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INCLUDE "constants.asm"
SECTION "engine/bcd.asm", ROMX
AddBCD:
and a
ld b, c
.add
ld a, [de]
adc [hl]
daa
ld [de], a
dec de
dec hl
dec c
jr nz, .add
jr nc, .done
ld a, $99
inc de
.fill
ld [de], a
inc de
dec b
jr nz, .fill
.done
ret
SubBCD:
and a
ld b, c
.sub
ld a, [de]
sbc [hl]
daa
ld [de], a
dec de
dec hl
dec c
jr nz, .sub
jr nc, .done
ld a, 0
inc de
.fill
ld [de], a
inc de
dec b
jr nz, .fill
scf
.done
ret
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