Date: Thu, 30 Mar 2000 04:50:02 +1000 (EST) From: Bruce Evans <bde@zeta.org.au> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: Gary Jennejohn <garyj@muc.de>, freebsd-current@FreeBSD.ORG Subject: Re: Very weird assembly failure (was Re: UP kernel performance and Matt Dillon's patches) Message-ID: <Pine.BSF.4.21.0003300445010.2406-100000@alphplex.bde.org> In-Reply-To: <200003291607.IAA63043@apollo.backplane.com>
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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
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