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megaload: it will never work
This commit is contained in:
Vince Weaver
parent
ec6b4b9f54
commit
343a990896
225
megademo/disk/megaload.s
Normal file
225
megademo/disk/megaload.s
Normal file
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@ -0,0 +1,225 @@
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;fast bootable seek/read, slot 6 version
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;copyright (c) Peter Ferrie 2011-2012
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; Translated to ca64 by Vince Weaver
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chksum = 0 ;otherwise safer but 12 bytes larger
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secldr2 = $0e ;14th sector is fastest when loaded from bootsector but can be any of them
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seekback = 0 ;set to 1 to enable seek backwards
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adrlo = $26 ;constant from boot prom
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adrhi = $27 ;constant from boot prom
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slot = $2b ;constant from boot prom
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tmpsec = $3c ;constant from boot prom
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tmpadr = $41
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partial2 = $f9 ;copy of partial1
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partial1 = $fa ;sectors to read from one track
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total = $fb ;total sectors to read
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step = $fc ;state for stepper motor
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tmptrk = $fd ;temporary copy of current track
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curtrk = $fe ;current track (must initialise before calling seek)
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phase = $ff ;current phase for seek
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addrtbl = $50 ;requires 16 bytes
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nibtbl = $2d6 ;constant from boot prom
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bit2tbl = $200 ;hard-coded (uses $2aa-$2ff)
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maxsec = $10 ;sectors per track, usually 10 but 0b for Olympic Decathlon, 0c for Karateka
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;this section is specific to bootsectors
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;load second stage sector to $900, enabling track seek
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; tax ;1 sector
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; lda #secldr2
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; ldy #9
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; jsr seekread
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jmp ldr2
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;
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seekread: stx total
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sta addrtbl
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sty tmpadr
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calcpart: sec
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lda #maxsec
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sbc addrtbl
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cmp total
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bcs L1
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tax
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L1: stx partial1
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stx partial2
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callseek: jsr seek - 1 ;(seekret) disabled during boot, increment to enable
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ldy addrtbl
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ldx #$0f
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lda #0
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L2: sta addrtbl, x
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dex
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bpl L2
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L3: lda tmpadr
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ldx sectbl, y
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sta addrtbl, x
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inc tmpadr
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iny
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dec partial1
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bne L3
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read: ldx #0
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read1:
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L4: jsr readnib
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L5: cmp #$d5
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bne L4
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jsr readnib
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cmp #$aa
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bne L5
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tay ;we need Y=#$AA later
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jsr readnib
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eor #$ad ;zero A if match
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beq check_mode
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;if not #$AD, then #$96 is assumed
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ldy #2 ;high 8 bits of bit2tbl
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sty adrhi ;store 2-bits array at $2xx
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L6: jsr readnib
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rol ;set carry
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sta tmpsec
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jsr readnib
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and tmpsec
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dey
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bpl L6
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.if chksum
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sta tmpsec
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tay
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ldx addrtbl, y
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stx step
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.else
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tay
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lda addrtbl, y
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sta step
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stx addrtbl, y
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tax
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.endif
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bcs read1
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check_mode: cpx #0 ;set carry if non-zero
