;ProDOS Zero Page Command = $42 ;ProDOS Command Unit = $43 ;ProDOS unit (SDDD0000) BufferLo = $44 BufferHi = $45 BlockLo = $46 BlockHi = $47 ; ProDOS Error Codes IOError = $27 NoDevice = $28 WriteProtect = $2B InputByte = $c08e+SLOT*$10 OutputByte = $c08d+SLOT*$10 InputFlags = $c08b+SLOT*$10 OutputFlags = $c087+SLOT*$10 ReadBlockCommand = $01 WriteBlockCommand = $02 GetTimeCommand = $03 ChangeDriveCommand = $04 ExecCommand = $05 LoadFileCommand = $06 SaveFileCommand = $07 MenuCommand = $08 InputString = $fd67 PrintChar = $fded .org SLOT*$100 + $C000 ;ID bytes for booting and drive detection cpx #$20 ;ID bytes for ProDOS and the cpx #$00 ; Apple Autostart ROM cpx #$03 ; ldx #SLOT*$10 stx $2b stx Unit ;force EPROM to second page on boot lda #$3f ;set all flags high and page 3 of EPROM for menu PageJump: sta OutputFlags jmp Start ;this jump is only called if coming in from PageJump with A=$2f ;entry points for ProDOS DriverEntry: lda #$0f ;set all flags high and page 0 of EPROM sta OutputFlags Start: jsr $c300 ;enable 80 columns lda #$05 ;execute command jsr SendByte ldy #$00 sendHelp: lda HelpCommand,y beq endSendHelp jsr SendByte iny bne sendHelp endSendHelp: lda #$00 jsr SendByte jsr DumpOutput lda $33 pha lda #$a4 sta $33 GetCommand: jsr InputString lda $0200 cmp #$8d ;skip when return found beq GetCommand jsr SendCommand clc bcc GetCommand SendCommand: lda #$05 ;send command 5 = exec jsr SendByte ldy #$00 getInput: lda $0200,y cmp #$8d beq sendNullTerminator and #$7f jsr SendByte iny bne getInput sendNullTerminator: lda #$00 jsr SendByte DumpOutput: jsr GetByte cmp #$00 beq endOutput jsr PrintChar clc bcc DumpOutput endOutput: rts HelpCommand: .byte "a2help",$00 SendByte: pha waitWrite: lda InputFlags rol rol bcs waitWrite pla sta OutputByte lda #$1e ; set bit 0 low to indicate write started sta OutputFlags finishWrite: lda InputFlags rol rol bcc finishWrite lda #$1f sta OutputFlags rts GetByte: lda #$1d ;set read flag low sta OutputFlags waitRead: lda InputFlags rol bcs waitRead lda InputByte pha lda #$1f ;set all flags high sta OutputFlags finishRead: lda InputFlags rol bcc finishRead pla end: rts .repeat 251-