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I'm stuck

Awhile back I asked if there was a way to divide dx:ax by bx and get a double word anwer. (like FFFFFFFFh / Ah = 19999999h) and I got this peice of code.....

Code:
;*dx:ax/bx; dx:ax = answer, cx = remainder*

push ax            ;save ax (lower word)

mov ax,dx        ;higher word into ax so it can be divided

xor dx,dx        ;dx = 0

div bx            ;dx:ax/bx; ax = answer dx = remainder

mov cx,ax        ;save higher word

pop ax            ;get ax, the lower word

div bx            ;dx:ax/bx again

xchg dx,cx        ;extange;dx = higher word cx = remainder

I was wondering if anyone knew how to do the same thing with the "idiv" (divide with sign) function. Thanks.

If that code above is correct (too lazy to check it now), just replace div with idiv.

Sorry I took so long....
I got this piece of code to work most of the time but when I tried to divide 6 0000h by Ah or 6 0000h by FFF6 (-Ah) I get a divide overflow error.

Code:
;Register        Function

;dx:ax    dividend (number to be divided)

;bx        divisor (number dividend is divided by)

;

;dx:ax/bx     dx:ax = answer, cx = remainder

push ax        ;save ax (lower word)

mov ax,dx    ;higher word into ax so it can be divided

cwd              ;convert dx:ax to word

idiv bx          ;dx:ax/bx; ax = answer dx = remainder

mov cx,ax        ;save higher word

pop ax         ;get ax, the lower word

idiv bx          ;dx:ax/bx again

xchg dx,cx    ;extange;dx = higher word cx = remainder

Why not try to do a:

Code:
Cwde

Cdq

Movsx ebx, bx

idiv ebx

instead of a

Code:
cwd

idiv bx

Dunno if you can use extended regs though. :*)

I'm using DEBUG.exe I can't use double words... Sad

http://www.aogosoft.com/download/debug32.rar

rCX

DrV

rCX

relsoft

rCX

Plasma