1
0
mirror of https://github.com/RevCurtisP/C02.git synced 2024-11-22 16:34:15 +00:00
C02/include/py65.a02

102 lines
3.0 KiB
Plaintext
Raw Normal View History

2018-01-28 18:30:49 +00:00
; py65mon program initialization code for c02 programs
;System Specific ASCII Key Mappings
DELKEY EQU $08 ;Delete/Backspace Key (Backspace)
2018-01-28 18:30:49 +00:00
ESCKEY EQU $1B ;Escape/Stop Key (Escape)
RTNKEY EQU $0D ;Return/Enter Key (Carriage Return)
;Zero Page Locations
SRCLO EQU $30 ;Source String Pointer (stdio.a02)
SRCHI EQU $31
DSTLO EQU $32 ;Destination String Pointer (string.a02)
DSTHI EQU $33
BLKLO EQU $34 ;Block Segment Pointer (block.a02)
BLKHI EQU $35
2018-07-25 23:00:46 +00:00
STKLO EQU $36 ;Stack Pointer (stack.a02)
STKHI EQU $37
2018-01-28 18:30:49 +00:00
RDSEED EQU $3E ;Pseudo-RANDOM Seed
RANDOM EQU $3F ;Pseudo-RANDOM Number Storage
2018-01-28 18:30:49 +00:00
TEMP0 EQU $40 ;Temporary Storage
TEMP1 EQU $41
TEMP2 EQU $42
TEMP3 EQU $43
2018-07-25 23:00:46 +00:00
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
2018-01-28 18:30:49 +00:00
;Memory Mapped I/O
PUTCON EQU $F001 ;Write Character to Console
GETCON EQU $F004 ;Read Character from Console
2018-01-28 18:30:49 +00:00
ORG $0200 ;START Directly Above Stack
START: JMP MAIN ;Execute Program
;Poll Character from Keyboard
PLKEY: INC RDSEED ;Cycle the RANDOM Seed (if not provided by system)
LDA GETCON ;Read Character from Console
2018-08-14 18:14:32 +00:00
CMP #$E0
BEQ PLKEYX ;If Not E0 Extended Key
ORA #$00 ; Set Status Flags
RTS ; and Return
PLKEYX: LDA GETCON ;Else Get Second Byte
ORA #$80 ; Set High Byte
RTS ; and Return
2018-01-28 18:30:49 +00:00
;Read Character from Console
GETKEY ;Same As RDKEY
;Wait for Character from Console
RDKEY: JSR PLKEY ;Read Character from Console
BEQ RDKEY ; Loop if None Received
RTS
;Delete Previous Character
DELCHR: LDA #$08 ;Load Backspace into Accumulator
JSR PRCHR ; and Print it
LDA #$20 ;Load Space into Accumulater
JSR PRCHR ; and Print it
LDA #$08 ;Load Backspace into Accumulator
JMP PRCHR ; and Print it
;Advance Character to Next line
NEWLIN: LDA #$0D ;Load C/R into Accumulator
JSR PRCHR ; and Print it
LDA #$0A ;Load L/F into Accumulater
; and fall into PRCHR
;Print Character to Console
PRCHR: STA PUTCON ;Write Character to Console
2018-01-28 18:30:49 +00:00
RTS
EXIT: BRK ;Return to Monitor
;Print Byte as Two-Digit Hex Number to Console
PRBYTE: PHA ;Save Accumulater
LSR ;Shift Hi Nybble to Low Nybble
LSR
LSR
LSR
JSR PRHEX ; and Print it
PLA ;Restore Accumulator
; and fall into PRHEX
;Print Low Nybble as Hex Digit to Console
PRHEX: AND #$0F ;Strip High Nybb
SED ;Set Decimal Flag for
CLC ; Addition Wizardry
ADC #$90 ;Convert to $90-$99,$00-$05
ADC #$40 ;Convert to $30-$39,$41-$46
CLD ;Clear Decimal Flag
JMP PRCHR ;Print Hex Digit and Return