Date: Sat, 23 Dec 2006 14:50:17 GMT From: Marius Strobl <marius@alchemy.franken.de> To: freebsd-sparc64@FreeBSD.org Subject: Re: sparc64/107130: conversion from long double to long giving incorrect values Message-ID: <200612231450.kBNEoHeO070170@freefall.freebsd.org>
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The following reply was made to PR sparc64/107130; it has been noted by GNATS.
From: Marius Strobl <marius@alchemy.franken.de>
To: Jim White <crewman6@gmail.com>
Cc: freebsd-gnats-submit@freebsd.org
Subject: Re: sparc64/107130: conversion from long double to long giving incorrect values
Date: Sat, 23 Dec 2006 15:28:54 +0100
On Sat, Dec 23, 2006 at 07:54:11AM +0000, Jim White wrote:
>
> >How-To-Repeat:
> #include <stdio.h>
> int main()
> {
> long double i;
> for (i=0;;i=i-1.0)
> printf("%Lf %d %ld %lld %f\n",i,(int)i,(long)i,(long long)i,(double)i);
> return 0;
> }
>
> Sample Output:
> 0.000000 0 0 0 0.000000
> -1.000000 -1 -1 -1 -1.000000
> -2.000000 -2 -1 -1 -2.000000
> -3.000000 -3 -1 -1 -3.000000
> -4.000000 -4 -1 -1 -4.000000
> -5.000000 -5 -1 -1 -5.000000
> -6.000000 -6 -1 -1 -6.000000
> -7.000000 -7 -1 -1 -7.000000
> -8.000000 -8 -1 -1 -8.000000
> -9.000000 -9 -1 -1 -9.000000
> -10.000000 -10 -1 -1 -10.000000
>
This appears to be caused by a typo in the FPU emulation code.
Could you please give the patch below a try (after applying
re-compile and re-install libc, if you're linking your
application statically re-compile it afterwards, too)?
Marius
Index: fpu_implode.c
===================================================================
RCS file: /usr/data/bsd/cvs/fbsd/src/lib/libc/sparc64/fpu/fpu_implode.c,v
retrieving revision 1.6
diff -u -r1.6 fpu_implode.c
--- fpu_implode.c 28 Jul 2004 05:41:05 -0000 1.6
+++ fpu_implode.c 23 Dec 2006 14:20:13 -0000
@@ -277,7 +277,7 @@
if (i >= ((u_int64_t)0x8000000000000000LL + sign))
break;
if (sign)
- i = -1;
+ i = -i;
res[1] = (int)i;
return (i >> 32);
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