mirror of
https://github.com/deater/dos33fsprogs.git
synced 2025-01-14 13:33:48 +00:00
megaload: more messing with trying to get loader going
This commit is contained in:
Vince Weaver
parent
bb4a67e9d2
commit
f23af9698b
@ -10,7 +10,7 @@ all: megademo.dsk
|
||||
megademo.dsk: MEGADEMO MEGALOAD
|
||||
$(DOS33) -y megademo.dsk BSAVE -a 0x4000 MEGADEMO
|
||||
$(DOS33) -y megademo.dsk BSAVE -a 0x800 MEGALOAD
|
||||
$(DOS33) -y megademo.dsk RAWWRITE -t 27 -s 0 MEGADEMO MEGA2
|
||||
# $(DOS33) -y megademo.dsk RAWWRITE -t 27 -s 0 MEGADEMO MEGA2
|
||||
# $(DOS33) -y megademo.dsk BSAVE -a 0x4000 D_HGRC.BIN
|
||||
# $(DOS33) -y megademo.dsk BSAVE -a 0x4000 FS_HGRC.BIN
|
||||
# $(DOS33) -y megademo.dsk BSAVE -a 0x2000 C64C.BIN
|
||||
|
||||
@ -32,6 +32,7 @@
|
||||
MOVE = $fe2c
|
||||
|
||||
start:
|
||||
; jmp start
|
||||
jsr init ;one-time call to unhook DOS
|
||||
;open and read a file
|
||||
lda #<file_to_read
|
||||
@ -64,50 +65,57 @@ init:
|
||||
; sta A2L
|
||||
; lda #>(unreloc+(codeend-opendir)-1)
|
||||
; sta A2H
|
||||
; ldy #0
|
||||
ldy #0
|
||||
; sty A4L
|
||||
; lda #>reloc
|
||||
; sta A4H
|
||||
; jsr MOVE ; move mem from A1-A2 to location A4
|
||||
|
||||
; Create nibble table?
|
||||
ldx #3
|
||||
L1: stx $3c
|
||||
txa
|
||||
asl
|
||||
bit $3c
|
||||
beq L3
|
||||
ora $3c
|
||||
eor #$ff
|
||||
and #$7e
|
||||
L2: bcs L3
|
||||
lsr
|
||||
bne L2
|
||||
tya
|
||||
sta nibtbl, x
|
||||
iny
|
||||
L3: inx
|
||||
bpl L1
|
||||
L1: stx $3c ; store tempx (3?)
|
||||
txa ; a=x (a=3)
|
||||
asl ; a*=2 (a=6)
|
||||
bit $3c ; a&tempx, set N/V (a=6)
|
||||
beq L3 ; if 0, skip to L3
|
||||
ora $3c ; a|=tempx (a=7)
|
||||
eor #$ff ; a=~a (a=f8)
|
||||
and #$7e ; a&=0x7e 0111 1110 (a=78)
|
||||
L2: bcs L3 ; this set way back at asl??
|
||||
lsr ; a>>1 a=3c c=0
|
||||
; a=1e c=0
|
||||
; a=0f c=0
|
||||
; a=07 c=1
|
||||
bne L2 ; if a!=0 goto l2
|
||||
tya ; if a==0, a=y
|
||||
sta nibtbl, x ; write out to table
|
||||
iny ; increment y
|
||||
L3: inx ; increment x x=4, a=0f
|
||||
bpl L1 ; loop while high bit not set
|
||||
|
||||
rts
|
||||
|
||||
.align $100
|
||||
unreloc:
|
||||
;!pseudopc reloc {
|
||||
|
||||
;turn on drive and read volume table of contents
|
||||
|
||||
opendir:
|
||||
lda $c0e9
|
||||
lda $c0e9 ; turn slot#6 drive on
|
||||
ldx #0
|
||||
stx adrlo
|
||||
stx secsize
|
||||
lda #$11
|
||||
stx adrlo ; zero out adrlo
|
||||
stx secsize ; zero out secsize
|
||||
lda #$11 ; a=$11 (VTOC?)
|
||||
jsr readdirsec
|
||||
firstent:
|
||||
jmp firstent
|
||||
|
||||
lda dirbuf+1
|
||||
|
||||
;lock if entry not found
|
||||
|
||||
beq *
|
||||
entry_not_found:
|
||||
beq entry_not_found
|
||||
|
||||
;read directory sector
|
||||
|
||||
@ -275,6 +283,12 @@ L7:
|
||||
bpl L7
|
||||
rts
|
||||
|
||||
|
||||
;======================
|
||||
; readdirsec
|
||||
;======================
|
||||
; a = track?