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beq read1
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.byte $90
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L7: clc
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L8: ldx $c0ec
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bpl L8
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eor nibtbl, x
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sta (adrlo), y ;$2xx initially, and then the real address
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iny
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bne L8
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ldx step
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stx adrhi ;set real address
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bcs L7 ;carry is set on first pass, clear on second, loops one time
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.if chksum
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L9: ldx $c0ec
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bpl L9
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eor nibtbl, x
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bne read
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ldx tmpsec
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sta addrtbl, x
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.endif
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L10: ldx #$a9
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L11: inx
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beq L10
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lda (adrlo), y
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lsr bit2tbl, x
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rol
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lsr bit2tbl, x
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rol
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sta (adrlo), y
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iny
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bne L11
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dec total
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dec partial2
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bne read ;read all requested sectors in one track
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ldx total
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beq seekret
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inc phase
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inc phase ;update current track
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jmp calcpart
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sectbl: .byte 0, $0d, $0b, 9, 7, 5, 3, 1, $0e, $0c, $0a, 8, 6, 4, 2, $0f
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readnib:
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L12: lda $c0ec
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bpl L12
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seekret: rts ;hard-coded relative to seek
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seek: lda #0
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sta step
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copy_cur: lda curtrk
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sta tmptrk
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sec
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sbc phase
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beq seekret
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.if seekback
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bcs L13
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.endif
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eor #$ff
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inc curtrk
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.if seekback
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bcc L14
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L13: adc #$fe
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dec curtrk
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L14:
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.endif
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cmp step
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bcc L15
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lda step
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L15: cmp #8
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bcs L16
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tay
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sec
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L16: lda curtrk
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ldx step1, y
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bne L18
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L17: clc
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lda tmptrk
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ldx step2, y
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L18: stx tmpsec
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and #3
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rol
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tax
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sta $c0e0, x
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L19: ldx #$13
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L20: dex
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bne L20
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dec tmpsec
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bne L19
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lsr
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bcs L17
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inc step
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bne copy_cur
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step1: .byte 1, $30, $28, $24, $20, $1e, $1d, $1c
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step2: .byte $70, $2c, $26, $22, $1f, $1e, $1d, $1c
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newtrk = $36 ;track*2 for main stage
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newnum = $80 ;number of sectors in main stage
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newsec = 0 ;first sector in main stage
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newadr = $40 ;load address for main stage
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newstart = $4000 ;start address for main stage
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ldr2: ;jmp ldr2
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;replace with something like the following:
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inc callseek + 1
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lda #$50
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sta curtrk
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lda #0
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sta phase
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jsr seek
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ldy #0
