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m68k: properly implement logbl for Motorola extended float

This commit is contained in:
Andreas Schwab 2012-05-21 21:18:45 +02:00
parent 2eaac33877
commit 41ddd7da3c
2 changed files with 51 additions and 0 deletions
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2
ChangeLog.m68k
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2012-05-21 Andreas Schwab <schwab@linux-m68k.org>
* sysdeps/m68k/m680x0/fpu/s_logbl.c: New file.
* sysdeps/unix/sysv/linux/m68k/m680x0/nptl/libc.abilist: Update.
* sysdeps/unix/sysv/linux/m68k/coldfire/nptl/libc.abilist: Update.

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sysdeps/m68k/m680x0/fpu/s_logbl.c Normal file
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/* s_logbl.c -- long double version of s_logb.c.
* Conversion to long double by Ulrich Drepper,
* Cygnus Support, drepper@cygnus.com.
*/
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
/*
* long double logbl(x)
* IEEE 754 logb. Included to pass IEEE test suite. Not recommend.
* Use ilogb instead.
*/
#include <math.h>
#include <math_private.h>
long double
__logbl (long double x)
{
int32_t es, lx, ix;
GET_LDOUBLE_WORDS (es, ix, lx, x);
es &= 0x7fff; /* exponent */
if ((es | ix | lx) == 0)
return -1.0 / fabsl (x);
if (es == 0x7fff)
return x * x;
if (es == 0) /* IEEE 754 logb */
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
if (ix == 0)
es = -(__builtin_clz (lx) + 32);
else
es = -__builtin_clz (ix);
}
return (long double) (es - 16383);
}
weak_alias (__logbl, logbl)