Date: Thu, 29 Nov 2001 08:04:44 -0800 (PST) From: John Baldwin <jhb@FreeBSD.org> To: Peter Pentchev <roam@ringlet.net> Cc: freebsd-hackers@FreeBSD.ORG, David Xu <davidx@viasoft.com.cn> Subject: Re: add some constraints in cpufunc.h Message-ID: <XFMail.011129080444.jhb@FreeBSD.org> In-Reply-To: <20011129153238.A782@straylight.oblivion.bg>
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On 29-Nov-01 Peter Pentchev wrote: > On Wed, Nov 21, 2001 at 11:38:35AM -0800, John Baldwin wrote: >> >> On 21-Nov-01 David Xu wrote: >> > 4.4-stable, file sys/i386/include/cpufunc.h, >> > >> > --- cpufunc.h.orig Wed Nov 21 13:35:36 2001 >> > +++ cpufunc.h Wed Nov 21 15:00:12 2001 >> > @@ -72,7 +72,7 @@ >> > { >> > u_int result; >> > >> > - __asm __volatile("bsfl %0,%0" : "=r" (result) : "0" (mask)); >> > + __asm __volatile("bsfl %0,%0" : "=r" (result) : "0" (mask) : >> > "cc"); >> > return (result); >> > } >> > >> > @@ -81,7 +81,7 @@ >> > { >> > u_int result; >> > >> > - __asm __volatile("bsrl %0,%0" : "=r" (result) : "0" (mask)); >> > + __asm __volatile("bsrl %0,%0" : "=r" (result) : "0" (mask) : >> > "cc"); >> > return (result); >> > } >> > >> > @@ -305,7 +305,7 @@ >> > u_int result; >> > >> > __asm __volatile("xorl %0,%0; xchgl %1,%0" >> > - : "=&r" (result) : "m" (*addr)); >> > + : "=&r" (result) : "m" (*addr) : "cc"); >> > return (result); >> > } >> > >> >> Have you had actual bugs as a result of "cc" not being in the constraints? >> >> If so, there's a _lot_ more places that need this. All the atomic ops, for >> example. > > How about PR gnu/32365? I know next to nothing about assembler opcodes, > if "cc" would fix the PR, then the PR is a demonstration of an actual bug. > > G'luck, > Peter That PR is a bug in the actual compiler itself. I do have a rather largish patch of asm constraint fixes all across the sys/i386 tree in the kernel at www.freebsd.org/~jhb/patches/i386_asm.patch that includes these patches among other things. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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