Date: Wed, 01 Aug 2001 16:32:50 +0000 From: "Lee Harr" <missive@hotmail.com> To: freebsd-questions@FreeBSD.org Subject: Fwd: Re: [GENERAL] Re: Better backtrace (wasRe: pqReadData() -- backend closed t Message-ID: <F196ujS410wSgrOAvO80000c91d@hotmail.com>
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Hi:
I was having trouble running PostgreSQL on a Compaq 486 running
FreeBSD 4.3-RELEASE. Tom Lane of the postgres project was kind
enough to take a look at the problem and this is what he found:
>Well, the bottom line seems to be that there's something broken about
>the floating-point support on that box. Look in
>/usr/local/pgsql/data/tmp --- I made a trivial test program that just
>tries to convert a short integer to a double. I get:
>
> > cat tryit.c
>#include <stdio.h>
>#include <stdlib.h>
>
>int main()
>{
> short i = 22;
> double d;
>
> d = i;
>
> printf("i = %d, d = %g\n", i, d);
> return 0;
>}
>
> > gcc tryit.c
> > ./a.out
>Illegal instruction (core dumped)
> > gcc -msoft-float tryit.c
> > ./a.out
>i = 22, d = 22
> > uname -a
>FreeBSD jc12.easthighschool.net 4.3-RELEASE FreeBSD 4.3-RELEASE #0: Sat Apr
>21 10:54:49 GMT 2001 jkh@narf.osd.bsdi.com:/usr/src/sys/compile/GENERIC
> i386
> > gcc -v
>Using builtin specs.
>gcc version 2.95.3 [FreeBSD] 20010315 (release)
> >
>
>I speculate that your box is so old that it has no hardware floating
>point at all, and that what we are seeing here is a fault in FreeBSD's
>software emulation of the 'fild' (short-to-double) instruction. Or
>maybe it's an assembly-time problem. A google search turned up
>
>http://gatekeeper.dec.com/pub/BSD/FreeBSD/FreeBSD-current/src/contrib/binutils/include/opcode/ChangeLog
>
>with the following interesting entry:
>
> 2000-05-17 Maciej W. Rozycki <macro@ds2.pg.gda.pl>
>
> * i386.h: Use sl_FP, not sl_Suf for fild.
>
>which suggests that older versions of the GNU toolchain may mis-assemble
>'fild' instructions.
>
>It'd be worth asking around in BSD-specific mailing lists to see if this
>is a known problem; I didn't find anything else in my web search, but I
>wasn't trying very hard. I think Postgres is off the hook, in any case.
>
> regards, tom lane
I don't know if this is helpful information, or a known issue, but
I figured I should ask before I throw this old box on the scrap heap.
Lee Harr
missive@hotmail.com
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