mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-12-26 11:30:12 +00:00
226 lines
4.3 KiB
ArmAsm
226 lines
4.3 KiB
ArmAsm
;fast bootable seek/read, slot 6 version
|
|
;copyright (c) Peter Ferrie 2011-2012
|
|
|
|
; Translated to ca64 by Vince Weaver
|
|
|
|
chksum = 0 ;otherwise safer but 12 bytes larger
|
|
secldr2 = $0e ;14th sector is fastest when loaded from bootsector but can be any of them
|
|
seekback = 0 ;set to 1 to enable seek backwards
|
|
|
|
adrlo = $26 ;constant from boot prom
|
|
adrhi = $27 ;constant from boot prom
|
|
slot = $2b ;constant from boot prom
|
|
tmpsec = $3c ;constant from boot prom
|
|
tmpadr = $41
|
|
partial2 = $f9 ;copy of partial1
|
|
partial1 = $fa ;sectors to read from one track
|
|
total = $fb ;total sectors to read
|
|
step = $fc ;state for stepper motor
|
|
tmptrk = $fd ;temporary copy of current track
|
|
curtrk = $fe ;current track (must initialise before calling seek)
|
|
phase = $ff ;current phase for seek
|
|
addrtbl = $50 ;requires 16 bytes
|
|
nibtbl = $2d6 ;constant from boot prom
|
|
bit2tbl = $200 ;hard-coded (uses $2aa-$2ff)
|
|
|
|
maxsec = $10 ;sectors per track, usually 10 but 0b for Olympic Decathlon, 0c for Karateka
|
|
|
|
;this section is specific to bootsectors
|
|
;load second stage sector to $900, enabling track seek
|
|
; tax ;1 sector
|
|
; lda #secldr2
|
|
; ldy #9
|
|
; jsr seekread
|
|
jmp ldr2
|
|
;
|
|
|
|
seekread: stx total
|
|
sta addrtbl
|
|
sty tmpadr
|
|
calcpart: sec
|
|
lda #maxsec
|
|
sbc addrtbl
|
|
cmp total
|
|
bcs L1
|
|
tax
|
|
L1: stx partial1
|
|
stx partial2
|
|
callseek: jsr seek - 1 ;(seekret) disabled during boot, increment to enable
|
|
ldy addrtbl
|
|
ldx #$0f
|
|
lda #0
|
|
L2: sta addrtbl, x
|
|
dex
|
|
bpl L2
|
|
L3: lda tmpadr
|
|
ldx sectbl, y
|
|
sta addrtbl, x
|
|
inc tmpadr
|
|
iny
|
|
dec partial1
|
|
bne L3
|
|
|
|
read: ldx #0
|
|
read1:
|
|
L4: jsr readnib
|
|
L5: cmp #$d5
|
|
bne L4
|
|
jsr readnib
|
|
cmp #$aa
|
|
bne L5
|
|
tay ;we need Y=#$AA later
|
|
jsr readnib
|
|
eor #$ad ;zero A if match
|
|
beq check_mode
|
|
|
|
;if not #$AD, then #$96 is assumed
|
|
|
|
ldy #2 ;high 8 bits of bit2tbl
|
|
sty adrhi ;store 2-bits array at $2xx
|
|
L6: jsr readnib
|
|
rol ;set carry
|
|
sta tmpsec
|
|
jsr readnib
|
|
and tmpsec
|
|
dey
|
|
bpl L6
|
|
.if chksum
|
|
sta tmpsec
|
|
tay
|
|
ldx addrtbl, y
|
|
stx step
|
|
.else
|
|
tay
|
|
lda addrtbl, y
|
|
sta step
|
|
stx addrtbl, y
|
|
tax
|
|
.endif
|
|
bcs read1
|
|
check_mode: cpx #0 ;set carry if non-zero
|
|
beq read1
|
|
.byte $90
|
|
L7: clc
|
|
L8: ldx $c0ec
|
|
bpl L8
|
|
eor nibtbl, x
|
|
sta (adrlo), y ;$2xx initially, and then the real address
|
|
iny
|
|
bne L8
|
|
ldx step
|
|
stx adrhi ;set real address
|
|
bcs L7 ;carry is set on first pass, clear on second, loops one time
|
|
.if chksum
|
|
L9: ldx $c0ec
|
|
bpl L9
|
|
eor nibtbl, x
|
|
bne read
|
|
ldx tmpsec
|
|
sta addrtbl, x
|
|
.endif
|
|
L10: ldx #$a9
|
|
L11: inx
|
|
beq L10
|
|
lda (adrlo), y
|
|
lsr bit2tbl, x
|
|
rol
|
|
lsr bit2tbl, x
|
|
rol
|
|
sta (adrlo), y
|
|
iny
|
|
bne L11
|
|
dec total
|
|
dec partial2
|
|
bne read ;read all requested sectors in one track
|
|
ldx total
|
|
beq seekret
|
|
inc phase
|
|
inc phase ;update current track
|
|
jmp calcpart
|
|
|
|
sectbl: .byte 0, $0d, $0b, 9, 7, 5, 3, 1, $0e, $0c, $0a, 8, 6, 4, 2, $0f
|
|
|
|
readnib:
|
|
L12: lda $c0ec
|
|
bpl L12
|
|
seekret: rts ;hard-coded relative to seek
|
|
|
|
seek: lda #0
|
|
sta step
|
|
copy_cur: lda curtrk
|
|
sta tmptrk
|
|
sec
|
|
sbc phase
|
|
beq seekret
|
|
.if seekback
|
|
bcs L13
|
|
.endif
|
|
eor #$ff
|
|
inc curtrk
|
|
.if seekback
|
|
bcc L14
|
|
L13: adc #$fe
|
|
dec curtrk
|
|
L14:
|
|
.endif
|
|
cmp step
|
|
bcc L15
|
|
lda step
|
|
L15: cmp #8
|
|
bcs L16
|
|
tay
|
|
sec
|
|
L16: lda curtrk
|
|
ldx step1, y
|
|
bne L18
|
|
L17: clc
|
|
lda tmptrk
|
|
ldx step2, y
|
|
L18: stx tmpsec
|
|
and #3
|
|
rol
|
|
tax
|
|
sta $c0e0, x
|
|
L19: ldx #$13
|
|
L20: dex
|
|
bne L20
|
|
dec tmpsec
|
|
bne L19
|
|
lsr
|
|
bcs L17
|
|
inc step
|
|
bne copy_cur
|
|
|
|
step1: .byte 1, $30, $28, $24, $20, $1e, $1d, $1c
|
|
step2: .byte $70, $2c, $26, $22, $1f, $1e, $1d, $1c
|
|
|
|
newtrk = $36 ;track*2 for main stage
|
|
newnum = $80 ;number of sectors in main stage
|
|
newsec = 0 ;first sector in main stage
|
|
newadr = $40 ;load address for main stage
|
|
newstart = $4000 ;start address for main stage
|
|
|
|
ldr2: ;jmp ldr2
|
|
;replace with something like the following:
|
|
|
|
inc callseek + 1
|
|
|
|
lda #$50
|
|
sta curtrk
|
|
lda #0
|
|
sta phase
|
|
jsr seek
|
|
|
|
ldy #0
|
|
|
|
sty curtrk
|
|
lda #newtrk
|
|
sta phase
|
|
ldx #newnum
|
|
lda #newsec
|
|
ldy #newadr
|
|
jsr seekread
|
|
; jmp newstart
|
|
|
|
ldr3: jmp ldr3
|