_Multiply: ld a, $8 ld b, a xor a ld [H_PRODUCT], a ld [H_MULTIPLYBUFFER], a ld [H_MULTIPLYBUFFER+1], a ld [H_MULTIPLYBUFFER+2], a ld [H_MULTIPLYBUFFER+3], a .multiplyLoop ld a, [H_MULTIPLIER] srl a ld [H_MULTIPLIER], a jr nc, .smallMultiplier ; less than $80 ; code to possibly multiply the multiplicand by 2 and divide the multiplier by 2? ld a, [H_MULTIPLYBUFFER+3] ld c, a ld a, [H_MULTIPLICAND+2] add c ld [H_MULTIPLYBUFFER+3], a ld a, [H_MULTIPLYBUFFER+2] ld c, a ld a, [H_MULTIPLICAND+1] adc c ld [H_MULTIPLYBUFFER+2], a ld a, [H_MULTIPLYBUFFER+1] ld c, a ld a, [H_MULTIPLICAND] adc c ld [H_MULTIPLYBUFFER+1], a ld a, [H_MULTIPLYBUFFER] ld c, a ld a, [H_PRODUCT] adc c ld [H_MULTIPLYBUFFER], a .smallMultiplier dec b jr z, .done ld a, [H_MULTIPLICAND+2] sla a ld [H_MULTIPLICAND+2], a ld a, [H_MULTIPLICAND+1] rl a ld [H_MULTIPLICAND+1], a ld a, [H_MULTIPLICAND] rl a ld [H_MULTIPLICAND], a ld a, [H_PRODUCT] rl a ld [H_PRODUCT], a jr .multiplyLoop .done ld a, [H_MULTIPLYBUFFER+3] ld [H_PRODUCT+3], a ld a, [H_MULTIPLYBUFFER+2] ld [H_PRODUCT+2], a ld a, [H_MULTIPLYBUFFER+1] ld [H_PRODUCT+1], a ld a, [H_MULTIPLYBUFFER] ld [H_PRODUCT], a ret _Divide: xor a ld [H_DIVIDEBUFFER], a ld [H_DIVIDEBUFFER+1], a ld [H_DIVIDEBUFFER+2], a ld [H_DIVIDEBUFFER+3], a ld [H_DIVIDEBUFFER+4], a ld a, $9 ld e, a .asm_f6680 ld a, [H_DIVIDEBUFFER] ld c, a ld a, [H_DIVIDEND+1] sub c ld d, a ld a, [H_DIVISOR] ld c, a ld a, [H_DIVIDEND] sbc c jr c, .asm_f669b ld [H_DIVIDEND], a ld a, d ld [H_DIVIDEND+1], a ld a, [H_DIVIDEBUFFER+4] inc a ld [H_DIVIDEBUFFER+4], a jr .asm_f6680 .asm_f669b ld a, b cp $1 jr z, .done ld a, [H_DIVIDEBUFFER+4] sla a ld [H_DIVIDEBUFFER+4], a ld a, [H_DIVIDEBUFFER+3] rl a ld [H_DIVIDEBUFFER+3], a ld a, [H_DIVIDEBUFFER+2] rl a ld [H_DIVIDEBUFFER+2], a ld a, [H_DIVIDEBUFFER+1] rl a ld [H_DIVIDEBUFFER+1], a dec e jr nz, .asm_f66d1 ld a, $8 ld e, a ld a, [H_DIVIDEBUFFER] ld [H_DIVISOR], a xor a ld [H_DIVIDEBUFFER], a ld a, [H_DIVIDEND+1] ld [H_DIVIDEND], a ld a, [H_DIVIDEND+2] ld [H_DIVIDEND+1], a ld a, [H_DIVIDEND+3] ld [H_DIVIDEND+2], a .asm_f66d1 ld a, e cp $1 jr nz, .asm_f66d7 dec b .asm_f66d7 ld a, [H_DIVISOR] srl a ld [H_DIVISOR], a ld a, [H_DIVIDEBUFFER] rr a ld [H_DIVIDEBUFFER], a jr .asm_f6680 .done ld a, [H_DIVIDEND+1] ld [H_REMAINDER], a ld a, [H_DIVIDEBUFFER+4] ld [H_QUOTIENT+3], a ld a, [H_DIVIDEBUFFER+3] ld [H_QUOTIENT+2], a ld a, [H_DIVIDEBUFFER+2] ld [H_QUOTIENT+1], a ld a, [H_DIVIDEBUFFER+1] ld [H_QUOTIENT], a ret