gcc/libquadmath/math/logbq.c
Francois-Xavier Coudert 03c02a42c5 Makefile.am (libquadmath_la_SOURCES): Add math/logbq.c.
* Makefile.am (libquadmath_la_SOURCES): Add math/logbq.c.
	* Makefile.in: Regenerate.
	* libquadmath.texi: Document logbq.
	* quadmath.h: Add logbq prototype.
	* quadmath.map: Add logbq.
	* quadmath_weak.h: Add logbq prototype.
	* math/logbq.c: New file

From-SVN: r226748
2015-08-09 08:46:52 +00:00

48 lines
1.2 KiB
C

/* 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 "quadmath-imp.h"
__float128
logbq (__float128 x)
{
int64_t lx, hx, ex;
GET_FLT128_WORDS64 (hx, lx, x);
hx &= 0x7fffffffffffffffLL; /* high |x| */
if ((hx | lx) == 0)
return -1.0 / fabsq (x);
if (hx >= 0x7fff000000000000LL)
return x * x;
if ((ex = hx >> 48) == 0) /* IEEE 754 logb */
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
int ma;
if (hx == 0)
ma = __builtin_clzll (lx) + 64;
else
ma = __builtin_clzll (hx);
ex -= ma - 16;
}
return (__float128) (ex - 16383);
}