blob: 5b19d12a4eb4cf05f5524426001dc0f0b1ce237f (
plain) (
blame)
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
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
/* Software floating-point emulation.
ilogbl(x, exp)
Copyright (C) 1999-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek (jj@ultra.linux.cz).
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
/* ilogbl(long double x)
* return the binary exponent of non-zero x
* ilogbl(0) = 0x80000001
* ilogbl(inf/NaN) = 0x7fffffff (no signal is raised)
*/
#include "soft-fp.h"
#include "quad.h"
#include <math.h>
int __ieee754_ilogbl (long double x)
{
FP_DECL_EX;
FP_DECL_Q(X);
/*
FP_UNPACK_Q(X, x);
switch (X_c)
{
case FP_CLS_ZERO:
return FP_ILOGB0;
case FP_CLS_NAN:
case FP_CLS_INF:
return FP_ILOGBNAN;
default:
return X_e;
}
*/
FP_UNPACK_RAW_Q(X, x);
switch (X_e)
{
default:
return X_e - _FP_EXPBIAS_Q;
case 0:
#if (2 * _FP_W_TYPE_SIZE) < _FP_FRACBITS_Q
if (_FP_FRAC_ZEROP_4(X))
return FP_ILOGB0;
else
{
_FP_I_TYPE shift;
_FP_FRAC_CLZ_4(shift, X);
shift -= _FP_FRACXBITS_Q;
return X_e - _FP_EXPBIAS_Q - 1 + shift;
}
#else
if (_FP_FRAC_ZEROP_2(X))
return FP_ILOGB0;
else
{
_FP_I_TYPE shift;
_FP_FRAC_CLZ_2(shift, X);
shift -= _FP_FRACXBITS_Q;
return X_e - _FP_EXPBIAS_Q - 1 + shift;
}
#endif
case _FP_EXPBIAS_Q:
return FP_ILOGBNAN;
}
}
|
