From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from oss.sgi.com (localhost [127.0.0.1]) by oss.sgi.com (8.12.5/8.12.5) with ESMTP id g6V0USRw012126 for ; Tue, 30 Jul 2002 17:30:28 -0700 Received: (from majordomo@localhost) by oss.sgi.com (8.12.5/8.12.3/Submit) id g6V0USBd012125 for linux-mips-outgoing; Tue, 30 Jul 2002 17:30:28 -0700 X-Authentication-Warning: oss.sgi.com: majordomo set sender to owner-linux-mips@oss.sgi.com using -f Received: from dea.linux-mips.net (shaft16-f207.dialo.tiscali.de [62.246.16.207]) by oss.sgi.com (8.12.5/8.12.5) with SMTP id g6V0UKRw012116 for ; Tue, 30 Jul 2002 17:30:22 -0700 Received: (from ralf@localhost) by dea.linux-mips.net (8.11.6/8.11.6) id g6V0Ve503371; Wed, 31 Jul 2002 02:31:40 +0200 Date: Wed, 31 Jul 2002 02:31:40 +0200 From: Ralf Baechle To: "Zajerko-McKee, Nick" Cc: "Linux-Mips (E-mail)" Subject: Re: GAS 4kc question... Message-ID: <20020731023140.B2142@dea.linux-mips.net> References: <37A3C2F21006D611995100B0D0F9B73CBFE213@tnint11.telogy.design.ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <37A3C2F21006D611995100B0D0F9B73CBFE213@tnint11.telogy.design.ti.com>; from nmckee@telogy.com on Tue, Jul 30, 2002 at 06:28:32PM -0400 X-Spam-Status: No, hits=-4.4 required=5.0 tests=IN_REP_TO version=2.20 X-Spam-Level: Sender: owner-linux-mips@oss.sgi.com Precedence: bulk On Tue, Jul 30, 2002 at 06:28:32PM -0400, Zajerko-McKee, Nick wrote: > I'm trying to write some inline assembler code that needs the madd and mulu > op codes found on the 4KC processor. I've tried setting the cpu to 4650, > but it failed to recognize the mulu instruction. Can someone give me the > magic incantation? I'm running right now GCC 2.95.3 from Montavista. I > guess one way I can attack it for now is to build the op code by hand, but > that is quite dirty, IMHO... That's an inconsistence in the MIPS instruction set. The old two operand multiply instruction exists as both signed and unsigned (mult / multu) but the new-style signed multiply only in an unsigned flavour. In other words, there is no mulu instruction. I guess the reason was that this instruction is mainly used for DSP-style stuff which need signed arithmetics while burning valuable space in the instruction set for a mulu instruction wasn't considered worth the instruction space. Ralf