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/* s_logbl.c -- long double version of s_logb.c.
* Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
*/
/*
* ====================================================
* 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>
#include <math_ldbl_opt.h>
long double
__logbl (long double x)
{
int64_t hx, rhx;
double xhi;
long double ret;
xhi = ldbl_high (x);
EXTRACT_WORDS64 (hx, xhi);
hx &= 0x7fffffffffffffffLL; /* high |x| */
if (hx == 0)
return -1.0 / fabs (x);
if (hx >= 0x7ff0000000000000LL)
return x * x;
if (__builtin_expect ((rhx = hx >> 52) == 0, 0))
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
rhx -= __builtin_clzll (hx) - 12;
}
ret = (long double) (rhx - 1023);
/* The test is to avoid logb_downward (0.0) == -0.0. */
return ret == -0.0 ? 0.0 : ret;
}
#ifndef __logbl
long_double_symbol (libm, __logbl, logbl);
#endif
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