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136 lines
4.3 KiB
Plaintext
136 lines
4.3 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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NULKEY EQU $00 ;No Key was Pressed ($00=Null)
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;Zero Page Locations
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SRCLO EQU $00 ;Source String Pointer (stdio.asm)
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SRCHI EQU $01
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DSTLO EQU $02 ;Destination String Pointer (string.asm)
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DSTHI EQU $03
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STKSAV EQU $04 ;Stack Pointer Storage
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RDSEED EQU $05 ;Pseudo-RANDOM Seed
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RANDOM EQU $06 ;Pseudo-RANDOM Number Storage
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TEMP0 EQU $07 ;Temporary Storage
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TEMP1 EQU $08
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TEMP2 EQU $09
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TEMP3 EQU $0A
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BLKSLO EQU $0B ;Block Start Address
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BLKSHI EQU $0C
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BLKELO EQU $0D ;Block End Address
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BLKEHI EQU $0E
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;Oric-1 Memory Locations
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CAPLCK EQU $020C ;Caps Lock: 127=Off, 255 = On
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;Oric-1 ROM Funxtions
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GTORKB EQU $E905 ;Get Character from Keyboard
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VDU EQU $F409 ;Print character in X to screen
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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: .DB $0C,$05 ;Address of Next Line
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.DB $00,$00 ;Basic Line Number (0)
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.DB $BF ;Token for Basic Call Command
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.DB $20 ;Space
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.DS "1294" ;Address of START Label
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.DB $00 ;End of Line
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.DB $00,$00 ;End of Program Marker
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START: TXS ;Save Stack Pointer
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STX STKSAV
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LDA #127 ;Set Caps Lock Off
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STA CAPLCK
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JMP MAIN ;Execute Program
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;Poll Character from Keyboard
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PLKEY: INC RDSEED ;Cycle the Random Seed (if not provided by system)
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JMP GTORKB ;Call ROM Key Reading function and return
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;Read Character from Console
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GETKEY; ;Drop into RDKEY routine
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;Wait for Character from Console
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RDKEY: JSR PLKEY ;Usually calls PLKEY
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BEQ RDKEY ; 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 PRCHR ;and Print to Screem
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;Advance Cursor to Next line
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NEWLIN: LDA RTNKEY ;Load Carriage Return and fall through to PRCHR
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;Print Character to Screen
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PRCHR: TAX ;Transfer Character to X Register
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JMP VDU ;Call ROM Print Function and Return
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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 CAPLCK
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LDX STKSAV ;Restore Stack Pointer
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TXS
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RTS ;and Return to Basic
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;Note: The following two functions replicate calls available
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;in the Apple-1 monitor and are included for test purposes
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;They will likely be removed before the final release
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;Print Byte as Two-Digit Hex Number to Console
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PRBYTE: PHA ;Save Accumulater
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LSR ;Shift Hi Nybble to Low Nybble
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LSR
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LSR
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LSR
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JSR PRHEX ; and Print it
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PLA ;Restore Accumulator
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; and fall into PRHEX
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;Print Low Nybble as Hex Digit to Console
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PRHEX: AND #$0F ;Strip High Nybble
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CMP #$0A ;If Low Nybble >= 10
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BCC PRHEXC ;
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ADC #$06 ; Convert ':' to 'A'...
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PRHEXC: ADC #$30 ;Convert to ASCII Character
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JMP PRCHR ;Print Hex Digit and Return
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;Functions to set String Pointers
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;Used by memory, stdio, stdlin, string, and stringx libraries
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;Initialize Destination String Pointer
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SETDST: STX DSTLO ;Save Destination String Pointer
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STY DSTHI
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RTS
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;Initialize Source String Pointer and Index
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SETSRC: STX SRCLO ;Save Source String Pointer
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STY SRCHI
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LDY #$00 ;Initialize Index Into String
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RTS
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