4cade/src/fx/fx.shr.lr.a

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;license:MIT
;(c) 2021 by 4am
!cpu 6502
!to "build/FX.INDEXED/SHR.LR",plain
*=$A000
!source "src/fx/fx.shr.common.a"
shrlo = $301 ; $C8 bytes
shrhi = $38 ; $C8 bytes
ldx #(end-start-1) ; copy loop to zero page
- lda start, x
sta $00, x
dex
bpl -
+BUILD_SHR_LOOKUP_TABLES shrlo, shrhi
;X=0
+COPY_SCB_AND_PALETTES
;WRITEAUXMEM active
ldy #0
jmp loop
start
!pseudopc 0 {
;Y=0
loop ldx #$C8
loop2 lda shrlo-1, x
sta <dst+1
lda shrhi-1, x
sta <dst+2
lda (<dst+1), y
dst sta $0000, y ; SMC
dex
bne loop2
lda $C000
bmi @exit
iny
cpy #$A0
bne loop
@exit
rts
}
end
; if zero page code gets too large, move shrhi to $201
!if end-start > $38 {
!error "code is too large: ends at ", end-start
}