mirror of https://github.com/RevCurtisP/C02.git
114 lines
3.4 KiB
Plaintext
114 lines
3.4 KiB
Plaintext
; Program initialization code for Oric-1
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;System Specific ASCII Key Mappings
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DELKEY EQU $7F ;Delete/Backspace Key (Delete)
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ESCKEY EQU $1B ;Escape/Stop Key (Escape)
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RTNKEY EQU $0D ;Return/Enter Key ($0D=Carriage Return)
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;Zero Page Locations
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SRCLO EQU $10 ;Source String Pointer (stdio.asm)
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SRCHI EQU $11
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DSTLO EQU $12 ;Destination String Pointer (string.asm)
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DSTHI EQU $13
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BFRLO EQU $14 ;Work Buffer Pointer
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BFRHI EQU $15
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TEMP0 EQU $16 ;Temporary Storage
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TEMP1 EQU $17
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TEMP2 EQU $18
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TEMP3 EQU $19
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RDSEED EQU $1A ;Pseudo-RANDOM Seed
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RANDOM EQU $1B ;Pseudo-RANDOM Number Storage
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; EQU $1C ;Unused
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; EQU $1D ;Unused
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BLKLEN EQU $1F ;Block Length
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BLKSLO EQU $20 ;Block Start Address
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BLKSHI EQU $21
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BLKELO EQU $22 ;Block End Address
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BLKEHI EQU $23
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STKSLO EQU $24 ;Stack Start LSB
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STKSHI EQU $25 ;Stack Start MSB
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STKELO EQU $26 ;Stack End LSB
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STKEHI EQU $27 ;Stack End MSB
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;Oric-1 Tape images have the file extension ".tap"
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;and have the following header prepended to the code
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; $16,$16,$16, $16 Tape Syncronization Pattern
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; $24 Tape Syncronization Byte
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; $00,$00 Filler Bytes
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; $00 Basic Program
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; $00 No Autostart ($80 for Autostart)
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; $xx,$xx MSB, LSB of End Address
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; $05,$01 MSB, LSB of Start Address
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; $00 Filler Byte
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; "filename" Up to 16 ASCII Characters
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; $00 Strint Terminator
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;The End Address is actually one higher than the last
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;byte of the Basic program and the first byte of Basic
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;variable space. so the compiled program need to have
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;one dummy byte added to the end.
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ORG $0501 ;Basic Program Start Address
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BASIC: .DC $0C,$05 ;Address of Next Line
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.DC $00,$00 ;Basic Line Number (0)
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.DC $BF ;Token for Basic Call Command
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.DC $20 ;Space
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.DC "1294" ;Address of START Label
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.DC $00 ;End of Line
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.DC $00,$00 ;End of Program Marker
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START: LDA #127 ;Set Caps Lock Off
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STA $020C
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LDA #$0B ;Turn Cursor On, Keyclick Off
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STA $026A ;and Protect Columns 0 & 1
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JMP MAIN ;Execute Program
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;Poll Character from Keyboard
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POLKEY: INC RDSEED ;Cycle the Random Seed
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JMP $E905 ;Execute GETORKB
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;Read Character from Console
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GETKEY EQU POLKEY ;Aliased to POLKEY
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;Wait for Character from Console
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GETCHR: JSR GETKEY ;Calls GETKEY
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BEQ GETCHR ; until a non-zero is returned
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RTS
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;Delete Previous Character
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DELCHR: LDA #DELKEY ;Load Delete Character
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BNE PUTCHR ;and Print to Screem
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;Advance Cursor to Next line
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NEWLIN EQU $CB9F ;Basic NEWLINE Routine ($CBF0 for ATMOS)
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; LDA #$0D ;Load Carriage Return
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; JSR PUTCHR ;and Print It
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; LDA #$0A ;Load Line Feed and fall through to PRCHR
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;Print Character to Screen
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PUTCHR: TAX ;Transfer Character to X Register
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JMP $F409 ;Execute VDU Routine
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;Print String to Screen
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PUTSTR: TXA ;Copy LSB to A6
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JMP $CCB0 ;Execute BASIC String Print Routine
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;Get End of Free Memory
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RAMTOP: LDX $A6 ;Load HIMEM LSB
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LDY $A7 ;Load HIMEM MSB
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RTS
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;Exit Program and Return to Operating System or Monitor
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EXIT: LDA #255 ;Set Caps Lock On
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STA $020C
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JMP $C003 ;BASIC Warm Start
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INCLUDE "../include/prbyte.a02" ;PRBYTE and PRHEX routines
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