blob: e1402886121b772c94a3e039f53c3a7544e885a4 (
plain)
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
48
|
/* 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;
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;
}
return (long double) (rhx - 1023);
}
long_double_symbol (libm, __logbl, logbl);
|