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Newsgroups: comp.unix.bsd Path: sserve!manuel!munnari.oz.au!mips!mips!darwin.sura.net!uvaarpa!cv3.cv.nrao.edu!laphroaig!cflatter From: cflatter@nrao.edu (Chris Flatters) Subject: Re: Jolitz 386BSD-0.1 -- floating point perform Message-ID: <1992Jul22.152854.27730@nrao.edu> Sender: news@nrao.edu Reply-To: cflatter@nrao.edu Organization: NRAO References: <l6qc51INN1gu@neuro.usc.edu> Date: Wed, 22 Jul 1992 15:28:54 GMT Lines: 22 In article l6qc51INN1gu@neuro.usc.edu, merlin@neuro.usc.edu (merlin) writes: >I have most of the US Army BRLCAD three dimensional CSG modeling and >distributed ray tracing system ported to the Jolitz 386BSD-0.1. But, >I am getting only about one fifth of the floating point performance >previously measured using AT&T pcc and GNU gcc 1.4x on ATT UNIX SYSV. > >Does the compiler default to '387 emulation? Is there some flag which >needs to be set to actually use the coprocessor? Or are there reasons >386BSD-0.1 would exhibit relatively poor floating point performance? The problem is that there is a mismatch between gcc 1.4 and Intel coprocessors. gcc expects floating-point registers while the 80x87s have a stack. This leads to a fairly large performance hit. gcc 2.x can produce optimised code for the 80x87. Is anyone working on porting gcc 2.x to 386BSD? Come to think of it, is there anything that needs to be done to do this (wouldn't the BSD/386 configuration work)? NB: the coprocessor shows up as device psx0 during the bootstrap sequence. If this doesn't show up 386BSD thinks you don't have a coprocessor. Chris Flatters cflatter@nrao.edu