sparc64/107130: conversion from long double to long giving incorrect values

[Marius Strobl]

The following reply was made to PR sparc64/107130; it has been noted by GNATS.

From: Marius Strobl <marius at alchemy.franken.de>
To: Jim White <crewman6 at gmail.com>
Cc: freebsd-gnats-submit at 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);