mirror of https://github.com/a2-4am/anti-m.git
67 lines
1.3 KiB
Plaintext
67 lines
1.3 KiB
Plaintext
; SpiraDisc tracer
|
|
; written by qkumba
|
|
;
|
|
; tested on
|
|
; - Frogger
|
|
; - Jawbreaker ][
|
|
; - Lunar Leepers
|
|
; - Pest Patrol
|
|
;
|
|
IDSpiraDisc
|
|
lda #8
|
|
ldx #1
|
|
ldy #12
|
|
jsr CompareMemory
|
|
!byte $86,$0A ;STA $0A
|
|
!byte $8E,WILDCARD,WILDCARD ;STA $xxxx
|
|
!byte $8E,WILDCARD,WILDCARD ;STA $xxxx
|
|
!byte $90,$78 ;BCC *+$7A
|
|
!byte $D0,$01 ;BNE *+$03
|
|
bcs @exit
|
|
|
|
; patch code to regain control after it loads sectors into $B500+
|
|
lda #<@callback1
|
|
sta $0870
|
|
lda #>@callback1
|
|
sta $0871
|
|
|
|
@exit
|
|
rts
|
|
|
|
@callback1
|
|
lda $85FF
|
|
beq @skip2
|
|
lda $B5F9
|
|
cmp #$8A
|
|
bne +
|
|
inc $B5F9
|
|
+ lda $B608
|
|
cmp #$8A
|
|
bne +
|
|
inc $B608
|
|
+ lda $B618
|
|
cmp #$8A
|
|
bne +
|
|
inc $B618
|
|
+
|
|
|
|
@skip2
|
|
|
|
; disable ROM checksum-failure branching
|
|
lda $B845
|
|
cmp #$5C
|
|
bne +
|
|
lda #0
|
|
sta $B845
|
|
; and boot PROM checksum-failure branching
|
|
sta $B606
|
|
lda #$24
|
|
sta $B60A
|
|
; and slot checksum-failure branching
|
|
lda #$FD
|
|
sta $BF41
|
|
; and slot scanning entirely
|
|
lda #$D0
|
|
sta $B899
|
|
+ jmp $B800
|