From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jakub Jelinek To: frichard@bbn.com Cc: egcs@cygnus.com Subject: Re: More info: EGCS-971016 on Solaris2.5/UltraSparc Date: Tue, 21 Oct 1997 00:30:00 -0000 Message-id: <199710210731.JAA00622@sunsite.ms.mff.cuni.cz> References: <199710202229.SAA13564@bbn.com> X-SW-Source: 1997-10/msg00902.html > Hi- > > I ran a bunch of tests with the sun CC compiler and I found out that > the only significant feature (for my platform) that their compiler > uses that's not in EGCS (yet) is is the -fns option: > > -fns Turn on the SPARC nonstandard floating-point mode (SPARC) > > Does anyone know what this is? I don't know if this is a trivial > thing or a tricky one. The FPU on the UltraSPARC is not working with subnormal operands and/or results. Instead of that, it traps to the operating system, so that the results can be correct according to IEEE754. That may be slow, so NS says that all subnormal operands and all subnormal results will be replaced by zeros with the same sign (and if requested IEEE754 inexact/underflow traps will be signalled). I'm not 100% sure what does the -fns option in SunPRO exactly, probably it just chooses different startup files and maybe makes some differences in the code. Could you by change sent me privately assembly output of some short FPU intensive program compiled with and without -fns? Cheers, Jakub ___________________________________________________________________ Jakub Jelinek | jj@sunsite.mff.cuni.cz | http://sunsite.mff.cuni.cz Administrator of SunSITE Czech Republic, MFF, Charles University ___________________________________________________________________ Ultralinux - first 64bit OS to take full power of the UltraSparc Linux version 2.0.30 on a sparc machine (291.64 BogoMips). ___________________________________________________________________