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sty curtrk
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lda #newtrk
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sta phase
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ldx #newnum
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lda #newsec
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ldy #newadr
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jsr seekread
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; jmp newstart
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ldr3: jmp ldr3
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@ -20,7 +20,8 @@
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sizelo = $44
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sizehi = $45
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secsize = $46
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tempy = $fa
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TEMPX = $f9
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TEMPY = $fa
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namlo = $fb
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namhi = $fc
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step = $fd ;state for stepper motor
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@ -212,7 +213,7 @@ L6:
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inc adrhi
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iny
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iny
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bne eadnext
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bne readnext
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; save current address for after t/s read
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@ -365,18 +366,19 @@ L21:
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; Stepper motor delay
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;=====================
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stepdelay:
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phx
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stx TEMPX ; was **phx**
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and #3
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rol
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tax
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lda $c0e0, x
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pla
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lda TEMPX ; was **pla**
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L22:
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ldx #$13
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L23:
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dex
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bne L23
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dec
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sec
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sbc #1 ; was **dec**
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bne L22
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seekret:
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rts
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@ -399,7 +401,7 @@ copy_cur:
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eor #$ff
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inc curtrk
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bcc L25
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l24:
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L24:
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sec
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sbc #1 ; *** WAS *** dec
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dec curtrk
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@ -1,215 +1,464 @@
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;fast bootable seek/read, slot 6 version
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;copyright (c) Peter Ferrie 2011-2012
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;read any file slot 6 version
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;copyright (c) Peter Ferrie 2013
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;!cpu 65c02
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;!to "trk",plain
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;*=$800
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; Translated to ca64 by Vince Weaver
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adrlo = $26 ;constant from boot prom
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adrhi = $27 ;constant from boot prom
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tmpsec = $3c ;constant from boot prom
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reqsec = $3d ;constant from boot prom
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A1L = $3c ;constant from ROM
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A1H = $3d ;constant from ROM
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A2L = $3e ;constant from ROM
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A2H = $3f ;constant from ROM
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curtrk = $40
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niblo = $41
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nibhi = $42
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A4L = $42 ;constant from ROM
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A4H = $43 ;constant from ROM
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sizelo = $44
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sizehi = $45
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secsize = $46
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TEMPX = $f9
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TEMPY = $fa
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namlo = $fb
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namhi = $fc
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step = $fd ;state for stepper motor
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tmptrk = $fe ;temporary copy of current track
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phase = $ff ;current phase for seek
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reloc = $bc00
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dirbuf = $bf00
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MOVE = $fe2c
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chksum = 0 ;otherwise safer but 12 bytes larger
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secldr2 = $0e ;14th sector is fastest when loaded from bootsector but can be any of them
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seekback = 0 ;set to 1 to enable seek backwards
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start:
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jsr init ;one-time call to unhook DOS
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;open and read a file
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lda #<file_to_read
