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C02/include/run6502.a02
2020-10-11 14:45:01 -04:00

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;run6502 program initialization code for c02 programs
;System Specific ASCII Key Mappings
DELKEY EQU $08 ;Delete/Backspace Key (Backspace)
ESCKEY EQU $18 ;Escape/Stop Key (Control-X)
RTNKEY EQU $0A ;Return/Enter Key (Line Feed)
;Zero Page Locations
SRCPTR EQU $30 ;Source String Pointer (stdio.a02)
SRCLO EQU $30
SRCHI EQU $31
DSTPTR EQU $32 ;Destination String Pointer (string.a02)
DSTLO EQU $32
DSTHI EQU $33
BFRPTR EQU $34 ;Work Buffer Pointer
BFRLO EQU $34
BFRHI EQU $35
BLKPTR EQU $36 ;Block Segment Pointer (block.a02)
BLKLO EQU $36
BLKHI EQU $37
STKLO EQU $38 ;Stack Pointer (stack.a02)
STKHI EQU $39
RDSEED EQU $3E ;Pseudo-RANDOM Seed
RANDOM EQU $3F ;Pseudo-RANDOM Number Storage
TEMP0 EQU $40 ;Temporary Storage
TEMP1 EQU $41
TEMP2 EQU $42
TEMP3 EQU $43
BLKSLO EQU $46 ;Block Start Address
BLKSHI EQU $47
BLKELO EQU $48 ;Block End Address
BLKEHI EQU $49
BLKLEN EQU $4A ;Block Segment Length
STKSLO EQU $4C ;Stack Start Address
STKSHI EQU $4D
STKELO EQU $4E ;Stack End Address
STKEHI EQU $4F
SYSBFP EQU $50 ;Position in System Buffer
SYSBFL EQU 128 ;System Buffer Size (Max String Size)
SYSBFR EQU $0200 ;System Buffer
;Memory Mapped I/O
_KBHIT EQU $FFF0 ;Is a Key Pressed
_GETCH EQU $FFF1 ;Read Keyboard (Blocking)
ORG $0400 ;START at RAM midpoint
START: JMP MAIN ;Execute Program
;Read Character from Console
GETKEY EQU $FFE0 ;Emulator CHRIN Routine
;Poll Character from Keyboard
POLKEY: BRK ;Exit Emulator
;Wait for Character from Console
GETCHR: JSR GETKEY ;Read Character from STDIN
CMP #$FF ;If EOF
BNE GETCHX
LDA #ESCKEY ; Set to Escape Character
GETCHX: ORA 0 ;Set Zero Flag
RTS
;Delete Previous Character
DELCHR: LDA #$08 ;Load Backspace into Accumulator
JSR PUTCHR ; and Print it
LDA #$20 ;Load Space into Accumulater
JSR PUTCHR ; and Print it
LDA #$08 ;Load Backspace into Accumulator
JMP PUTCHR ; and Print it
;Advance Character to Next line
NEWLIN: LDA #RTNKEY ;Load Line Feed into Accumulater
JMP PUTCHR ; and Print it
;Print Character to Console
PUTCHR EQU $FFE3 ;Emulator CHROUT Routine
EXIT EQU $FFEC ;Emulator SHUTDN Routine
FSCMD EQU $FFE6 ;run6502 File System Command Routine
INCLUDE "../include/prbyte.a02" ;PRBYTE and PRHEX routines
INCLUDE "../include/putstr.a02" ;PUTSTR routine