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90 lines
2.9 KiB
Plaintext
90 lines
2.9 KiB
Plaintext
; c02 Program Initialization Code for Commander X16
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; Compatible with x16emu Release 34
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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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; $00-$01 ;Miscellaneous Pointer
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; $02-$21 ;ABI Registers
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; $22-$52 ;Used by Basic graphics commands
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XMBANK EQU $53 ;Extended Memory Bank
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XMADDR EQU $54 ;Ext Memory Address
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SRCPTR EQU $56 ;Source Pointer
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DSTPTR EQU $58 ;Destination Pointer
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BLKPTR EQU $5A ;Block Pointer
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STKPTR EQU $5C ;Stack Pointer
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USRPTR EQU $5E ;User Pointer
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RANDOM EQU $62 ;Random Number Storage
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RDSEED EQU $63 ;Random Seed
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TEMP0 EQU $64 ;Temporary Variables
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TEMP1 EQU $65
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TEMP2 EQU $66
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TEMP3 EQU $67
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TMPPTR EQU $68 ;Temporary Pointer
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SYSBFP EQU $6A ;Position in System Buffr
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; $6B-$6F ;Unused
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; $70-7F ;Free Zero-Page for Applications
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; $80-$83 ;Used by Kernal and DOS
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; $A4-$A8 ;Reserved for KERNAL/DOS/BASIC
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; $A9-$FF ;Used by BASIC
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;Other Constants
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SYSBFL EQU 128 ;System Buffer Length [Max String Length]
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;Other Variables - User Storage Area
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SYSBFR EQU $0700 ;System Buffer
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; $0781-$07F5 ;Unused
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BLKBGN EQU $07F6 ;Block Start Address
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BLKEND EQU $07F8 ;Block End Address
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BLKLEN EQU $07FA ;Block Length
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STKSAV EQU $07FB ;Machine Stack Storage
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STKBGN EQU $07FC ;Stack Start
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STKEND EQU $07FE ;Stack End
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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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SEC ;Set Screen Mode
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LDA #0 ;to 40x30 Text
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JSR $FF5F ;using SCRMOD
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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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INCLUDE "prbyte.a02" ;PRBYTE and PRHEX routine
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INCLUDE "putstr.a02" ;PUTSTR routine
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