mirror of
https://github.com/tjboldt/Apple2-IO-RPi.git
synced 2024-11-24 15:31:14 +00:00
215 lines
8.8 KiB
Plaintext
215 lines
8.8 KiB
Plaintext
ca65 V2.18 - Raspbian 2.19-1
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Main file : DriveFirmware.asm
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Current file: DriveFirmware.asm
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000000r 1 ; Copyright Terence J. Boldt (c)2020-2023
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000000r 1 ; Use of this source code is governed by an MIT
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000000r 1 ; license that can be found in the LICENSE file.
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000000r 1
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000000r 1 ; This file contains the source for the firmware
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000000r 1 ; that allows the Apple II to boot from the card
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000000r 1 ; and for ProDOS to recognize the card as two
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000000r 1 ; hard drivers
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000000r 1
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000000r 1 ;ProDOS Zero Page
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000000r 1 Command = $42 ;ProDOS Command
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000000r 1 Unit = $43 ;ProDOS unit (SDDD0000)
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000000r 1 BufferLo = $44
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000000r 1 BufferHi = $45
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000000r 1 BlockLo = $46
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000000r 1 BlockHi = $47
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000000r 1
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000000r 1 ; ProDOS Error Codes
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000000r 1 IOError = $27
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000000r 1 NoDevice = $28
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000000r 1 WriteProtect = $2B
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000000r 1
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000000r 1 InputByte = $c08e+SLOT*$10
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000000r 1 OutputByte = $c08d+SLOT*$10
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000000r 1 InputFlags = $c08b+SLOT*$10
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000000r 1 OutputFlags = $c087+SLOT*$10
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000000r 1
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000000r 1 ReadBlockCommand = $01
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000000r 1 WriteBlockCommand = $02
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000000r 1 GetTimeCommand = $03
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000000r 1 ChangeDriveCommand = $04
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000000r 1 ExecCommand = $05
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000000r 1 LoadFileCommand = $06
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000000r 1 SaveFileCommand = $07
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000000r 1 MenuCommand = $08
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000000r 1
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000000r 1 .org SLOT*$100 + $C000
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00C700 1 ;ID bytes for booting and drive detection
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00C700 1 E0 20 cpx #$20 ;ID bytes for ProDOS and the
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00C702 1 E0 00 cpx #$00 ; Apple Autostart ROM
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00C704 1 E0 03 cpx #$03 ;
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00C706 1
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00C706 1 A2 70 ldx #SLOT*$10
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00C708 1 86 2B stx $2b
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00C70A 1 86 43 stx Unit
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00C70C 1
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00C70C 1 ;force EPROM to second page on boot
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00C70C 1 A9 3F lda #$3f ;set all flags high and page 3 of EPROM for menu
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00C70E 1 PageJump:
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00C70E 1 8D F7 C0 sta OutputFlags
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00C711 1 4C 1C C7 jmp Start ;this jump is only called if coming in from PageJump with A=$0f
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00C714 1
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00C714 1 ;entry points for ProDOS
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00C714 1 DriverEntry:
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00C714 1 A9 0F lda #$0f ;set all flags high and page 0 of EPROM
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00C716 1 8D F7 C0 sta OutputFlags
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00C719 1 4C 32 C7 jmp Driver
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00C71C 1
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00C71C 1 ;load first two blocks and execute to boot
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00C71C 1 Start:
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00C71C 1 A9 01 lda #$01 ;set read command
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00C71E 1 85 42 sta Command
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00C720 1
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00C720 1 A9 00 lda #$00 ;block 0
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00C722 1 85 46 sta BlockLo
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00C724 1 85 47 sta BlockHi
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00C726 1 85 44 sta BufferLo ;buffer at $800
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00C728 1 A9 08 lda #$08
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00C72A 1 85 45 sta BufferHi
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00C72C 1 20 32 C7 jsr Driver ;get the block
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00C72F 1
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00C72F 1 4C 01 08 jmp $801 ;execute the block
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00C732 1
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00C732 1 ; ProDOS Driver code
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00C732 1 ; First check that this is the right drive
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00C732 1 Driver:
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00C732 1 A6 43 ldx Unit
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00C734 1 A5 42 lda Command; Check which command is being requested
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00C736 1 F0 0C beq GetStatus ;0 = Status command
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00C738 1 C9 01 cmp #ReadBlockCommand
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00C73A 1 F0 10 beq ReadBlockAndSetTime
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00C73C 1 C9 02 cmp #WriteBlockCommand
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00C73E 1 F0 54 beq WriteBlock
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00C740 1 38 sec ;set carry as we don't support any other commands
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00C741 1 A9 53 lda #$53 ;Invalid parameter error
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00C743 1 60 rts
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00C744 1
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00C744 1 ; ProDOS Status Command Handler
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00C744 1 GetStatus:
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00C744 1 A2 FF ldx #$ff ;low byte number of blocks
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00C746 1 A0 FF ldy #$ff ;high byte number of blocks
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00C748 1 A9 00 lda #$0 ;zero accumulator and clear carry for success
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00C74A 1 18 clc
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00C74B 1 60 rts
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00C74C 1
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00C74C 1 ; ProDOS Read Block Command
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00C74C 1 ReadBlockAndSetTime:
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00C74C 1 A5 47 lda BlockHi ; only get the time if block 0002
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00C74E 1 D0 18 bne readBlock
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00C750 1 A5 46 lda BlockLo
