mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-12-26 11:30:12 +00:00
364 lines
5.0 KiB
ArmAsm
364 lines
5.0 KiB
ArmAsm
; the following lives on sectors $0E and $0D
|
|
; why?
|
|
; request sector 2 and 4, and the interleave is
|
|
|
|
; beneath apple dos (3-23)
|
|
; Physical (firmware) : 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
|
|
; DOS33 mapping : 0, 7, 14, 6, 13, 5, 12, 4, 11, 3, 10, 2, 9, 1, 8, 15
|
|
|
|
|
|
; Beneath Apple DOS
|
|
; p86 (dos reference)
|
|
;
|
|
|
|
WAIT = $FCA8 ;; delay 1/2(26+27A+5A^2) us
|
|
|
|
.org $1000
|
|
|
|
code_begin:
|
|
|
|
.byte version
|
|
|
|
readnib:
|
|
slotpatch1: ; smc
|
|
lda $c0d1 ; gets set to C08C (Q6L) read
|
|
bpl readnib
|
|
rts
|
|
|
|
;fill address array for one track
|
|
seekread:
|
|
sty startsec+1
|
|
sta tmpadr+1
|
|
stx total+1
|
|
|
|
inittrk:
|
|
sec
|
|
lda #$10
|
|
sbc startsec+1
|
|
cmp total+1
|
|
bcs it_skip
|
|
|
|
tax
|
|
|
|
it_skip:
|
|
stx partial1
|
|
stx partial2
|
|
jsr seek
|
|
|
|
startsec:
|
|
ldy #$d1
|
|
|
|
tmpadr:
|
|
tmpadr_loop:
|
|
lda #$d1
|
|
sta addrtbl, y
|
|
inc tmpadr+1
|
|
iny
|
|
dec partial1
|
|
bne tmpadr_loop
|
|
|
|
;====================================
|
|
; read a sector
|
|
;====================================
|
|
; first address field
|
|
;====================================
|
|
; starts with $D5 $AA $96
|
|
; then XX YY volume
|
|
; then XX YY track
|
|
; then XX YY sector
|
|
; then XX YY checksum
|
|
; then ends with $DE $AA $EB
|
|
;====================================
|
|
; data field
|
|
;====================================
|
|
; starts with $D5 $AA $AD
|
|
; 342 bytes of data
|
|
; XX checksum
|
|
; ends with $DE $AA $EB
|
|
read:
|
|
|
|
outer_read:
|
|
jsr readnib
|
|
inner_read:
|
|
cmp #$d5 ; look for $D5 part of addr field
|
|
bne outer_read
|
|
|
|
jsr readnib ; look for $D5 $AA
|
|
cmp #$aa
|
|
bne inner_read
|
|
|
|
; look for $D5 $AA $AD
|
|
|
|
tay ; we need Y=#$AA later
|
|
jsr readnib
|
|
eor #$ad ; zero A if match
|
|
beq check_mode
|
|
|
|
; if not #$AD, then #$96 is assumed
|
|
; so in address field
|
|
|
|
ldy #2 ; volume, track, sector
|
|
another:
|
|
jsr readnib
|
|
rol ; set carry
|
|
sta sector+1
|
|
jsr readnib
|
|
and sector+1
|
|
dey
|
|
bpl another
|
|
|
|
tay
|
|
ldx addrtbl, Y ; fetch corresponding address
|
|
beq read ; done?
|
|
|
|
sta sector+1 ; store index for later
|
|
|
|
stx adrpatch1+2
|
|
stx adrpatch8+2
|
|
stx adrpatch2+2
|
|
stx adrpatch3+2
|
|
stx adrpatch5+2
|
|
stx adrpatch7+2
|
|
|
|
inx
|
|
stx adrpatch9+2
|
|
dex
|
|
|
|
dex
|
|
stx adrpatch4+2
|
|
stx adrpatch6+2
|
|
|
|
ldy #$fe
|
|
|
|
loop2:
|
|
adrpatch1:
|
|
lda $d102, Y
|
|
pha
|
|
iny
|
|
bne loop2
|
|
|
|
branch_read:
|
|
bcs read ; branch always
|
|
|
|
check_mode:
|
|
cpx #0
|
|
beq read ; loop if not expecting #$AD
|
|
|
|
loop33:
|
|
sta tmpval+1 ; zero rolling checksum
|
|
slotpatch2:
|
|
loop4:
|
|
ldx $c0d1
|
|
bpl loop4
|
|
lda preshift-$96, X
|
|
adrpatch2:
|
|
sta $d102, Y ; store 2-bit array
|
|
|
|
tmpval:
|
|
eor #$d1
|
|
iny
|
|
bne loop33
|
|
ldy #$aa
|
|
slotpatch3:
|
|
loop5:
|
|
ldx $c0d1
|
|
bpl loop5
|
|
eor preshift-$96, X
