blob: 1d81a26fb81e9e107dcc1bf9982e859edc6d2dd5 (
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
49
50
51
52
53
54
55
|
/* s_ilogbl.c -- long double version of s_ilogb.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.
* ====================================================
*/
#if defined(LIBM_SCCS) && !defined(lint)
static char rcsid[] = "$NetBSD: $";
#endif
/* ilogbl(long double x)
* return the binary exponent of non-zero x
* ilogbl(0) = FP_ILOGB0
* ilogbl(NaN) = FP_ILOGBNAN (no signal is raised)
* ilogbl(+-Inf) = INT_MAX (no signal is raised)
*/
#include <limits.h>
#include <math.h>
#include <math_private.h>
int __ieee754_ilogbl (_Float128 x)
{
int64_t hx,lx;
int ix;
GET_LDOUBLE_WORDS64(hx,lx,x);
hx &= 0x7fffffffffffffffLL;
if(hx <= 0x0001000000000000LL) {
if((hx|lx)==0)
return FP_ILOGB0; /* ilogbl(0) = FP_ILOGB0 */
else /* subnormal x */
if(hx==0) {
for (ix = -16431; lx>0; lx<<=1) ix -=1;
} else {
for (ix = -16382, hx<<=15; hx>0; hx<<=1) ix -=1;
}
return ix;
}
else if (hx<0x7fff000000000000LL) return (hx>>48)-0x3fff;
else if (FP_ILOGBNAN != INT_MAX) {
/* ISO C99 requires ilogbl(+-Inf) == INT_MAX. */
if (((hx^0x7fff000000000000LL)|lx) == 0)
return INT_MAX;
}
return FP_ILOGBNAN;
}
|