|
||||
; x = sector?
|
||||
readdirsec:
|
||||
ldy #>dirbuf
|
||||
seekread:
|
||||
@ -289,47 +303,55 @@ seekread1:
|
||||
|
||||
lda curtrk
|
||||
cmp phase
|
||||
beq checksec
|
||||
beq repeat_until_right_sector
|
||||
jsr seek
|
||||
|
||||
; [re-]read sector
|
||||
|
||||
L8:
|
||||
re_read_addr:
|
||||
jsr readadr
|
||||
checksec:
|
||||
cmp reqsec
|
||||
bne L8
|
||||
|
||||
repeat_until_right_sector:
|
||||
cmp reqsec
|
||||
bne re_read_addr
|
||||
|
||||
blah2: jmp blah2
|
||||
|
||||
|
||||
|
||||
;==========================
|
||||
; read sector data
|
||||
;==========================
|
||||
;
|
||||
|
||||
readdata:
|
||||
ldy $c0ec
|
||||
ldy $c0ec ; read data until valid
|
||||
bpl readdata
|
||||
L9:
|
||||
cpy #$d5
|
||||
find_D5:
|
||||
cpy #$d5 ; if not D5, repeat
|
||||
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
|
||||
find_AA:
|
||||
ldy $c0ec ; read data until valid, should be AA
|
||||
bpl find_AA
|
||||
cpy #$aa ; we need Y=#$AA later
|
||||
bne find_D5
|
||||
find_AD:
|
||||
lda $c0ec ; read data until high bit set (valid)
|
||||
bpl find_AD
|
||||
eor #$ad ; should match $ad
|
||||
bne * ; lock if didn't find $ad (failure)
|
||||
L12:
|
||||
ldx $c0ec
|
||||
ldx $c0ec ; read data until high bit set (valid)
|
||||
bpl L12
|
||||
eor nibtbl-$80, x
|
||||
sta bit2tbl-$aa, y
|
||||
iny
|
||||
bne L12
|
||||
L13:
|
||||
ldx $c0ec
|
||||
ldx $c0ec ; read data until high bit set (valid)
|
||||
bpl L13
|
||||
eor nibtbl-$80, x
|
||||
sta (adrlo), y ;the real address
|
||||
sta (adrlo), y ; the real address
|
||||
iny
|
||||
cpy secsize
|
||||
bne L13
|
||||
@ -350,39 +372,50 @@ L15:
|
||||
bne L15
|
||||
rts
|
||||
|
||||
;no tricks here, just the regular stuff
|
||||
; no tricks here, just the regular stuff
|
||||
|
||||
;=================
|
||||
; readadr -- read address field
|
||||
;=================
|
||||
; Find address field, put track in cutrk, sector in tmpsec
|
||||
readadr:
|
||||
lda $c0ec
|
||||
lda $c0ec ; read data until we find a $D5
|
||||
bpl readadr
|
||||
L16:
|
||||
adr_d5:
|
||||
cmp #$d5
|
||||
bne readadr
|
||||
L17:
|
||||
lda $c0ec
|
||||
bpl L17
|
||||
|
||||
adr_aa:
|
||||
lda $c0ec ; read data until we find a $AA
|
||||
bpl adr_aa
|
||||
cmp #$aa
|
||||
bne L16
|
||||
L18:
|
||||
lda $c0ec
|
||||
bpl L18
|
||||
bne adr_d5
|
||||
|
||||
adr_96:
|
||||
lda $c0ec ; read data until we find a $96
|
||||
bpl adr_96
|
||||
cmp #$96
|
||||
bne L16
|
||||
ldy #3
|
||||
L19:
|
||||
sta curtrk
|
||||
bne adr_d5
|
||||
|
||||
ldy #3 ; three?
|
||||
; first read volume/volume
|
||||
; then track/track
|
||||
; then sector/sector?
|
||||
adr_read_two_bytes:
|
||||
sta curtrk ; store out current track
|
||||
L20:
|
||||
lda $c0ec
|
||||
bpl L20
|
||||
rol
|
||||
sta tmpsec
|
||||
lda $c0ec ; read until full value
|
||||
bpl L20
|
||||
rol
|
||||
sta tmpsec
|
||||
L21:
|
||||
lda $c0ec
|
||||
bpl L21
|
||||
lda $c0ec ; read until full value
|
||||
bpl L21 ; sector value is (v1<<1)&v2????