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00C752 1 C9 02 cmp #$02
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00C754 1 D0 12 bne readBlock
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00C756 1 A0 00 ldy #$00 ;Get the current time on each block read for now
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00C758 1 A9 03 lda #GetTimeCommand
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00C75A 1 20 C0 C7 jsr SendByte
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00C75D 1 getTimeByte:
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00C75D 1 20 DE C7 jsr GetByte
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00C760 1 99 90 BF sta $bf90,y
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00C763 1 C8 iny
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00C764 1 C0 04 cpy #$04
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00C766 1 D0 F5 bne getTimeByte
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00C768 1 readBlock:
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00C768 1 A9 01 lda #ReadBlockCommand ;read the block after setting the clock
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00C76A 1 20 C0 C7 jsr SendByte
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00C76D 1 A5 46 lda BlockLo
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00C76F 1 20 C0 C7 jsr SendByte
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00C772 1 A5 47 lda BlockHi
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00C774 1 20 C0 C7 jsr SendByte
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00C777 1 8A txa
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00C778 1 20 C0 C7 jsr SendByte
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00C77B 1 A0 00 ldy #$0
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00C77D 1 20 8B C7 jsr read256
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00C780 1 E6 45 inc BufferHi
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00C782 1 20 8B C7 jsr read256
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00C785 1 C6 45 dec BufferHi
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00C787 1 A9 00 lda #$0 ;zero accumulator and clear carry for success
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00C789 1 18 clc
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00C78A 1 60 rts
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00C78B 1
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00C78B 1 read256:
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00C78B 1 20 DE C7 jsr GetByte
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00C78E 1 91 44 sta (BufferLo),y
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00C790 1 C8 iny
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00C791 1 D0 F8 bne read256
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00C793 1 60 rts
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00C794 1
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00C794 1 ; ProDOS Write Block Command
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00C794 1 WriteBlock:
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00C794 1 A9 02 lda #WriteBlockCommand
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00C796 1 20 C0 C7 jsr SendByte
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00C799 1 A5 46 lda BlockLo
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00C79B 1 20 C0 C7 jsr SendByte
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00C79E 1 A5 47 lda BlockHi
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00C7A0 1 20 C0 C7 jsr SendByte
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00C7A3 1 8A txa
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00C7A4 1 20 C0 C7 jsr SendByte
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00C7A7 1 A0 00 ldy #$0
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00C7A9 1 20 B7 C7 jsr write256
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00C7AC 1 E6 45 inc BufferHi
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00C7AE 1 20 B7 C7 jsr write256
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00C7B1 1 C6 45 dec BufferHi
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00C7B3 1 A9 00 lda #$0 ;zero accumulator and clear carry for success
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00C7B5 1 18 clc
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00C7B6 1 60 rts
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00C7B7 1
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00C7B7 1 write256:
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00C7B7 1 B1 44 lda (BufferLo),y
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00C7B9 1 20 C0 C7 jsr SendByte
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00C7BC 1 C8 iny
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00C7BD 1 D0 F8 bne write256
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00C7BF 1 60 rts
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00C7C0 1
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00C7C0 1 SendByte:
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00C7C0 1 48 pha
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00C7C1 1 waitWrite:
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00C7C1 1 AD FB C0 lda InputFlags
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00C7C4 1 2A rol
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00C7C5 1 2A rol
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00C7C6 1 B0 F9 bcs waitWrite
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00C7C8 1 68 pla
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00C7C9 1 8D FD C0 sta OutputByte
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00C7CC 1 A9 0E lda #$0e ; set bit 0 low to indicate write started
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00C7CE 1 8D F7 C0 sta OutputFlags
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00C7D1 1 finishWrite:
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00C7D1 1 AD FB C0 lda InputFlags
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00C7D4 1 2A rol
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00C7D5 1 2A rol
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00C7D6 1 90 F9 bcc finishWrite
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00C7D8 1 A9 0F lda #$0f
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00C7DA 1 8D F7 C0 sta OutputFlags
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00C7DD 1 60 rts
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00C7DE 1
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00C7DE 1 GetByte:
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00C7DE 1 A9 0D lda #$0d ;set read flag low
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00C7E0 1 8D F7 C0 sta OutputFlags
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00C7E3 1 waitRead:
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00C7E3 1 AD FB C0 lda InputFlags
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00C7E6 1 2A rol
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00C7E7 1 B0 FA bcs waitRead
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00C7E9 1 AD FE C0 lda InputByte
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00C7EC 1 48 pha
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00C7ED 1 A9 0F lda #$0f ;set all flags high
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00C7EF 1 8D F7 C0 sta OutputFlags
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00C7F2 1 finishRead:
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00C7F2 1 AD FB C0 lda InputFlags
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00C7F5 1 2A rol
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00C7F6 1 90 FA bcc finishRead
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00C7F8 1 68 pla
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00C7F9 1 end:
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00C7F9 1 60 rts
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00C7FA 1
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00C7FA 1 00 00 .repeat 251-<end
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00C7FC 1 .byte 0
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00C7FC 1 .endrepeat
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00C7FC 1
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00C7FC 1 00 00 .byte 0,0 ;0000 blocks = check status
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00C7FE 1 17 .byte 23 ;bit set(0=status 1=read 2=write) unset(3=format, 4/5=number of volumes, 6=interruptable, 7=removable)
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00C7FF 1 14 .byte DriverEntry&$00FF ;low byte of entry
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00C800 1
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00C800 1
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