2015-07-25 11:25:37 -07:00
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AddNTimes:: ; 0x30fe
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; Add bc * a to hl.
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and a
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ret z
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.loop
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add hl, bc
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dec a
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jr nz, .loop
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ret
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; 0x3105
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2014-02-01 17:26:39 -08:00
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SimpleMultiply:: ; 3105
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2013-09-08 22:21:36 -07:00
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; Return a * c.
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and a
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ret z
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push bc
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ld b, a
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|
xor a
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.loop
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add c
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|
dec b
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jr nz, .loop
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|
pop bc
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ret
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|
; 3110
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2014-02-01 17:26:39 -08:00
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SimpleDivide:: ; 3110
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2013-09-08 22:21:36 -07:00
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|
; Divide a by c. Return quotient b and remainder a.
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|
ld b, 0
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|
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|
.loop
|
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|
|
inc b
|
|
|
|
sub c
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|
|
|
jr nc, .loop
|
|
|
|
dec b
|
|
|
|
add c
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|
|
|
ret
|
|
|
|
; 3119
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|
2014-02-01 17:26:39 -08:00
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Multiply:: ; 3119
|
2013-09-08 22:21:36 -07:00
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|
; Multiply hMultiplicand (3 bytes) by hMultiplier. Result in hProduct.
|
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|
; All values are big endian.
|
|
|
|
push hl
|
|
|
|
push bc
|
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|
|
2017-12-24 09:47:30 -08:00
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|
callfar _Multiply
|
2013-09-08 22:21:36 -07:00
|
|
|
|
|
|
|
pop bc
|
|
|
|
pop hl
|
|
|
|
ret
|
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|
|
; 3124
|
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|
|
2014-02-01 17:26:39 -08:00
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Divide:: ; 3124
|
2013-09-08 22:21:36 -07:00
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|
; Divide hDividend length b (max 4 bytes) by hDivisor. Result in hQuotient.
|
|
|
|
; All values are big endian.
|
|
|
|
push hl
|
|
|
|
push de
|
|
|
|
push bc
|
2016-05-27 07:41:59 -07:00
|
|
|
homecall _Divide
|
2013-09-08 22:21:36 -07:00
|
|
|
pop bc
|
|
|
|
pop de
|
|
|
|
pop hl
|
|
|
|
ret
|
|
|
|
; 3136
|
|
|
|
|
|
|
|
|
2014-02-01 17:26:39 -08:00
|
|
|
SubtractSigned:: ; 3136
|
2013-09-08 22:21:36 -07:00
|
|
|
; Return a - b, sign in carry.
|
|
|
|
sub b
|
|
|
|
ret nc
|
|
|
|
cpl
|
|
|
|
add 1
|
|
|
|
scf
|
|
|
|
ret
|
|
|
|
; 313d
|