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sta namlo
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lda #>file_to_read
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sta namhi
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jsr opendir ;open and read entire file into memory at its load address
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adrlo = $26 ;constant from boot prom
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adrhi = $27 ;constant from boot prom
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slot = $2b ;constant from boot prom
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tmpsec = $3c ;constant from boot prom
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tmpadr = $41
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partial2 = $f9 ;copy of partial1
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partial1 = $fa ;sectors to read from one track
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total = $fb ;total sectors to read
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step = $fc ;state for stepper motor
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tmptrk = $fd ;temporary copy of current track
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curtrk = $fe ;current track (must initialise before calling seek)
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phase = $ff ;current phase for seek
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addrtbl = $50 ;requires 16 bytes
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nibtbl = $2d6 ;constant from boot prom
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bit2tbl = $200 ;hard-coded (uses $2aa-$2ff)
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blah: jmp blah
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maxsec = $10 ;sectors per track, usually 10 but 0b for Olympic Decathlon, 0c for Karateka
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; format of request name is 30-character Apple text:
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;e.g. !scrxor $80, "MYFILE "
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file_to_read: ;.byte "MYFILE "
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.byte 'M'|$80,'E'|$80,'G'|$80,'A'|$80,'D'|$80,'E'|$80,'M'|$80,'O'|$80
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.byte $A0,$A0,$A0,$A0,$A0,$A0,$A0,$A0
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.byte $A0,$A0,$A0,$A0,$A0,$A0,$A0,$A0
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.byte $A0,$A0,$A0,$A0,$A0,$A0
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;this section is specific to bootsectors
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;load second stage sector to $900, enabling track seek
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tax ;1 sector
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lda #secldr2
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ldy #9
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jsr seekread
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jmp ldr2
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;
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seekread: stx total
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sta addrtbl
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sty tmpadr
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calcpart: sec
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lda #maxsec
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sbc addrtbl
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cmp total
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bcs L1
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tax
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L1: stx partial1
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stx partial2
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callseek: jsr seek - 1 ;(seekret) disabled during boot, increment to enable
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ldy addrtbl
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ldx #$0f
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lda #0
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L2: sta addrtbl, x
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dex
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bpl L2
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L3: lda tmpadr
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ldx sectbl, y
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sta addrtbl, x
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inc tmpadr
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iny
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dec partial1
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bne L3
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;unhook DOS and build nibble table
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read: ldx #0
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read1:
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L4: jsr readnib
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L5: cmp #$d5
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bne L4
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jsr readnib
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cmp #$aa
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bne L5
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tay ;we need Y=#$AA later
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jsr readnib
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eor #$ad ;zero A if match
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beq check_mode
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init:
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jsr $fe93 ; clear COUT
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jsr $fe89 ; clear KEYIN
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; lda #<unreloc
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; sta A1L
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; lda #>unreloc
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; sta A1H
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; lda #<(unreloc+(codeend-opendir)-1)
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; sta A2L
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; lda #>(unreloc+(codeend-opendir)-1)
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; sta A2H
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; ldy #0
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; sty A4L
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; lda #>reloc
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; sta A4H
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; jsr MOVE ; move mem from A1-A2 to location A4
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;if not #$AD, then #$96 is assumed
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ldx #3
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L1: stx $3c
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txa
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asl
