mirror of
https://github.com/a2-4am/passport.git
synced 2024-12-22 19:30:50 +00:00
improve detection of unformatted tracks and nibble count tracks (fixes Thunderbombs, Hi-Res Football, and many others)
This commit is contained in:
4am
parent
1b9a1c847e
commit
9d9146382b
191
src/analyze.a
191
src/analyze.a
@ -6,55 +6,37 @@
|
||||
!zone {
|
||||
SkipTrack
|
||||
;
|
||||
; 1) $EEEF protection track (EEEFBBBAFAAE nibble sequence)
|
||||
; [must come first because track would otherwise pass the IsUnformatted test below]
|
||||
; [speed optimization: only check on track $22]
|
||||
; Electronic Arts protection track?
|
||||
;
|
||||
.checkeeef
|
||||
lda gTrack
|
||||
cmp #$22
|
||||
bne .checkunformat
|
||||
jsr IsEEEF
|
||||
bcs .checkunformat
|
||||
lda #s_eeef
|
||||
bcc .skiptrack ; always taken
|
||||
jsr IsEATrack6
|
||||
lda #s_eatrk6
|
||||
bcc .print
|
||||
;
|
||||
; 2) unformatted track
|
||||
; Unformatted track?
|
||||
;
|
||||
.checkunformat
|
||||
jsr IsUnformatted
|
||||
bcs .checkf7f6
|
||||
+ lda #s_unformat
|
||||
bcc .skiptrack ; always taken
|
||||
bcs +
|
||||
;
|
||||
; 3) $F7F6 protection track (F7F6EFEAAB nibble sequence)
|
||||
; $F7F6EFEAAB protection track?
|
||||
; (initially presents as unformatted, needs separate test because it
|
||||
; triggers special handling)
|
||||
;
|
||||
.checkf7f6
|
||||
jsr IsF7F6
|
||||
bcs .checksync
|
||||
lda #s_unformat
|
||||
bcs .print
|
||||
lda #s_f7
|
||||
bit gMode
|
||||
bpl .checksync
|
||||
bvc .checksync
|
||||
bpl .print
|
||||
bvc .print
|
||||
; if we're in 'crack' mode, restart the scan to find the protection code
|
||||
jmp SetupF7F6SecondRound
|
||||
;
|
||||
; 4) nibble count track (mostly $FF sync bytes)
|
||||
; Nibble count track?
|
||||
;
|
||||
.checksync
|
||||
jsr IsSyncBytes
|
||||
bcs .checktrack6
|
||||
+ jsr JustTheSameDamnThingOverAndOver
|
||||
bcs .donotskip
|
||||
lda #s_sync
|
||||
bcc .skiptrack ; always taken
|
||||
|
||||
;
|
||||
; 5) track simply does not exist (Electronic Arts in particular)
|
||||
;
|
||||
.checktrack6
|
||||
jsr IsEATrack6
|
||||
bcs .fail
|
||||
lda #s_eatrk6
|
||||
; note: execution falls through here
|
||||
.skiptrack
|
||||
.print
|
||||
jsr PrintByID
|
||||
;
|
||||
; Skipping T22 on a ProDOS disk might indicate the presence of a
|
||||
@ -73,7 +55,7 @@ SkipTrack
|
||||
sta gPossibleGamco
|
||||
+ clc
|
||||
!byte $24 ; hides next SEC
|
||||
.fail
|
||||
.donotskip
|
||||
sec
|
||||
rts
|
||||
}
|
||||
@ -93,7 +75,7 @@ IsF7F6
|
||||
lda $C0E9
|
||||
lda #$00
|
||||
jsr WAIT
|
||||
lda #$20
|
||||
lda #$19
|
||||
sta nibcount
|
||||
ldy #$00
|
||||
- lda $C0EC
|
||||
@ -162,108 +144,87 @@ SetupF7F6SecondRound
|
||||
jmp RestartScan
|
||||
|
||||
;-------------------------------
|
||||
; IsEEEF
|
||||
; check for a specific nibble sequence
|
||||
; ("EE EF BB BA FA AE") that is used by a
|
||||
; whole-track protection scheme
|
||||
; JustTheSameDamnThingOverAndOver
|
||||
; check if track has a large sequence of repeated bytes
|
||||
;
|
||||
; in slot 6, drive 1 is on track to test
|
||||
; out C clear if sequence was found
|
||||
; C set if sequence was not found
|
||||
; out C clear if found
|
||||
; C set otherwise
|
||||
;-------------------------------
|
||||
!zone {
|
||||
IsEEEF
|
||||
JustTheSameDamnThingOverAndOver
|
||||
lda $C0E9
|
||||
lda #$00
|
||||
jsr WAIT
|
||||
lda #$20
|
||||
sta nibcount
|
||||
ldy #$00
|
||||
- lda $C0EC
|
||||
bpl -
|
||||
cmp #$EE
|
||||
beq +
|
||||
.restart iny
|
||||
bne -
|
||||
dec nibcount
|
||||
bne -
|
||||
beq .fail
|
||||
+
|
||||
