mirror of
https://github.com/tjboldt/Apple2-IO-RPi.git
synced 2024-06-01 19:41:33 +00:00
87 lines
1.6 KiB
NASM
87 lines
1.6 KiB
NASM
;ProDOS Zero Page
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Command = $42 ;ProDOS Command
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Unit = $43 ;ProDOS unit (SDDD0000)
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BufferLo = $44
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BufferHi = $45
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BlockLo = $46
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BlockHi = $47
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; ProDOS Error Codes
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IOError = $27
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NoDevice = $28
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WriteProtect = $2B
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InputByte = $c08e+SLOT*$10
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OutputByte = $c08d+SLOT*$10
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InputFlags = $c08b+SLOT*$10
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OutputFlags = $c087+SLOT*$10
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ReadBlockCommand = $01
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WriteBlockCommand = $02
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GetTimeCommand = $03
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ChangeDriveCommand = $04
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ExecCommand = $05
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LoadFileCommand = $06
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SaveFileCommand = $07
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.org SLOT*$100 + $C000
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;ID bytes for booting and drive detection
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cpx #$20 ;ID bytes for ProDOS and the
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cpx #$00 ; Apple Autostart ROM
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cpx #$03 ;
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ldx #SLOT*$10
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stx $2b
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stx Unit
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;force EPROM to second page on boot
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lda #$1f ;set all flags high and page 1 of EPROMi
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PageJump:
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sta OutputFlags
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jmp Start
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;entry points for ProDOS
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DriverEntry:
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lda #$0f ;set all flags high and page 0 of EPROM
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sta OutputFlags
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;since the firmware page changes to 0, this falls through to the driver
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Start:
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jsr $fc58
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ldy #$00
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PrintString:
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lda Text,y
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ora #$80
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beq GetChar
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jsr $fded
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iny
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bne PrintString
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GetChar:
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jsr $fd1b
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sec ;subtract ascii "1" to get 0 - 3 from "1" to "4"
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sbc #$b1
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asl ;put in top nibble as EPROM page
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asl
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asl
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asl
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ora #$0f ;set all flags high
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jmp PageJump
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Text:
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.byte "1. Boot",$8d
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.byte "2. File Access",$8d
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.byte "3. Command Line",$8d
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end:
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rts
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.repeat 251-<end
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.byte 0
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.endrepeat
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.byte 0,0 ;0000 blocks = check status
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.byte 7 ;bit set(0=status 1=read 2=write) unset(3=format, 4/5=number of volumes, 6=interruptable, 7=removable)
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.byte DriverEntry&$00FF ;low byte of entry
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