From owner-cvs-all Wed Dec 30 07:20:53 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id HAA24261 for cvs-all-outgoing; Wed, 30 Dec 1998 07:20:53 -0800 (PST) (envelope-from owner-cvs-all@FreeBSD.ORG) Received: from nlsystems.com (nlsys.demon.co.uk [158.152.125.33]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id HAA24249; Wed, 30 Dec 1998 07:20:48 -0800 (PST) (envelope-from dfr@nlsystems.com) Received: from localhost (dfr@localhost) by nlsystems.com (8.9.1/8.8.5) with SMTP id PAA12293; Wed, 30 Dec 1998 15:17:36 GMT Date: Wed, 30 Dec 1998 15:17:35 +0000 (GMT) From: Doug Rabson To: Poul-Henning Kamp cc: Hidetoshi Shimokawa , dfr@FreeBSD.ORG, cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/sys/alpha/alpha vm_machdep.c machdep.c fp_emulate.c trap.c src/sys/alpha/include vmparam.h src/sys/kern init_main.c kern_exec.c src/sys/sys imgact.h In-Reply-To: <87569.915030208@critter.freebsd.dk> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk On Wed, 30 Dec 1998, Poul-Henning Kamp wrote: > In message , Dou > g Rabson writes: > >On Wed, 30 Dec 1998, Hidetoshi Shimokawa wrote: > > > >> dfr> * Disable all floating point exceptions by default. > >> > >> My understanding is that we still get SIGFPE without > >> "-mtrap-precision=i -mfp-trap-mode=su" option of cc and default > >> cc doesn't have this option. Am I right? > > > >That is true (I think). I'm not quite sure what happens if exceptions are > >disabled but an operation generates an underflow. > > Don't you just get denormalized numbers, NaNs and similar monsters ? On the alpha, denorms, INFs and NaNs are not generated by the hardware. If a corner-case expression is evaluated, it can optionally trap to a kernel floating point emulator which can handle all the gory details of overflows and underflows. -- Doug Rabson Mail: dfr@nlsystems.com Nonlinear Systems Ltd. Phone: +44 181 442 9037 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message