|
||||
and tmpsec
|
||||
dey
|
||||
bne L19
|
||||
rts
|
||||
dey ; loop 3 times
|
||||
bne adr_read_two_bytes
|
||||
|
||||
rts ; return
|
||||
|
||||
;=====================
|
||||
; Stepper motor delay
|
||||
@ -408,24 +441,27 @@ seekret:
|
||||
;================
|
||||
; SEEK
|
||||
;================
|
||||
; current track in curtrk
|
||||
; desired track in phase
|
||||
seek:
|
||||
asl curtrk
|
||||
lda #0
|
||||
sta step ; *** WAS *** stz step
|
||||
sta step ; *** WAS *** stz step
|
||||
asl phase
|
||||
copy_cur:
|
||||
lda curtrk
|
||||
sta tmptrk
|
||||
lda curtrk ; load current track
|
||||
sta tmptrk ; store as temtrk
|
||||
sec ; calc current-desired
|
||||
sbc phase ;
|
||||
beq seekret ; if they match, we are done!
|
||||
|
||||
bcs seek_neg ; if negative, skip ahead
|
||||
eor #$ff ; ones-complement the distance
|
||||
inc curtrk ; increment current?
|
||||
bcc L25 ; skip ahead
|
||||
seek_neg:
|
||||
sec
|
||||
sbc phase
|
||||
beq seekret
|
||||
bcs L24
|
||||
eor #$ff
|
||||
inc curtrk
|
||||
bcc L25
|
||||
L24:
|
||||
sec
|
||||
sbc #1 ; *** WAS *** dec
|
||||
sbc #1 ; *** WAS *** dec
|
||||
dec curtrk
|
||||
L25:
|
||||
cmp step
|
||||
@ -449,11 +485,32 @@ L27:
|
||||
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
|
||||
sectbl: .byte $00,$0d,$0b,$09,$07,$05,$03,$01,$0e,$0c,$0a,$08,$06,$04,$02,$0f
|
||||
|
||||
.align $100
|
||||
|
||||
codeend = *
|
||||
|
||||
nibtbl = *
|
||||
; From $BA96 of DOS33
|
||||
nibtbl = *
|
||||
; .byte $00,$01,$98,$99,$02,$03,$9C,$04 ; $BA96 ; 00
|
||||
; .byte $05,$06,$A0,$A1,$A2,$A4,$A4,$A5 ; $BA9E ; 08
|
||||
; .byte $07,$08,$A8,$A9,$AA,$09,$0A,$0B ; $BAA6 ; 10
|
||||
; .byte $0C,$0D,$B0,$B1,$0E,$0F,$10,$11 ; $BAAE ; 18
|
||||
; .byte $12,$13,$B8,$14,$15,$16,$17,$18 ; $BAB6 ; 20
|
||||
; .byte $19,$1A,$C0,$C1,$C2,$C3,$C4,$C5 ; $BABE ; 28
|
||||
; .byte $C6,$C7,$C8,$C9,$CA,$1B,$CC,$1C ; $BAC6 ; 30
|
||||
; .byte $1D,$1E,$D0,$D1,$D2,$1E,$D4,$D5 ; $BACE ; 38
|
||||
; .byte $20,$21,$D8,$22,$23,$24,$25,$26 ; $BAD6 ; 40
|
||||
; .byte $27,$28,$E0,$E1,$E2,$E3,$E4,$29 ; $BADE ; 48
|
||||
; .byte $2A,$2B,$E8,$2C,$2D,$2E,$2F,$30 ; $BAE6 ; 50
|
||||
; .byte $31,$32,$F0,$F1,$33,$34,$35,$36 ; $BAEE ; 58
|
||||
; .byte $37,$38,$F8,$39,$3A,$3B,$3C,$3D ; $BAF6 ; 60
|
||||
; .byte $3E,$3F,$13,$00,$01,$02,$01,$00 ; $BAFE ; 68
|
||||
; .byte $00,$00,$00,$00,$00,$00,$00,$00
|
||||
; .byte $00,$00,$00,$00,$00,$00,$00,$00
|
||||
|
||||
|
||||
bit2tbl = nibtbl+128
|
||||
filbuf = bit2tbl+86
|
||||
dataend = filbuf+4
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user