1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
|
/* s_logbl.c -- long double 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.
* ====================================================
*/
/*
* 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)
|
