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https://github.com/RevCurtisP/C02.git
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89 lines
3.4 KiB
Plaintext
89 lines
3.4 KiB
Plaintext
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; c02 Program Initialization Code for Commander X16
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;PETSCII Key Mappings
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DELKEY EQU $14 ;Delete/Backspace Key (Delete)
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ESCKEY EQU $03 ;Escape/Stop Key (RUN/STOP)
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RTNKEY EQU $0D ;Return/Enter Key (RETURN)
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;Zero Page System Variables - Assumes Usage is Same as C64
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XMBANK EQU $0A ;Extended Memory Bank (Load/Verify Flag)
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XADRLO EQU $0B ;Ext Memory Address LSB (Text Index/Array Size)
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XADRHI EQU $0C ;Ext Memory Address MSB (Array Dimension Fkags)
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SRCPTR EQU $22 ;Source Pointer [Temporary Pointers]
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SRCLO EQU $22 ;Source Pointer LSB [Temporary Pointers]
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SRCHI EQU $23 ;Source Pointer MSB [Temporary Pointers]
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DSTPTR EQU $24 ;Destination Pointer [Temporary Pointers]
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DSTLO EQU $24 ;Destination Pointer LSB [Temporary Pointers]
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DSTHI EQU $25 ;Destination Pointer MSB [Temporary Pointers]
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BLKLO EQU $26 ;Block Pointer LSB [Floating Point Work Area]
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BLKHI EQU $27 ;Block Pointer MSB [Floating Point Work Area]
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STKLO EQU $28 ;Stack Pointer LSB [Floating Point Work Area]
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STKHI EQU $29 ;Stack Pointer MSB [Floating Point Work Area]
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BFRLO EQU $35 ;Buffer Pointer LSB [Temporary String Pointer]
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BFRHI EQU $36 ;Buffer Pointer MSB [Temporary String Pointer]
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RDSEED EQU $A2 ;Random Seed [Software Jiffy Clock (Low Byte)]
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TEMP0 EQU $FB ;Temporary Variable [Unused Byte]
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TEMP1 EQU $FC ;Temporary Variable [Unused Byte]
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TEMP2 EQU $FD ;Temporary Variable [Unused Byte]
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TEMP3 EQU $FE ;Temporary Variable [Unused Byte]
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;Other Variables - Top of Extended System RAM Area
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BLKSLO EQU $07F4 ;Block Start LSB [Unused Byte]
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BLKSHI EQU $07F5 ;Block Start MSB [Unused Byte]
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BLKELO EQU $07F6 ;Block End LSB [Unused Byte]
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BLKEHI EQU $07F7 ;Block End MSB [Unused Byte]
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BLKLEN EQU $07F8 ;Block Length [Unused Byte]
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RANDOM EQU $07F9 ;Random Number Storage [Unused Byte]
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STKSAV EQU $07FA ;Machine Stack Storage [Unused Byte]
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STKSLO EQU $07FC ;Stack Start LSB [Unused Byte]
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STKSHI EQU $07FD ;Stack Start MSB [Unused Byte]
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STKELO EQU $07FE ;Stack End LSB [Unused Byte]
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STKEHI EQU $07FF ;Stack End MSB [Unused Byte]
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;Machine Language Basic Stub - Same as Commodore 64
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ORG $0801 ;Start of Basic Program
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BASIC: DC $0C, $08 ;Pointer to Next Line
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DC $00, $00 ;Line Number (0)
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DC $9E ;SYS
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DC $20 ;' '
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DC $32, $30, $36 ,$32 ;"2062"
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DC $00 ;End of Line Marker
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DC $00, $00 ;End of Basic Program
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START: TSX ;Get Stack Pointer
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STX STKSAV ;and Save for Exit
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JMP MAIN ;Execute Program
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EXIT: LDX STKSAV ;Retrieve Saved Stack Pointer
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TXS ;and Restore It
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RTS ;Return to BASIC
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;Poll Keyboard for Character
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POLKEY EQU $FFE4 ;Aliased to Kernal GETIN Routine
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;Get Character from Keyboard
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GETKEY EQU POLKEY ;Aliased to POLKEY Routine
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;Wait for Character from Keyboard
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GETCHR: JSR GETKEY ;Poll Keyboard
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BEQ GETCHR ;If No Key, Loop
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RTS
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;Print Character to Console
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PUTCHR EQU $FFD2 ;Aliased to CHROUT Routine
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;Delete Previous Character
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DELCHR: LDA #DELKEY ;Load Delete Character
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JMP PUTCHR ;Print and Return
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;Advance Character to Next line
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NEWLIN: LDA #RTNKEY ;Load Return Character
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JMP PUTCHR ;Print and Return
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PUTSTR: TXA ;Copy LSB to Accumulator
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JMP $CBD2 ;Execute STROUT
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INCLUDE "../include/prbyte.a02" ;PRBYTE and PRHEX routine
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