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bit $3c
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beq L3
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ora $3c
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eor #$ff
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and #$7e
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L2: bcs L3
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lsr
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bne L2
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tya
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sta nibtbl, x
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iny
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L3: inx
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bpl L1
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ldy #2 ;high 8 bits of bit2tbl
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sty adrhi ;store 2-bits array at $2xx
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L6: jsr readnib
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rol ;set carry
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sta tmpsec
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jsr readnib
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and tmpsec
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dey
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bpl L6
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.if chksum
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sta tmpsec
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tay
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ldx addrtbl, y
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stx step
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.else
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tay
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lda addrtbl, y
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sta step
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stx addrtbl, y
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tax
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.endif
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bcs read1
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check_mode: cpx #0 ;set carry if non-zero
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beq read1
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.byte $90
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L7: clc
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L8: ldx $c0ec
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bpl L8
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eor nibtbl, x
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sta (adrlo), y ;$2xx initially, and then the real address
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iny
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bne L8
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ldx step
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stx adrhi ;set real address
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bcs L7 ;carry is set on first pass, clear on second, loops one time
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.if chksum
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L9: ldx $c0ec
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bpl L9
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eor nibtbl, x
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bne read
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ldx tmpsec
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sta addrtbl, x
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.endif
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L10: ldx #$a9
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L11: inx
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beq L10
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lda (adrlo), y
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lsr bit2tbl, x
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rol
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lsr bit2tbl, x
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rol
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sta (adrlo), y
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iny
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bne L11
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dec total
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dec partial2
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bne read ;read all requested sectors in one track
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ldx total
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beq seekret
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inc phase
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inc phase ;update current track
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jmp calcpart
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rts
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sectbl: .byte 0, $0d, $0b, 9, 7, 5, 3, 1, $0e, $0c, $0a, 8, 6, 4, 2, $0f
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unreloc:
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;!pseudopc reloc {
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readnib:
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L12: lda $c0ec
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bpl L12
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seekret: rts ;hard-coded relative to seek
|
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;turn on drive and read volume table of contents
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seek: lda #0
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sta step
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copy_cur: lda curtrk
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sta tmptrk
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sec
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sbc phase
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beq seekret
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.if seekback
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bcs L13
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.endif
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eor #$ff
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inc curtrk
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.if seekback
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bcc L14
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L13: adc #$fe
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dec curtrk
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opendir:
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lda $c0e9
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ldx #0
|
||||
stx adrlo
|
||||
stx secsize
|
||||
lda #$11
|
||||
jsr readdirsec
|
||||
firstent:
|
||||
lda dirbuf+1
|
||||
|
||||
;lock if entry not found
|
||||
|
||||
beq *
|
||||
|
||||
;read directory sector
|
||||
|
||||
ldx dirbuf+2
|
||||
