4cade/src/4cade.init.cffa.a

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2020-08-12 15:35:21 +00:00
;license:MIT
;(c) 2020 by qkumba
;
; CFFA-specific work-around for an issue on the GS
;
HackThaCFFA
ldx #0
beq @CFFAbase1
@loopCFFA
cmp @CFFA_ID-1,x
bne @nextslot
@CFFAbase1
lda $C7F6,x
inx
cpx #5
bne @loopCFFA
sbc #'0'
cmp #2 ; only 3.0x and 3.1x
bcc @foundCFFA
rts
@nextslot
dec @CFFAbase1+2
lda @CFFAbase1+2
cmp #$C0
bne HackThaCFFA
rts
@foundCFFA
lda @CFFAbase1+2
sta @CFFAbase2+2
!cpu 65816
clc
xce
ldx #0
- inx
lda $FE0002,x
cmp #$FE ; find anything we can use as bank==#$FE
bne -
stx @patchROM+1
rep #$30
!al
!rl
sei
ldx #$00A0
lda $CFFF
@CFFAbase2
lda $D100 ; SMC
- dex
beq @returnCFFA
lda $CC04,x
eor #$02AE
bne -
tay
- lda @patchCFFA_b,y
sta $CC00,x
inx
inx
iny
iny
cpy #(@patchCFFA_e-@patchCFFA_b)
bcc -
@returnCFFA
cli
sec
xce
rts
!as
!rs
@patchCFFA_b
stz $C806
stz $C807 ; no error
@patchROM
lda #$D1 ; SMC
sta $C808
stz $C809
lda #$FE
sta $C80A ; handle at FE/00xx
stz $C80B
rts
@patchCFFA_e
@CFFA_ID !text "CF3K"
!cpu 6502