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Re: EGCS-1.0.2 pre fails on Spec CPU 95
- To: Bill Broadley <bill at math dot ucdavis dot edu>
- Subject: Re: EGCS-1.0.2 pre fails on Spec CPU 95
- From: Richard Henderson <rth at cygnus dot com>
- Date: Mon, 16 Mar 1998 16:27:36 -0800
- Cc: rth at cygnus dot com, egcs at cygnus dot com
- References: <firstname.lastname@example.org> <199803091938.LAA29969@proto.math.ucdavis.edu>
- Reply-To: Richard Henderson <rth at cygnus dot com>
On Mon, Mar 09, 1998 at 11:38:51AM -0800, Bill Broadley wrote:
> Running '146.wave5'
> Error comparing benchmark '146.wave5'
Turns out this is a problem between the spec test and the i386 fpu.
Having the calculations done at the wrong precision results in
slightly different end results.
There are two solutions: -ffloat-store, which will completely kill
any sort of performance, or changing the rounding mode in the fpu.
I would go for the later. On Linux at least, the attached program
may be compiled with
gcc -O -o libieee-dbl.a libieee-dbl.c
install the result in some convenient directory and add
to your Spec95 config file. Other Intel operating systems will only
require minor modifications, possibly using inline asm rather than a
/* Exceptions masked, round to double. */