From owner-freebsd-hackers Wed Aug 21 01:24:57 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id BAA17922 for hackers-outgoing; Wed, 21 Aug 1996 01:24:57 -0700 (PDT) Received: from Campino.Informatik.RWTH-Aachen.DE (campino.Informatik.RWTH-Aachen.DE [137.226.225.2]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id BAA17896 for ; Wed, 21 Aug 1996 01:24:51 -0700 (PDT) Received: from gilberto.physik.rwth-aachen.de (gilberto.physik.rwth-aachen.de [137.226.31.2]) by Campino.Informatik.RWTH-Aachen.DE (RBI-Z-5/8.6.12) with ESMTP id KAA24971; Wed, 21 Aug 1996 10:20:00 +0200 Received: (from kuku@localhost) by gilberto.physik.rwth-aachen.de (8.6.11/8.6.9) id KAA08275; Wed, 21 Aug 1996 10:32:52 +0200 From: Christoph Kukulies Message-Id: <199608210832.KAA08275@gilberto.physik.rwth-aachen.de> Subject: Re: max math performance - how? To: joerg_wunsch@uriah.heep.sax.de Date: Wed, 21 Aug 1996 10:32:51 +0200 (MET DST) Cc: freebsd-hackers@freebsd.org, kuku@gilberto.physik.rwth-aachen.de In-Reply-To: <199608202032.WAA17791@uriah.heep.sax.de> from J Wunsch at "Aug 20, 96 10:32:27 pm" Reply-To: Christoph Kukulies X-Mailer: ELM [version 2.4ME+ PL16 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > As Bruce Evans wrote: > > > 386BSD used libm, which is slow. -current uses msun, which is > > slower, except possibly if it is compiled with option HAVE_FPU. > > Why don't we compile it with this option? I thought the emulator will > serve those folks who don't have an FPU? We could also ship the > non-FPU lib in a separate package in releases, but i think a large > number of machines now come with an FPU as an integral part of their > system, so still defaulting to non-FPU math libs seems a little silly. Another idea comes into mind: (don't know 386 architecture so well though): Assumed you have an FPU inlined libm. Would it be possible to run the emulator through a trap (emulator trap instruction) or intercepting the illegal instruction trap, checking the stack for a valid FPU instruction and pass instruction execution to the emulator in that case. > > -- > cheers, J"org > > joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE > Never trust an operating system you don't have sources for. ;-) > --Chris Christoph P. U. Kukulies kuku@gil.physik.rwth-aachen.de