jsr seekread1
|
||||
ldy #7 ;number of directory entries in a sector
|
||||
ldx #$2b ;offset of filename in directory entry
|
||||
nextent:
|
||||
tya
|
||||
pha ; was **phy**
|
||||
txa
|
||||
pha ; was **phx**
|
||||
ldy #$1d
|
||||
|
||||
; match name backwards (slower but smaller)
|
||||
|
||||
L4:
|
||||
lda (namlo), y
|
||||
cmp dirbuf, x
|
||||
beq foundname
|
||||
pla
|
||||
|
||||
; move to next directory in this block, if possible
|
||||
|
||||
clc
|
||||
adc #$23
|
||||
tax
|
||||
pla
|
||||
tay ; was **ply**
|
||||
dey
|
||||
bne nextent
|
||||
beq firstent ; was **bra**
|
||||
|
||||
foundname:
|
||||
dex
|
||||
dey
|
||||
bpl L4
|
||||
pla
|
||||
tay ; was **ply**
|
||||
pla
|
||||
|
||||
; read track/sector list
|
||||
|
||||
lda dirbuf-32, y
|
||||
ldx dirbuf-31, y
|
||||
jsr seekread1
|
||||
|
||||
; read load offset and length info only, initially
|
||||
|
||||
lda #<filbuf
|
||||
sta adrlo
|
||||
lda #4
|
||||
sta secsize
|
||||
lda dirbuf+12
|
||||
ldx dirbuf+13
|
||||
ldy #>filbuf
|
||||
jsr seekread
|
||||
|
||||
; reduce load offset by 4, to account for offset and length
|
||||
|
||||
sec
|
||||
lda filbuf
|
||||
sbc #4
|
||||
sta adrlo
|
||||
lda filbuf+1
|
||||
sbc #0
|
||||
sta adrhi
|
||||
|
||||
; save on stack bytes that will be overwritten by extra read
|
||||
|
||||
ldy #3
|
||||
L5:
|
||||
lda (adrlo), y
|
||||
pha
|
||||
dey
|
||||
bpl L5
|
||||
|
||||
lda adrhi
|
||||
pha
|
||||
lda adrlo
|
||||
pha
|
||||
|
||||
; increase load size by 4, to account for offst and length
|
||||
|
||||
lda filbuf+2
|
||||
adc #3
|
||||
sta sizelo
|
||||
sta secsize
|
||||
lda filbuf+3
|
||||
adc #0
|
||||
sta sizehi
|
||||
beq readfirst
|
||||
ldy #0 ; was **stz secsize**
|
||||
sty secsize
|
||||
|
||||
readfirst:
|
||||
ldy #$0c
|
||||
|
||||
; read a file sector
|
||||
|
||||
readnext:
|
||||
lda dirbuf, y
|
||||
ldx dirbuf+1, y
|
||||
sty TEMPY ; ** was phy **
|
||||
jsr seekread1
|
||||
ldy TEMPY ; ** was ply **
|
||||
|
||||
; if low count is non-zero then we are done
|
||||
; (can happen only for partial last block)
|
||||
|
||||
lda secsize
|
||||
bne readdone
|
||||
|
||||
; continue if more than $100 bytes left
|
||||
|
||||
dec sizehi
|
||||
bne L6
|
||||
|
||||
;set read size to min(length, $100)
|
||||
|
||||
lda sizelo
|
||||
beq readdone
|
||||
sta secsize
|
||||
L6:
|
||||
inc adrhi
|
||||
iny
|
||||
iny
|
||||
bne readnext
|
||||
|
||||
; save current address for after t/s read
|
||||
|
||||
lda adrhi
|
||||
pha
|
||||
lda adrlo
|
||||
pha
|
||||
lda #0
|
||||
sta adrlo ; was **stz adrlo**
|
||||
|
||||
; read next track/sector sector
|
||||
|
||||
lda dirbuf+1
|
||||
ldx dirbuf+2
|
||||
jsr readdirsec
|
||||
clc
|
||||
|
||||
; restore current address
|
||||
readdone:
|
||||
pla
|
||||
sta adrhi
|
||||
pla
|
||||
sta adrlo
|
||||
bcc readfirst
|
||||
|
||||
lda $c0e8
|
||||
|
||||
; restore from stack bytes that were overwritten by extra read
|
||||
|
||||
ldx #3
|
||||
ldy #0
|
||||
L7:
|
||||
pla
|
||||
sta (adrlo), y
|
||||
iny
|
||||
dex
|
||||
bpl L7
|
||||
rts
|
||||
|
||||
readdirsec:
|
||||
ldy #>dirbuf
|
||||
seekread:
|
||||
sty adrhi
|
||||
seekread1:
|
||||
sta phase
|
||||
lda sectbl, x
|
||||
sta reqsec
|
||||
jsr readadr
|
||||
|
||||
; if track does not match, then seek
|
||||
|
||||
lda curtrk
|
||||
cmp phase
|
||||
beq checksec
|
||||
jsr seek
|
||||
|
||||
; [re-]read sector
|
||||
|
||||
L8:
|
||||
jsr readadr
|
||||
checksec:
|
||||
cmp reqsec
|
||||
bne L8
|
||||
|
||||
; read sector data
|
||||
|
||||
readdata:
|
||||
ldy $c0ec
|
||||
bpl readdata
|
||||
L9:
|
||||
cpy #$d5
|
||||
bne readdata
|
||||
L10:
|
||||
ldy $c0ec
|
||||
bpl L10
|
||||
cpy #$aa ;we need Y=#$AA later
|
||||
bne L9
|
||||
L11:
|
||||
lda $c0ec
|
||||
bpl L11
|
||||
eor #$ad ;zero A if match
|
||||
bne * ;lock if read failure
|
||||
L12:
|
||||
ldx $c0ec
|
||||
bpl L12
|
||||
eor nibtbl-$80, x
|
||||
sta bit2tbl-$aa, y
|
||||
iny
|
||||
bne L12
|
||||
L13:
|
||||
ldx $c0ec
|
||||
bpl L13
|
||||
eor nibtbl-$80, x
|
||||
sta (adrlo), y ;the real address
|
||||
iny
|
||||
cpy secsize
|
||||
bne L13
|
||||
ldy #0
|
||||
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 #$13
|
||||
L20: dex
|
||||
bne L20
|
||||
dec tmpsec
|
||||
bne L19
|
||||
lsr
|
||||
bcs L17
|
||||
inc step
|
||||
bne copy_cur
|
||||
ldx #$a9
|
||||
L15:
|
||||
inx
|
||||
beq L14
|
||||
lda (adrlo), y
|
||||
lsr bit2tbl-$aa, x
|
||||
rol
|
||||
lsr bit2tbl-$aa, x
|
||||
rol
|
||||
sta (adrlo), y
|
||||
iny
|
||||
cpy secsize
|
||||
bne L15
|
||||
rts
|
||||
|
||||
step1: .byte 1, $30, $28, $24, $20, $1e, $1d, $1c
|
||||
step2: .byte $70, $2c, $26, $22, $1f, $1e, $1d, $1c
|
||||
;no tricks here, just the regular stuff
|
||||
|
||||
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
|
||||
readadr:
|
||||
lda $c0ec
|
||||
bpl readadr
|
||||
L16:
|
||||
cmp #$d5
|
||||
bne readadr
|
||||
L17:
|
||||
lda $c0ec
|
||||
bpl L17
|
||||
cmp #$aa
|
||||
bne L16
|
||||
L18:
|
||||
lda $c0ec
|
||||
bpl L18
|
||||
cmp #$96
|
||||
bne L16
|
||||
ldy #3
|
||||
L19:
|
||||
sta curtrk
|
||||
L20:
|
||||
lda $c0ec
|
||||
bpl L20
|
||||
rol
|
||||
sta tmpsec
|
||||
L21:
|
||||
lda $c0ec
|
||||
bpl L21
|
||||
and tmpsec
|
||||
dey
|
||||
bne L19
|
||||
rts
|
||||
|
||||
ldr2: ;jmp ldr2
|
||||
;replace with something like the following:
|
||||
inc callseek + 1
|
||||
sty curtrk
|
||||
lda #newtrk
|
||||
sta phase
|
||||
ldx #newnum
|
||||
lda #newsec
|
||||
ldy #newadr
|
||||
jsr seekread
|
||||
; jmp newstart
|
||||
;=====================
|
||||
; Stepper motor delay
|
||||
;=====================
|
||||
stepdelay:
|
||||
stx TEMPX ; was **phx**
|
||||
and #3
|
||||
rol
|
||||
tax
|
||||
lda $c0e0, x
|
||||
lda TEMPX ; was **pla**
|
||||
L22:
|
||||
ldx #$13
|
||||
L23:
|
||||
dex
|
||||
bne L23
|
||||
sec
|
||||
sbc #1 ; was **dec**
|
||||
bne L22
|
||||
seekret:
|
||||
rts
|
||||
|
||||
ldr3: jmp ldr3
|
||||
;================
|
||||
; SEEK
|
||||
;================
|
||||
seek:
|
||||
asl curtrk
|
||||
lda #0
|
||||
sta step ; *** WAS *** stz step
|
||||
asl phase
|
||||
copy_cur:
|
||||
lda curtrk
|
||||
sta tmptrk
|
||||
sec
|
||||
sbc phase
|
||||
beq seekret
|
||||
bcs L24
|
||||
eor #$ff
|
||||
inc curtrk
|
||||
bcc L25
|
||||
L24:
|
||||
sec
|
||||
sbc #1 ; *** WAS *** dec
|
||||
dec curtrk
|
||||
L25:
|
||||
cmp step
|
||||
bcc L26
|
||||
lda step
|
||||
L26:
|
||||
cmp #8
|
||||
bcs L27
|
||||
tay
|
||||
sec
|
||||
L27:
|
||||
lda curtrk
|
||||
ldx step1, y
|
||||
jsr stepdelay
|
||||
lda tmptrk
|
||||
ldx step2, y
|
||||
jsr stepdelay
|
||||
inc step
|
||||
bne copy_cur
|
||||
|
||||
step1: .byte $01, $30, $28, $24, $20, $1e, $1d, $1c
|
||||
step2: .byte $70, $2c, $26, $22, $1f, $1e, $1d, $1c
|
||||
|
||||
sectbl: .byte 0, $0d, $0b, 9, 7, 5, 3, 1, $0e, $0c, $0a, 8, 6, 4, 2, $0f
|
||||
|
||||
codeend = *
|
||||
|
||||
nibtbl = *
|
||||
bit2tbl = nibtbl+128
|
||||
filbuf = bit2tbl+86
|
||||
dataend = filbuf+4
|
||||
;hack to error out when code is too large for current address
|
||||
;!if ((dirbuf-(dataend-opendir))&$ff00)<reloc {
|
||||
;1=1
|
||||
;}
|
||||
;}
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user