Date: Sun, 14 Nov 1999 14:14:53 +0100 From: Marcel Moolenaar <marcel@scc.nl> To: Bruce Evans <bde@zeta.org.au> Cc: Martin Cracauer <cracauer@cons.org>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/i386/include signal.h Message-ID: <382EB5CD.823839D6@scc.nl> References: <Pine.BSF.4.10.9911142303390.21828-100000@alphplex.bde.org>
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Bruce Evans wrote: > > On Sun, 14 Nov 1999, Marcel Moolenaar wrote: > > > Martin Cracauer wrote: > > > > > Reserve space for FPU state in struct sigcontext. Fix some style bugs > > > > and comments while there. > > > > > > I still don't like this approach of unstructred allocated space, an > > > array of unnamed bytes. > > > > It's what it says it is: it's a space reservation. If someone actually > > implements saving the FPU state, then he/she is free (IMO) to change the > > reservation into whatever he/she things he/she needs or thinks is > > meaningful. > > Martin implemented saving it before you complicated things by changing > the signal handling :-). You can't expect me to know what patchsets everybody has laying around on their machines :-) > We seem to have missed allocating some necessary space. glibc-2.1.1 has: > > int sc_fpkind; /* FP_NO, FP_387, etc. */ > int sc_fpused; /* If zero, ignore rest of float state. */ > > int at least some declarations of struct sigcontext. I consider that very implementation specific and therefore can't say that it's necessary in any implementation we come up with. In any case, I don't think the kind of FP is context sensitive and needs to be stored in the context itself. Also, there are plenty of bits (and bit combinations) in the total space that can encode whether the context data has any meaning or not and to what degree. If we need to save the context of the GPL math emulator, we still have exactly 1 int32_t left for our own purposes (eg flags :-). -- Marcel Moolenaar mailto:marcel@scc.nl SCC Internetworking & Databases http://www.scc.nl/ The FreeBSD project mailto:marcel@FreeBSD.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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