AppleWin/firmware/HDD/hddrvr.a65
2006-02-25 20:54:57 +00:00

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;AppleWin : An Apple //e emulator for Windows
;
;Copyright (C) 1994-1996, Michael O'Brien
;Copyright (C) 1999-2001, Oliver Schmidt
;Copyright (C) 2002-2005, Tom Charlesworth
;Copyright (C) 2006, Tom Charlesworth, Michael Pohoreski
;
;AppleWin is free software; you can redistribute it and/or modify
;it under the terms of the GNU General Public License as published by
;the Free Software Foundation; either version 2 of the License, or
;(at your option) any later version.
;
;AppleWin is distributed in the hope that it will be useful,
;but WITHOUT ANY WARRANTY; without even the implied warranty of
;MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;GNU General Public License for more details.
;
;You should have received a copy of the GNU General Public License
;along with AppleWin; if not, write to the Free Software
;Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
;
; Description: Firmware for harddisk card
;
; Author: Copyright (c) 2005, Robert Hoem
;
; Modified by Tom Charlesworth:
; . Fixed so it can be assembled by a65 v1.06
; . TO DO: Make code relocatable
;
; constants
hd_execute = $c0f0
hd_error = $c0f1
hd_command = $c0f2
hd_unitnum = $c0f3
hd_memblock = $c0f4
hd_diskblock = $c0f6
hd_nextbyte = $c0f8
command = $42
unitnum = $43
memblock = $44
diskblock = $46
slot6 = $c600
OS = $0801
; The Autoboot rom will call this.
; This is also the entry point for such things as IN#7 and PR#7
;; code
*= $c700 ; org $c700
start
; Autoboot and ProDos look at the following few opcodes to detect block devices
lda #$20
lda #$00
lda #$03
lda #$3C
; Lets check to see if there's an image ready
lda #$00
sta hd_command
; Slot 7, disk 1
lda #$70 ; Slot# << 4
sta hd_unitnum
lda hd_execute
; error capturing code. Applewin is picky
; about code assigning data to registers and
; memory. The safest method is via I/O port
pha
lda hd_error
clc
cmp #1
bne noerr0
sec
noerr0
pla
bcc hdboot
; no image ready, boot diskette image instead
jmp slot6
; image ready. Lets boot from it.
; we want to load block 1 from s7,d1 to $800 then jump there
hdboot
lda #$70 ; Slot# << 4
sta unitnum
lda #$0
sta memblock
sta diskblock
sta diskblock+1
lda #$8
sta memblock+1
lda #$1
sta command
jsr cmdproc
bcc goload
jmp slot6
goload
; X=device
ldx #$70 ; Slot# << 4
jmp OS
; entry point for Prodos' block driver
; simple really. Copy the command from $42..$47
; to our I/O ports then execute command
cmdproc
clc
lda $42
sta hd_command
lda $43
sta hd_unitnum
lda $44
sta hd_memblock
lda $45
sta hd_memblock+1
lda $46
sta hd_diskblock
lda $47
sta hd_diskblock+1
lda hd_execute
; check for error
pha
lda command
cmp #1
bne skipSread
jsr sread
skipSread
lda hd_error
clc
cmp #1
bne noerr2
sec
noerr2
pla
rts
; if there's no error, then lets read the block into memory
; because Applewin is picky about memory management, here's what I did:
; on read, hd_nextbyte = buffer[0], therefore we'll read that byte 256 times (in which
; the emulated code increments the buffer by 1 on each read) to (memblock),y
; increment memblock+1 and read the secod 256 bytes via hd_nextbyte.
;
; if I could figure out how to consistantly get applewin to update it's memory regions all
; this code can be moved into the emulation code (although, this is how I'd build the hardware
; anyway...)
sread
tya
pha
ldy #0
loop1
lda hd_nextbyte
sta (memblock),y
iny
bne loop1
inc memblock+1
ldy #0
loop2
lda hd_nextbyte
sta (memblock),y
iny
bne loop2
pla
tay
rts
; $CsFE = status bits (BAP p7-14)
; 7 = medium is removable
; 6 = device is interruptable
; 5-4 = number of volumes (0..3 means 1..4)
; 3 = device supports Format call
; 2 = device can be written to
; 1 = device can be read from (must be 1)
; 0 = device status can be read (must be 1)
; $C7 = Removable, Interruptable, #Volumes=1, Supports write/read/status
; $D7 = Removable, Interruptable, #Volumes=2, Supports write/read/status
; datablock. This starts near the end of the firmware (at offset $FC)
;; data
*= $c7fc ; org $c7fc
.word $7fff ; how many blocks are on the device.
.byte $D7 ; specifics about the device (number of drives, read/write/format capability, etc)
.byte <cmdproc ; entry point offset for Prodos
.end