- lda $C0EC
|
||||
bpl -
|
||||
cmp #$EF
|
||||
bne .restart
|
||||
- lda $C0EC
|
||||
bpl -
|
||||
cmp #$BB
|
||||
bne .restart
|
||||
- lda $C0EC
|
||||
bpl -
|
||||
cmp #$BA
|
||||
bne .restart
|
||||
- lda $C0EC
|
||||
bpl -
|
||||
cmp #$FA
|
||||
bne .restart
|
||||
- lda $C0EC
|
||||
bpl -
|
||||
cmp #$AE
|
||||
bne .restart
|
||||
lda #$19
|
||||
sta unform+1
|
||||
ldx #$00
|
||||
;
|
||||
; Timing-sensitive code! Cycle counts in margin for worst case path
|
||||
;
|
||||
.reset ldy #$00 ; 2
|
||||
sta .cmp+1 ; 4
|
||||
.loop lda $C0EC
|
||||
bpl .loop ; 3 when not taken
|
||||
dex ; 2
|
||||
bne .cmp ; 3 when not taken
|
||||
dec unform+1 ; 5
|
||||
beq .notfound ; 3 when not taken
|
||||
.cmp cmp #$d1 ; 2
|
||||
bne .reset ; 3 when not taken
|
||||
iny ; 2
|
||||
bne .loop ; 2 when taken
|
||||
clc
|
||||
!byte $24 ; hides SEC
|
||||
.fail sec
|
||||
!byte $24
|
||||
.notfound
|
||||
sec
|
||||
lda $C0E8
|
||||
rts
|
||||
}
|
||||
|
||||
;-------------------------------
|
||||
; IsSyncBytes
|
||||
; check if track is mostly $FF bytes
|
||||
;
|
||||
; in slot 6, drive 1 is on track to test
|
||||
; out C clear if track is mostly just $FF bytes
|
||||
; C set otherwise
|
||||
;-------------------------------
|
||||
IsSyncBytes
|
||||
lda #$FD
|
||||
sta gNIBTableFF
|
||||
jsr IsUnformatted
|
||||
lda #$3F
|
||||
sta gNIBTableFF
|
||||
rts
|
||||
|
||||
;-------------------------------
|
||||
; IsUnformatted
|
||||
; check if track is unformatted
|
||||
; check if track is unformatted by counting
|
||||
; the number of valid nibbles in a row
|
||||
;
|
||||
; in slot 6, drive 1 is on track to test
|
||||
; out C clear if track is unformatted
|
||||
; C set if track is formatted
|
||||
;-------------------------------
|
||||
!zone {
|
||||
IsUnformatted
|
||||
lda #$FD
|
||||
sta gNIBTableFF
|
||||
|
||||
lda $C0E9
|
||||
jsr WAIT
|
||||
lda #$00
|
||||
sta unform
|
||||
lda #$19
|
||||
sta unform+1
|
||||
jsr WAIT
|
||||
lda #$20
|
||||
sta nibcount
|
||||
ldy #$00
|
||||
nibloop ldx $C0EC
|
||||
bpl nibloop
|
||||
lda gNIBTable,x
|
||||
bpl +
|
||||
inc unform
|
||||
bne +
|
||||
inc unform+1
|
||||
+ iny
|
||||
bne nibloop
|
||||
dec nibcount
|
||||
bne nibloop
|
||||
;
|
||||
; Timing-sensitive code! Cycle counts in margin for worst case path
|
||||
;
|
||||
.reset ldy #$00
|
||||
.loop ldx $C0EC
|
||||
bpl .loop ; 3 when not taken
|
||||
dec unform ; 5
|
||||
bne + ; 3 when not taken
|
||||
dec unform+1 ; 5
|
||||
beq .unformatted;3 when not taken
|
||||
+ lda gNIBTable,x; 4
|
||||
bmi .reset ; 3 when not taken
|
||||
iny ; 2
|
||||
bne .loop ; 2 when taken
|
||||
sec
|
||||
!byte $24
|
||||
.unformatted
|
||||
clc
|
||||
lda $C0E8
|
||||
lda #$18
|
||||
cmp unform+1
|
||||
|
||||
lda #$3F
|
||||
sta gNIBTableFF
|
||||
rts
|
||||
}
|
||||
|
||||
;-------------------------------
|
||||
; xHeredityDog
|
||||
|
||||
@ -137,7 +137,7 @@ StringTable
|
||||
; can be set directly before calling PrintByID.
|
||||
;
|
||||
.header
|
||||
!text "Passport by 4am 2017-12-26",$00
|
||||
!text "Passport by 4am 2017-12-27",$00
|
||||
.mainmenu
|
||||
!text "________________________________________",$8D,$8D,$8D,$8D,$8D,$8D,$8D
|
||||
!text " "
|
||||
@ -370,7 +370,7 @@ StringTable
|
||||
.eatrk6
|
||||
!text "T06 Found EA protection track",$8D,$00
|
||||
.eeef
|
||||
!text "T%t Found $EEEFBBBA protection track",$8D,$00
|
||||
!byte $00
|
||||
.poke
|
||||
!text "T%t,S%0 BASIC program POKEs protection",$8D
|
||||
!text "check into memory and CALLs it.",$8D,$00
|
||||
|
||||
Loading…
Reference in New Issue
Block a user