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/* s_logbf.c -- float version of s_logb.c.
*/
/*
* ====================================================
* 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>
#include <libm-alias-float.h>
#include <fix-int-fp-convert-zero.h>
#include <math-use-builtins.h>
float
__logbf (float x)
{
#if USE_LOGBF_BUILTIN
return __builtin_logbf (x);
#else
int32_t ix, rix;
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 (__glibc_unlikely ((rix = ix >> 23) == 0))
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
rix -= __builtin_clz (ix) - 9;
}
if (FIX_INT_FP_CONVERT_ZERO && rix == 127)
return 0.0f;
return (float) (rix - 127);
#endif /* ! USE_LOGBF_BUILTIN */
}
libm_alias_float (__logb, logb)
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