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From: herrickd@iccgcc.decnet.ab.com
Newsgroups: comp.arch
Subject: Re: new instructions
Message-ID: <4712.2843b438@iccgcc.decnet.ab.com>
Date: 29 May 91 19:01:28 GMT
References: <9105200213.AA05095@ucbvax.Berkeley.EDU> <1991May21.191034.25980@murdoch.acc.Virginia.EDU>
Lines: 23

Aren't you afraid you will spoil the argument by bringing some
facts into it?

In article <1991May21.191034.25980@murdoch.acc.Virginia.EDU>, clc5q@hemlock.cs.Virginia.EDU (Clark L. Coleman) writes:
[most of his wonderful data omitted - see the original article]
> 
> Given the C source code statement:
> 
> 	z = x % y;   /* z gets the remainder of x divided by y */
> 
> 
> 	movl	r6,r1		/* Transfer quotient to r1 */
> 	clrl	r0		/* Zero out upper word to form 64-bit r0/r1
> 				   register pair quotient */
> 	ediv	r7,r0,r2,r11	/* Divide r0-r1 pair by r7; throw away quotient
> 				   into r2 and keep remainder in r11 */
> 
This looks to me like it does only unsigned div/rem.  Is that a feature
of the ediv instruction or do we need a way to sign extend r1 into r0
for the signed division case?

dan herrick
herrickd@iccgcc.decnet.ab.com