|
|
adrpatch3:
|
|
ldx $d102, Y ; bit2tbl
|
|
eor grouped+2, X ; first 86 nibbles use group bits 0-1
|
|
adrpatch4:
|
|
sta $d156, y
|
|
iny
|
|
bne loop5
|
|
and #$fc
|
|
ldy #$aa
|
|
slotpatch4:
|
|
loop6:
|
|
ldx $c0d1
|
|
bpl loop6
|
|
eor preshift-$96, X
|
|
adrpatch5:
|
|
ldx $d102, Y ; bit2tbl
|
|
eor grouped+1, X ; second 86 nibbles use group bits 2-3
|
|
adrpatch6:
|
|
sta $d1ac, Y
|
|
iny
|
|
bne loop6
|
|
and #$fc
|
|
ldx #$ac
|
|
slotpatch5:
|
|
loop7:
|
|
ldy $c0d1
|
|
bpl loop7
|
|
eor preshift-$96, Y
|
|
adrpatch7:
|
|
ldy $d100, X ; bit2tbl
|
|
eor grouped, Y ; last 84 nibbles use group bits 4-5
|
|
adrpatch8:
|
|
sta $d100, x
|
|
inx
|
|
bne loop7
|
|
and #$fc
|
|
slotpatch6:
|
|
loop8:
|
|
ldy $c0d1
|
|
bpl loop8
|
|
eor preshift-$96, Y
|
|
cmp #1 ; carry = !zero
|
|
ldy #1
|
|
loop9:
|
|
pla
|
|
adrpatch9:
|
|
sta $d100, Y
|
|
dey
|
|
bpl loop9
|
|
branch_read2:
|
|
bcs branch_read ; branch if checksum failure
|
|
|
|
sector:
|
|
ldy #$d1
|
|
txa
|
|
sta addrtbl, Y ; zero corresponding address
|
|
dec total+1
|
|
dec partial2 ; adjust remaining count
|
|
; (faster than looping over array)
|
|
sec
|
|
bne branch_read2 ; read all requested sectors in one track
|
|
|
|
sta startsec+1 ; this was missing from original code
|
|
; leading to trouble on wrap around
|
|
; it not starting at sector0
|
|
total:
|
|
ldx #$d1
|
|
beq driveoff
|
|
inc phase+1
|
|
inc phase+1 ; update current track
|
|
jmp inittrk
|
|
|
|
driveoff:
|
|
slotpatch7:
|
|
lda $c0d1
|
|
|
|
seekret:
|
|
rts
|
|
|
|
seek:
|
|
ldx #0
|
|
stx step+1
|
|
copy_cur:
|
|
curtrk:
|
|
lda #0
|
|
sta tmpval+1
|
|
sec
|
|
phase:
|
|
sbc #$d1
|
|
beq seekret
|
|
|
|
; if seek backwards
|
|
bcs sback
|
|
|
|
eor #$ff
|
|
inc curtrk+1
|
|
|
|
bcc ssback
|
|
sback:
|
|
adc #$fe
|
|
dec curtrk+1
|
|
ssback:
|
|
cmp step+1
|
|
bcc loop10
|
|
step:
|
|
lda #$d1
|
|
loop10:
|
|
cmp #8
|
|
bcs loop11
|
|
tay
|
|
sec
|
|
loop11:
|
|
lda curtrk+1
|
|
ldx step1, Y
|
|
bne loop12
|
|
loopmmm:
|
|
clc
|
|
lda tmpval+1
|
|
ldx step2, Y
|
|
loop12:
|
|
stx sector+1
|
|
and #3
|
|
rol
|
|
tax
|
|
slotpatch8:
|
|
sta $c0d1, X
|
|
loopmm:
|
|
ldx #$13
|
|
loopm:
|
|
dex
|
|
bne loopm
|
|
dec sector+1
|
|
bne loopmm
|
|
lsr
|
|
bcs loopmmm
|
|
inc step+1
|
|
bne copy_cur
|
|
|
|
step1: .byte 1, $30, $28, $24, $20, $1e, $1d, $1c
|
|
step2: .byte $70, $2c, $26, $22, $1f, $1e, $1d, $1c
|
|
addrtbl: .res 16
|
|
|
|
partial1: .byte $00
|
|
partial2: .byte $00
|
|
code_end:
|
|
|
|
|
|
|
|
;==========================
|
|
; enable drive motor
|
|
;==========================
|
|
|
|
driveon:
|
|
|
|
slotpatch9:
|
|
lda $c0d1
|
|
|
|
; wait 1s
|
|
|
|
ldx #6
|
|
wait_1s:
|
|
lda #255
|
|
jsr WAIT
|
|
dex
|
|
bne wait_1s
|
|
|
|
rts
|
|
|
|
load_new:
|
|
|
|
jsr driveon
|
|
|
|
lda load_track
|
|
asl ; track to start*2
|
|
sta phase+1
|
|
|
|
lda load_sector
|
|
tay ; sector to start
|
|
|
|
lda load_length ; length
|
|
tax
|
|
|
|
lda load_address ; address to load
|
|
|
|
jsr seekread
|
|
|
|
rts
|
|
|
|
load_address:
|
|
.byte $00
|
|
load_track:
|
|
.byte $00
|
|
load_sector:
|
|
.byte $00
|
|
load_length:
|
|
.byte $00
|
|
|