Thread: Assembler Help

Can anyone help me on this problem? I am trying to divide a negative and a posive number in asembler using the IDIV command. Say i divide -9/3 the result should be -3, but it outputs a strange number?
Any ideas? Much help appreciated.

You're probably not promoting the ax/eax sign into dx/edx. Using 32bits, it'd should look something like -

Code:

	int i=3;
	int j=-9;

	_asm
	{		
		mov eax,j
		cdq
		idiv i
		mov j,eax
	}

Thanks, that works for 32bit, but it has got to be done in 8086 16bit; with the correct answer for any combination of positive or negative numbers. It is really annoying me this.

Then try -

Code:

_asm
	{		
		mov ax,-9
                cwd
		idiv i
		mov j,ax
	}

Cheers, soz to blother you again is the remainder still being stored in the ah register i'm using this code to get it out:

short r;

mov cl,ah
mov r, cx

Got!!! Remainder stored in dx. Thanks for your help, how do you learn this???
V.greatful!!!