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_Multiply::
ld a, $8
ld b, a
xor a
ldh [hProduct], a
ldh [hMultiplyBuffer], a
ldh [hMultiplyBuffer+1], a
ldh [hMultiplyBuffer+2], a
ldh [hMultiplyBuffer+3], a
.loop
ldh a, [hMultiplier]
srl a
ldh [hMultiplier], a ; (aliases: hDivisor, hMultiplier, hPowerOf10)
jr nc, .smallMultiplier
ldh a, [hMultiplyBuffer+3]
ld c, a
ldh a, [hMultiplicand+2]
add c
ldh [hMultiplyBuffer+3], a
ldh a, [hMultiplyBuffer+2]
ld c, a
ldh a, [hMultiplicand+1]
adc c
ldh [hMultiplyBuffer+2], a
ldh a, [hMultiplyBuffer+1]
ld c, a
ldh a, [hMultiplicand] ; (aliases: hMultiplicand)
adc c
ldh [hMultiplyBuffer+1], a
ldh a, [hMultiplyBuffer]
ld c, a
ldh a, [hProduct] ; (aliases: hProduct, hPastLeadingZeros, hQuotient)
adc c
ldh [hMultiplyBuffer], a
.smallMultiplier
dec b
jr z, .done
ldh a, [hMultiplicand+2]
sla a
ldh [hMultiplicand+2], a
ldh a, [hMultiplicand+1]
rl a
ldh [hMultiplicand+1], a
ldh a, [hMultiplicand]
rl a
ldh [hMultiplicand], a
ldh a, [hProduct]
rl a
ldh [hProduct], a
jr .loop
.done
ldh a, [hMultiplyBuffer+3]
ldh [hProduct+3], a
ldh a, [hMultiplyBuffer+2]
ldh [hProduct+2], a
ldh a, [hMultiplyBuffer+1]
ldh [hProduct+1], a
ldh a, [hMultiplyBuffer]
ldh [hProduct], a
ret
_Divide::
xor a
ldh [hDivideBuffer], a
ldh [hDivideBuffer+1], a
ldh [hDivideBuffer+2], a
ldh [hDivideBuffer+3], a
ldh [hDivideBuffer+4], a
ld a, $9
ld e, a
.loop
ldh a, [hDivideBuffer]
ld c, a
ldh a, [hDividend+1] ; (aliases: hMultiplicand)
sub c
ld d, a
ldh a, [hDivisor] ; (aliases: hDivisor, hMultiplier, hPowerOf10)
ld c, a
ldh a, [hDividend] ; (aliases: hProduct, hPastLeadingZeros, hQuotient)
sbc c
jr c, .next
ldh [hDividend], a ; (aliases: hProduct, hPastLeadingZeros, hQuotient)
ld a, d
ldh [hDividend+1], a ; (aliases: hMultiplicand)
ldh a, [hDivideBuffer+4]
inc a
ldh [hDivideBuffer+4], a
jr .loop
.next
ld a, b
cp $1
jr z, .done
ldh a, [hDivideBuffer+4]
sla a
ldh [hDivideBuffer+4], a
ldh a, [hDivideBuffer+3]
rl a
ldh [hDivideBuffer+3], a
ldh a, [hDivideBuffer+2]
rl a
ldh [hDivideBuffer+2], a
ldh a, [hDivideBuffer+1]
rl a
ldh [hDivideBuffer+1], a
dec e
jr nz, .next2
ld a, $8
ld e, a
ldh a, [hDivideBuffer]
ldh [hDivisor], a ; (aliases: hDivisor, hMultiplier, hPowerOf10)
xor a
ldh [hDivideBuffer], a
ldh a, [hDividend+1] ; (aliases: hMultiplicand)
ldh [hDividend], a ; (aliases: hProduct, hPastLeadingZeros, hQuotient)
ldh a, [hDividend+2]
ldh [hDividend+1], a ; (aliases: hMultiplicand)
ldh a, [hDividend+3]
ldh [hDividend+2], a
.next2
ld a, e
cp $1
jr nz, .okay
dec b
.okay
ldh a, [hDivisor] ; (aliases: hDivisor, hMultiplier, hPowerOf10)
srl a
ldh [hDivisor], a ; (aliases: hDivisor, hMultiplier, hPowerOf10)
ldh a, [hDivideBuffer]
rr a
ldh [hDivideBuffer], a
jr .loop
.done
ldh a, [hDividend+1] ; (aliases: hMultiplicand)
ldh [hRemainder], a ; (aliases: hDivisor, hMultiplier, hPowerOf10)
ldh a, [hDivideBuffer+4]
ldh [hQuotient+3], a
ldh a, [hDivideBuffer+3]
ldh [hQuotient+2], a
ldh a, [hDivideBuffer+2]
ldh [hQuotient+1], a ; (aliases: hMultiplicand)
ldh a, [hDivideBuffer+1]
ldh [hDividend], a ; (aliases: hProduct, hPastLeadingZeros, hQuotient)
ret
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