;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 $0D     ;Return/Enter Key     (Carriage Return)

;Zero Page Locations
SRCPTR  EQU $30     ;Source String Pointer (stdio.a02)
DSTPTR  EQU $32     ;Destination String Pointer (string.a02)
BFRPTR  EQU $34     ;Work Buffer Pointer
BFRLO   EQU $34
BFRHI   EQU $35
BLKPTR  EQU $36     ;Block Segment Pointer (block.a02)
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

BLKBGN  EQU $46
BLKEND  EQU $48
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 _GETCH Routine

;Poll Character from Keyboard
POLKEY: BRK         ;Exit Emulator
        

;Wait for Character from Console
GETCHR: JSR GETKEY  ;Get Key from Console
        BEQ GETCHR  ;If None Pressed, Loop
        RTS

;Read Character from stdin
RDCHAR: LDA $FFEA   ;Read Character from STDIN
        CMP #$FF    ;If EOF
        BNE RDCHAX
        LDA #0      ;  Set to ASCII NUL
RDCHAX  ORA #0      ;Set Flags
        RTS

;Delete Previous Character
DELCHR: LDA #$08    ;Load Backspace into Accumulator
        JSR PUTCHR  ;  and Print it
        LDA #$20    ;Load Space into Accumulator
        JSR PUTCHR  ;  and Print it
        LDA #$08    ;Load Backspace into Accumulator
        JMP PUTCHR  ;  and Print it

;Advance Character to Next line
NEWLIN: LDA #$0D    ;Load Carriage Return into Accumulator
        JSR PUTCHR  ;  and Print it
        LDA #$0A    ;Load Line Feed into Accumulator
        JMP PUTCHR  ;  and Print it

;Print Character to Console
PUTCHR  EQU $FFE3   ;Emulator CHROUT Routine

;Write Character to stdout
PRCHAR: STA $FFEA   ;Read Character from STDIN
        RTS

EXIT    EQU $FFEC   ;Emulator SHUTDN Routine

FSCMD   EQU $FFE6   ;run6502 File System Command Routine

        INCLUDE "prbyte.a02" ;PRBYTE and PRHEX routines
        INCLUDE "putstr.a02" ;PUTSTR routine