Date: Fri, 17 Oct 2003 16:45:49 -0700 From: Peter Wemm <peter@wemm.org> To: Daniel Eischen <eischen@vigrid.com> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/lib/libpthread/arch/amd64/amd64 context.S Message-ID: <20031017234549.1568A2A7EA@canning.wemm.org> In-Reply-To: <Pine.GSO.4.10.10310171558150.233-100000@pcnet5.pcnet.com>
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Daniel Eischen wrote: > On Fri, 17 Oct 2003, Peter Wemm wrote: > > > peter 2003/10/17 09:30:09 PDT > > > > FreeBSD src repository > > > > Modified files: > > lib/libpthread/arch/amd64/amd64 context.S > > Log: > > Update context code for my last ABI breakage of mcontext. I'm worried > > about the fpu code here. It should be using fxsave/fxrstor instead of > > saving/restoring the control word. The SSE registers are used a lot in > > gcc generated code on amd64. I'm not sure how this all fits together > > though. > > FYI, the arch-dependent save context is called as a result of an > explicit (e.g., pthread_yield) or implicit (e.g., blocking on a > userland lock) context switch. You only need to save as many > registers as you would for a _setjmp() as long as you mark the > context appropriately (mc_flags, mc_fpformat, etc) and respect > these in the restore context function. The MD restore context > needs to be able to handle both contexts passed out from the > kernel (needing full restores) and those generated from the > save context function (perhaps allowing a more minimal restore). Aha! That would explain a few things. Thanks. Cheers, -Peter -- Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com "All of this is for nothing if we don't go to the stars" - JMS/B5
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