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143 lines
3.2 KiB
NASM
Executable file
143 lines
3.2 KiB
NASM
Executable file
_Multiply: ; 37d41 (d:7d41)
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ld a, $8
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ld b, a
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xor a
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ld [H_PRODUCT], a
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ld [H_MULTIPLYBUFFER], a
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ld [H_MULTIPLYBUFFER+1], a
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ld [H_MULTIPLYBUFFER+2], a
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ld [H_MULTIPLYBUFFER+3], a
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.loop
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ld a, [H_MULTIPLIER]
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srl a
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ld [H_MULTIPLIER], a ; (aliases: H_DIVISOR, H_MULTIPLIER, H_POWEROFTEN)
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jr nc, .smallMultiplier
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ld a, [H_MULTIPLYBUFFER+3]
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ld c, a
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ld a, [H_MULTIPLICAND+2]
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add c
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ld [H_MULTIPLYBUFFER+3], a
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ld a, [H_MULTIPLYBUFFER+2]
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ld c, a
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ld a, [H_MULTIPLICAND+1]
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adc c
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ld [H_MULTIPLYBUFFER+2], a
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ld a, [H_MULTIPLYBUFFER+1]
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ld c, a
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ld a, [H_MULTIPLICAND] ; (aliases: H_MULTIPLICAND)
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adc c
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ld [H_MULTIPLYBUFFER+1], a
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ld a, [H_MULTIPLYBUFFER]
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ld c, a
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ld a, [H_PRODUCT] ; (aliases: H_PRODUCT, H_PASTLEADINGZEROES, H_QUOTIENT)
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adc c
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ld [H_MULTIPLYBUFFER], a
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.smallMultiplier
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dec b
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jr z, .done
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ld a, [H_MULTIPLICAND+2]
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sla a
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ld [H_MULTIPLICAND+2], a
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ld a, [H_MULTIPLICAND+1]
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rl a
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ld [H_MULTIPLICAND+1], a
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ld a, [H_MULTIPLICAND]
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rl a
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ld [H_MULTIPLICAND], a
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ld a, [H_PRODUCT]
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rl a
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ld [H_PRODUCT], a
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jr .loop
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.done
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ld a, [H_MULTIPLYBUFFER+3]
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ld [H_PRODUCT+3], a
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ld a, [H_MULTIPLYBUFFER+2]
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ld [H_PRODUCT+2], a
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ld a, [H_MULTIPLYBUFFER+1]
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ld [H_PRODUCT+1], a
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ld a, [H_MULTIPLYBUFFER]
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ld [H_PRODUCT], a
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ret
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_Divide: ; 37da5 (d:7da5)
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xor a
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ld [H_DIVIDEBUFFER], a
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ld [H_DIVIDEBUFFER+1], a
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ld [H_DIVIDEBUFFER+2], a
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ld [H_DIVIDEBUFFER+3], a
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ld [H_DIVIDEBUFFER+4], a
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ld a, $9
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ld e, a
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.asm_37db3
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ld a, [H_DIVIDEBUFFER]
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ld c, a
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ld a, [H_DIVIDEND+1] ; (aliases: H_MULTIPLICAND)
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sub c
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ld d, a
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ld a, [H_DIVISOR] ; (aliases: H_DIVISOR, H_MULTIPLIER, H_POWEROFTEN)
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ld c, a
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ld a, [H_DIVIDEND] ; (aliases: H_PRODUCT, H_PASTLEADINGZEROES, H_QUOTIENT)
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sbc c
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jr c, .asm_37dce
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ld [H_DIVIDEND], a ; (aliases: H_PRODUCT, H_PASTLEADINGZEROES, H_QUOTIENT)
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ld a, d
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ld [H_DIVIDEND+1], a ; (aliases: H_MULTIPLICAND)
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ld a, [H_DIVIDEBUFFER+4]
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inc a
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ld [H_DIVIDEBUFFER+4], a
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jr .asm_37db3
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.asm_37dce
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ld a, b
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cp $1
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jr z, .asm_37e18
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ld a, [H_DIVIDEBUFFER+4]
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sla a
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ld [H_DIVIDEBUFFER+4], a
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ld a, [H_DIVIDEBUFFER+3]
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rl a
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ld [H_DIVIDEBUFFER+3], a
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ld a, [H_DIVIDEBUFFER+2]
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rl a
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ld [H_DIVIDEBUFFER+2], a
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ld a, [H_DIVIDEBUFFER+1]
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rl a
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ld [H_DIVIDEBUFFER+1], a
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dec e
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jr nz, .asm_37e04
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ld a, $8
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ld e, a
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ld a, [H_DIVIDEBUFFER]
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ld [H_DIVISOR], a ; (aliases: H_DIVISOR, H_MULTIPLIER, H_POWEROFTEN)
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xor a
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ld [H_DIVIDEBUFFER], a
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ld a, [H_DIVIDEND+1] ; (aliases: H_MULTIPLICAND)
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ld [H_DIVIDEND], a ; (aliases: H_PRODUCT, H_PASTLEADINGZEROES, H_QUOTIENT)
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ld a, [H_DIVIDEND+2]
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ld [H_DIVIDEND+1], a ; (aliases: H_MULTIPLICAND)
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ld a, [H_DIVIDEND+3]
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ld [H_DIVIDEND+2], a
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.asm_37e04
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ld a, e
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cp $1
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jr nz, .asm_37e0a
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dec b
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.asm_37e0a
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ld a, [H_DIVISOR] ; (aliases: H_DIVISOR, H_MULTIPLIER, H_POWEROFTEN)
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srl a
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ld [H_DIVISOR], a ; (aliases: H_DIVISOR, H_MULTIPLIER, H_POWEROFTEN)
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ld a, [H_DIVIDEBUFFER]
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rr a
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ld [H_DIVIDEBUFFER], a
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jr .asm_37db3
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.asm_37e18
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ld a, [H_DIVIDEND+1] ; (aliases: H_MULTIPLICAND)
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ld [H_REMAINDER], a ; (aliases: H_DIVISOR, H_MULTIPLIER, H_POWEROFTEN)
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ld a, [H_DIVIDEBUFFER+4]
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ld [H_QUOTIENT+3], a
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ld a, [H_DIVIDEBUFFER+3]
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ld [H_QUOTIENT+2], a
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ld a, [H_DIVIDEBUFFER+2]
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ld [H_QUOTIENT+1], a ; (aliases: H_MULTIPLICAND)
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ld a, [H_DIVIDEBUFFER+1]
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ld [H_DIVIDEND], a ; (aliases: H_PRODUCT, H_PASTLEADINGZEROES, H_QUOTIENT)
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ret
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