From owner-freebsd-current Wed Mar 29 10:52: 7 2000 Delivered-To: freebsd-current@freebsd.org Received: from mailman.zeta.org.au (mailman.zeta.org.au [203.26.10.16]) by hub.freebsd.org (Postfix) with ESMTP id 5F85C37B800 for ; Wed, 29 Mar 2000 10:50:34 -0800 (PST) (envelope-from bde@zeta.org.au) Received: from bde.zeta.org.au (bde.zeta.org.au [203.2.228.102]) by mailman.zeta.org.au (8.8.7/8.8.7) with ESMTP id EAA21738; Thu, 30 Mar 2000 04:56:02 +1000 Date: Thu, 30 Mar 2000 04:50:02 +1000 (EST) From: Bruce Evans X-Sender: bde@alphplex.bde.org To: Matthew Dillon Cc: Gary Jennejohn , freebsd-current@FreeBSD.ORG Subject: Re: Very weird assembly failure (was Re: UP kernel performance and Matt Dillon's patches) In-Reply-To: <200003291607.IAA63043@apollo.backplane.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Wed, 29 Mar 2000, Matthew Dillon wrote: > :Gas notices the problem for "movl $-FOO,%eax": > : z.s: Assembler messages: > : z.s:1: Error: Negative of non-absolute symbol FOO > :Similarly for the a.out case. Complementation is equivalent to negation > :on 2's complement machines, so gas should produce this error for $~FOO too. > > Ok, so who do we send your excellent analysis to at GNU-C? I think > this is a rather serious bug myself since a programmer can make a > simple labelname mistake and get incorrect code instead of an error. Don't know. David O'Brien has been doing most of the GNU contacting. > Also, probably a simple mistake but complement != negation. > I think ~F = -F - 1; I meant that has equivalent complexity. All normal assemblers and object formats handle offsets, so if they can handle "~" then they can probably handle "-". Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message