;run6502 program initialization code for c02 programs

;System Specific ASCII Key Mappings
DELKEY  EQU $08     ;Delete/Backspace Key (Backspace)
ESCKEY  EQU $1B     ;Escape/Stop Key      (Escape)
RTNKEY  EQU $0D     ;Return/Enter Key     (Carriage Return)

;Zero Page Variables
;       $00-$06     ;Reserved

XMBANK  EQU $07     ;Extended Memory Bank
XMADDR  EQU $08     ;Extended Memory Address

SRCPTR  EQU $10     ;Source Pointer
DSTPTR  EQU $12     ;Destination Pointer

TEMP0   EQU $14     ;Temporary Storage
TEMP1   EQU $15
TEMP2   EQU $16
TEMP3   EQU $17
TMPPTR  EQU $18     ;Temporary Pointer

LSTPTR  EQU $1A     ;List Pointer
USRPTR  EQU $1C     ;User Pointer
;           $1E     ;Reserved

BLKLEN  EQU $1F     ;Block Segment Length
BLKPTR  EQU $20     ;Block Segment Pointer
BLKBGN  EQU $22     ;Block Start Address
BLKEND  EQU $24     ;Block End Address

STKPTR  EQU $26     ;Stack Pointer
STKBGN  EQU $28     ;Stack Start Addres
STKEND  EQU $2A     ;Stack End Address

RDSEED  EQU $2C     ;Pseudo-RANDOM Seed
RANDOM  EQU $2D     ;Pseudo-RANDOM Number Storage

SYSBFP  EQU $2E     ;Position in System Buffer
.STKSAV EQU $2F     ;Stack Pointer Storage

INTACC  EQU $30     ;Integer Accumulator
INTOVR  EQU $32     ;Integer Overflow
INTARG  EQU $34     ;Integer Argument

;       $34-$3F     ;Reserved
;       $40-$FF     ;Free Zero Page for Applications

SYSBFL  EQU 128     ;System Buffer Size (Max String Size)
SYSBFR  EQU $0200   ;System Buffer
;     $0281-$03FF   ;Unused

;Emulated BIOS System Calls
.GETCH  EQU $FFE0   ;-K  Read Keyboard
.PUTCH  EQU $FFE3   ;-C  Write to Screen
FSCMD   EQU $FFE6   ;-F  filecmd() - File I/O Command Processor
SYSCMD  EQU $FFE9   ;-S  syscmd()  - System Command Processor
XMCMD   EQU $FFEC   ;-E  Extended Memory 
.STDIO  EQU $FFEF   ;-M  Memory Mapped stdio
EXIT    EQU $FFF0   ;-X  Exit Emulator

;           $0000   ;-N  NMI Vector

ARGV    EQU $0300   ;Command Line Arguments Bu
        
        ORG $0400   ;START at RAM midpoint

START:  JMP MAIN    ;Execute Program

;Read Character from Console
GETKEY  EQU .GETCH  ;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 .STDIO  ;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 .PUTCH ;Emulator CHROUT Routine

;Write Character to stdout
PRCHAR: STA .STDIO  ;Read Character from STDIN
        RTS

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