From owner-cvs-all Tue Jul 18 5:10:35 2000 Delivered-To: cvs-all@freebsd.org Received: from gidora.zeta.org.au (gidora.zeta.org.au [203.26.10.25]) by hub.freebsd.org (Postfix) with SMTP id C730437BDA3 for ; Tue, 18 Jul 2000 05:10:29 -0700 (PDT) (envelope-from bde@zeta.org.au) Received: (qmail 19665 invoked from network); 18 Jul 2000 12:10:21 -0000 Received: from unknown (HELO bde.zeta.org.au) (203.2.228.102) by gidora.zeta.org.au with SMTP; 18 Jul 2000 12:10:21 -0000 Date: Tue, 18 Jul 2000 22:10:15 +1000 (EST) From: Bruce Evans X-Sender: bde@besplex.bde.org To: Marcel Moolenaar Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/i386/include npx.h In-Reply-To: <200007180412.VAA13490@freefall.freebsd.org> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Mon, 17 Jul 2000, Marcel Moolenaar wrote: > marcel 2000/07/17 21:12:19 PDT > > Modified files: (Branch: RELENG_3) > sys/i386/include npx.h > Log: > MFC: change default FPU control word. > > PR: 17984 > > Revision Changes Path > 1.14.2.2 +5 -35 src/sys/i386/include/npx.h Um, this change was intentionally left out of RELENG_3. The bug is in the Linux emulator not keeping up with Linux. The description misdiagnoses the reason for the exception. I think I explained this already, but the explanation is not attached to the PR. In: float f = FLT_MAX; double d; f = f * 2; /* 3 */ d = f; /* 4 */ line 3 causes undefined behaviour due to overflow. RELENG_3 on i386's was configured so that the undefined behaviour causes a trap on the FP instruction following the one that overflowed. This instruction is in line 4, and doesn't exist if line 4 is omitted. Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message