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/* s_logbf.c -- float version of s_logb.c.
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@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.
* ====================================================
*/
#include <math.h>
#include <math_private.h>
float
__logbf (float x)
{
int32_t ix, rix;
float ret;
GET_FLOAT_WORD (ix, x);
ix &= 0x7fffffff; /* high |x| */
if (ix == 0)
return (float) -1.0 / fabsf (x);
if (ix >= 0x7f800000)
return x * x;
if (__builtin_expect ((rix = ix >> 23) == 0, 0))
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
rix -= __builtin_clz (ix) - 9;
}
ret = (float) (rix - 127);
/* The test is to avoid logb_downward (0.0) == -0.0. */
return ret == -0.0 ? 0.0 : ret;
}
weak_alias (__logbf, logbf)
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