mirror of
https://github.com/tjboldt/Apple2-IO-RPi.git
synced 2024-11-24 15:31:14 +00:00
82 lines
2.0 KiB
NASM
82 lines
2.0 KiB
NASM
; Copyright Terence J. Boldt (c)2020-2024
|
|
; Use of this source code is governed by an MIT
|
|
; license that can be found in the LICENSE file.
|
|
|
|
; This file formerly contained the source for the
|
|
; firmware that had a pseudo command prompt
|
|
; but is now empty except required common bytes
|
|
|
|
;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
|
|
|
|
.org SLOT*$100 + $C000
|
|
;ID bytes for booting and drive detection
|
|
cpx #$20 ;ID bytes for ProDOS
|
|
cpx #$00 ;
|
|
cpx #$03 ;
|
|
cpx #$3C ;ID byte for Autostart ROM
|
|
|
|
lda #$3f ;set all flags high and page 3 of EPROM for menu
|
|
jmp PageJump
|
|
|
|
;The following bytes must exist in this location for Pascal communications
|
|
;as they are standard pointers for entry points
|
|
.byte CommInit&$00FF ;low byte of rts for init of Pascal comms
|
|
.byte $43 ; low byte of read for Pascal comms
|
|
.byte $49 ; low byte of write for Pascal comms
|
|
.byte $4F ; low byte of rts for status of Pascal comms
|
|
|
|
CommInit:
|
|
lda #$0f ; set all flags high and page 0 for comm driver
|
|
sta OutputFlags
|
|
ldx #$00 ; set error code to 0 for success
|
|
rts
|
|
|
|
PageJump:
|
|
sta OutputFlags
|
|
jmp Start ;this jump is only called if coming in from PageJump with A=$0f
|
|
|
|
;entry points for ProDOS
|
|
DriverEntry:
|
|
lda #$0f ;set all flags high and page 0 of EPROM
|
|
sta OutputFlags
|
|
jmp Start ; this is never called as the EPROM page changes
|
|
|
|
;load first two blocks and execute to boot
|
|
Start:
|
|
end:
|
|
rts
|
|
|
|
.repeat 251-<end
|
|
.byte 0
|
|
.endrepeat
|
|
|
|
.byte 0,0 ;0000 blocks = check status
|
|
.byte 23 ;bit set(0=status 1=read 2=write) unset(3=format, 4/5=number of volumes, 6=interruptable, 7=removable)
|
|
.byte DriverEntry&$00FF ;low byte of entry
|
|
|