Programming:Integer Division
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8bit division
Input: HL=Value1, C=Value2
Output: L=Value1/Value2, H=Value1 MOD Value2
Destroyed: AF,BC
LD B,8 Div_Next: ADD HL,HL LD A,H SUB C JR C,Div_NXTB LD H,A INC L Div_NXTB: DJNZ Div_Next RET
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 adc hl,hl 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
Fast 32bit division
Input: HL,DE=Value1, BC=Value2
Output: BCDE=Value1/Value2, HL=Value1 MOD Value2
Destroyed: AF
Not used: IX, IY
div macro local t1,t2 ADD HL, HL EX DE, HL ADD HL, HL EX DE, HL JP NC, t1 INC HL t1 LD A, L ADD A, C LD A, H ADC A, B JP NC, t2 ADD HL, BC INC DE t2 endm div32x16 proc ; BCDE = HLDE/BC, HL = HLDE%BC local t1, DIV32_, DIV320 DEC BC LD A, B CPL LD B, A LD A, C CPL LD C, A ADD A, L LD A, B ADC A, H JP NC, DIV32_ PUSH DE EX DE, HL LD HL, 0000 CALL DIV320 EX DE, HL EX (SP), HL EX DE, HL CALL DIV320 POP BC RET DIV32_ CALL DIV320 LD BC, 0000 RET DIV320 ; DE = HLDE/(-BC), HL = HLDE%(-BC) CALL t1 t1 rept 8 div endm RET endp