******************************** * * * 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 * * 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 ALTCHAR EQU $C01E ;CHARACTER SET STATUS RD80VID EQU $C01F ;<=128->40COL, >128->80COL 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 * * 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 * * * ******************************** CPIN 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 * * * ******************************** SET1 MAC LDA #1 STA ]1 <<< SET0 MAC LDA #0 STA ]1 <<< SET23 MAC LDA #23 STA ]1 <<< ******************************** * * * STANDARD ASSEM LANG * * BACKWARDS COPY OF 1 BYTE * * A IS DESTROYED * * ]1 DESTINATION * * ]2 SOURCE * * * ******************************** COPY_B MAC LDA ]2 STA ]1 <<< ******************************** * * * MAIN PROGRAM * * * ******************************** MAIN CLD ;CLEAR DECIMAL FLG, AVOID CRASH SET0 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 CPIN 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 CARD IS 40-COL :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 COPY_B SCRNLINE;#1 ;INIT SCREEN LINE NUMBER COPY_B 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 COPY_B LINEIDX;#1 ;RESET TO BEGINNING OF LINE ;COPY_B OURCH;#0 JSR CROUT ;LINE DOWN & SCROLL IF NEEDED 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 SET1 SCRNLINE ;ADVANCE ONE PAGE, STORE 1 JMP :ENDLOOP ;PROCESSED SPACE SO DONE :CHKCR CMP #CR_HIBIT ;CHECK FOR CARRIAGE RETURN BNE :CHKQUIT SET23 SCRNLINE JMP :ENDLOOP :CHKQUIT CMP #"Q" ;USER WANTS TO QUIT BEQ :QUITTING ;NO RECOGNIZED INPUT CMP #"q" BEQ :QUITTING JMP :LOOP :QUITTING SET1 USRQUIT :ENDLOOP JSR ERASEBAR POPY DO TRACE PUTS EXSTATB FIN RTS ******************************** * * * ERASE STATUS BAR * * * ******************************** ERASEBAR DO TRACE PUTS ENERASEB FIN PUSHY SET0 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 SET0 OURCH ;RESET CURSOR TO BEG OF LINE POPY DO TRACE PUTS EXERASEB FIN 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=" 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