX DS 1
CHAR DS 1
BAR STR '[RET] LINE [SPC] PAGE [Q]UIT'
USRQUIT DS 1
BUFCHAR DS 1
USRCHAR DS 1
SCR_WDTH DS 1
SCR_WDTH_TXT STR "SCREEN WIDTH="
TEXTPAGE DS 1
PREFIXMSG STR "THE PREFIX IS "
WARNING STR 'WARNING'
NOPREFIXMSG STR ": NO PREFIX IS SET. YOU MUST ENTER THE FULL PATH TO THE FILE."
GETPRFXERRMSG STR "CANNOT GET PREFIX"
OERRMSG STR "CANNOT OPEN "
CERRMSG STR "CANNOT CLOSE "
RBERRMSG STR "CANNOT CREATE READ BUFFER"
OBERRMSG STR "CANNOT CREATE FILE BUFFER"
E00MSG STR "NO ERROR"
E01MSG STR "BAD SYSTEM CALL NUMBER"
E04MSG STR "BAD SYSTEM CALL PARAMETER COUNT"
E25MSG STR "INTERRUPT TABLE FULL"
E27MSG STR "I/O ERROR"
E28MSG STR "NO DEVICE CONNECTED"
E2BMSG STR "DISK WRITE PROTECTED"
E2EMSG STR "DISK SWITCHED"
E40MSG STR "INVALID PATHNAME"
E42MSG STR "MAXIMUM NUMBER OF FILES OPEN"
E43MSG STR "INVALID REFERENCE NUMBER"
E44MSG STR "DIRECTORY NOT FOUND"
E45MSG STR "VOLUME NOT FOUND"
E46MSG STR "FILE NOT FOUND"
E47MSG STR "DUPLICATE FILENAME"
E48MSG STR "VOLUME FULL"
E49MSG STR "VOLUME DIRECTORY FULL"
E4AMSG STR "INCOMPATIBLE FILE FORMAT OR PRODOS DIRECTORY"
E4BMSG STR "UNSUPPORTED STORAGE TYPE"
E4CMSG STR "END OF FILE ENCOUNTERED"
E4DMSG STR "POSITION OUT OF RANGE"
E4EMSG STR "FILE ACCESS ERROR OR FILE LOCKED"
E50MSG STR "FILE IS OPEN"
E51MSG STR "DIRECTORY STRUCTURE DAMAGED"
E52MSG STR "NOT A PRODOS VOLUME"
E53MSG STR "INVALID SYSTEM CALL PARAMETER"
E55MSG STR "VOLUME CONTROL BLOCK TABLE FULL"
E56MSG STR "BAD BUFFER ADDRESS"
E57MSG STR "DUPLICATE VOLUME"
E5AMSG STR "FILE STRUCTURE DAMAGED"
E_UNK_MSG STR "UNKNOWN ERROR CODE"
ENVIEW STR 'ENTERING VIEWFILE'
EXVIEW STR 'EXITING VIEWFILE'
EXWRITEBUF STR 'EXITING WRITEBUF'
ENSTATB STR 'ENTERING STATUSBAR'
EXSTATB STR 'EXITING STATUSBAR'
ENERASEB STR 'ENTERING ERASEBAR'
EXERASEB STR 'EXITING ERASEBAR'
*
* GET_PREFIX PARAMETERS
*
GETPRFXPARMS DB #GETPRFXPARMCNT
PREFIXADDR DA PREFIX
*
* OPEN PARAMETERS
*
OPENPARMS DB #OPENPARMCNT
DA FILENAME
OBUFADDR DS 2
OPENFNUM DS 1
*
* READ PARAMETERS
*
READPARMS DB #READPARMCNT
READFNUM DS 1
RBADDR DS 2
REQCNT DW BUFSIZE
READCNT DS 2
*
* CLOSE PARAMETERS
*
CLOSEPARMS DB #CLOSEPARMCNT
CLOSFNUM DS 1
*
* BUFFERS
*
* CONSUME ALL BYTES UP TO THE NEXT PAGE BOUNDRY
*FILLER DS \,$00
* MUST START ON PAGE BOUNDRY
*OPENBUF DS 1024
*READBUF DS BUFSIZE