Programming:Integer Division: Difference between revisions
Appearance
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
== 16bit division == | |||
'''Input:''' BC=Value1, DE=Value2 | |||
'''Output:''' HL=Value1/Value2, DE=Value1 MOD Value2 | |||
'''Destroyed:''' AF,BC | |||
<pre> | |||
clcd16 ld a,e | |||
or d | |||
ld hl,0 | |||
ret z | |||
ld a,b | |||
ld b,16 | |||
clcd161 rl c | |||
rla | |||
rl l | |||
rl h | |||
sbc hl,de | |||
jr nc,clcd162 | |||
add hl,de | |||
clcd162 ccf | |||
djnz clcd161 | |||
ex de,hl | |||
rl c | |||
rla | |||
ld h,a | |||
ld l,c | |||
ret | |||
</pre> | |||
== 24bit division == | |||
'''Input:''' A,BC=Value1, DE=Value2 | |||
'''Output:''' HL=Value1/Value2, DE=Value1 MOD Value2 | |||
'''Destroyed:''' AF,BC,IX,IYL | |||
<pre> | |||
clcdiv db #dd:ld l,e | |||
db #dd:ld h,d ;IX=Value2 | |||
ld e,a ;E,BC=Value1(Counter) | |||
ld hl,0 | |||
db #dd:ld a,l | |||
db #dd:or h | |||
ret z | |||
ld d,l ;D,HL=CalcVar | |||
db #fd:ld l,24 ;IYL=Counter | |||
clcdiv1 rl c | |||
rl b | |||
rl e | |||
rl l | |||
rl h | |||
rl d | |||
ld a,l | |||
db #dd:sub l | |||
ld l,a | |||
ld a,h | |||
db #dd:sbc h | |||
ld h,a | |||
ld a,d | |||
sbc 0 | |||
ld d,a ;D,HL=D,HL-IX | |||
jr nc,clcdiv2 | |||
ld a,l | |||
db #dd:add l | |||
ld l,a | |||
ld a,h | |||
db #dd:adc h | |||
ld h,a | |||
ld a,d | |||
adc 0 | |||
ld d,a | |||
scf | |||
clcdiv2 ccf | |||
db #fd:dec l | |||
jr nz,clcdiv1 | |||
ex de,hl ;DE=Value1 MOD Value2 | |||
rl c | |||
rl b | |||
ld l,c | |||
ld h,b ;HL=Value1 DIV Value2 | |||
ret | |||
</pre> | |||
== 32bit division == | == 32bit division == | ||
Revision as of 01:40, 5 August 2006
16bit division
Input: BC=Value1, DE=Value2
Output: HL=Value1/Value2, DE=Value1 MOD Value2
Destroyed: AF,BC
clcd16 ld a,e
or d
ld hl,0
ret z
ld a,b
ld b,16
clcd161 rl c
rla
rl l
rl h
sbc hl,de
jr nc,clcd162
add hl,de
clcd162 ccf
djnz clcd161
ex de,hl
rl c
rla
ld h,a
ld l,c
ret
24bit division
Input: A,BC=Value1, DE=Value2
Output: HL=Value1/Value2, DE=Value1 MOD Value2
Destroyed: AF,BC,IX,IYL
clcdiv db #dd:ld l,e
db #dd:ld h,d ;IX=Value2
ld e,a ;E,BC=Value1(Counter)
ld hl,0
db #dd:ld a,l
db #dd:or h
ret z
ld d,l ;D,HL=CalcVar
db #fd:ld l,24 ;IYL=Counter
clcdiv1 rl c
rl b
rl e
rl l
rl h
rl d
ld a,l
db #dd:sub l
ld l,a
ld a,h
db #dd:sbc h
ld h,a
ld a,d
sbc 0
ld d,a ;D,HL=D,HL-IX
jr nc,clcdiv2
ld a,l
db #dd:add l
ld l,a
ld a,h
db #dd:adc h
ld h,a
ld a,d
adc 0
ld d,a
scf
clcdiv2 ccf
db #fd:dec l
jr nz,clcdiv1
ex de,hl ;DE=Value1 MOD Value2
rl c
rl b
ld l,c
ld h,b ;HL=Value1 DIV Value2
ret
32bit division
Input: IY,BC=Value1, IX=Value2
Output: IY,BC=Value1/Value2, HL=Value1 MOD Value2
Destroyed: AF,DE,IY
clcd32c db 0
clcd32 ld hl,0
db #dd:ld a,l
db #dd:or h
ret z ;IY,BC=Value1(Counter)
ld de,0 ;DE,HL=CalcVar
ld a,32 ;Set Counter to 32
clcd321 ld (clcd32c),a
rl c
rl b
db #fd:ld a,l:rla:db #fd:ld l,a
db #fd:ld a,h:rla:db #fd:ld h,a
rl l
rl h
rl e
rl d
ld a,l
db #dd:sub l
ld l,a
ld a,h
db #dd:sbc h
ld h,a
ld a,e
sbc 0
ld e,a
ld a,d
sbc 0
ld d,a
jr nc,clcd322
ld a,l
db #dd:add l
ld l,a
ld a,h
db #dd:adc h
ld h,a
ld a,e
adc 0
ld e,a
ld a,d
adc 0
ld d,a
scf
clcd322 ccf
ld a,(clcd32c)
dec a
jr nz,clcd321 ;HL=Value1 MOD Value2
rl c
rl b
db #fd:ld a,l:rla:db #fd:ld l,a
db #fd:ld a,h:rla:db #fd:ld h,a
ret ;IY,BC=Value1 DIV Value2