blob: c54928c7b5629d1b9b1840737781cef7cae39569 (
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
|
/* s_logbf.c -- float version of s_logb.c.
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
*/
/*
* ====================================================
* 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.
* ====================================================
*/
#ifndef lint
static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_logbf.c,v 1.8 2005/12/03 11:57:19 bde Exp $";
#endif
#include "math.h"
#include "math_private.h"
static const float
two25 = 3.355443200e+07; /* 0x4c000000 */
float
logbf(float x)
{
int32_t ix;
GET_FLOAT_WORD(ix,x);
ix &= 0x7fffffff; /* high |x| */
if(ix==0) return (float)-1.0/fabsf(x);
if(ix>=0x7f800000) return x*x;
if(ix<0x00800000) {
x *= two25; /* convert subnormal x to normal */
GET_FLOAT_WORD(ix,x);
ix &= 0x7fffffff;
return (float) ((ix>>23)-127-25);
} else
return (float) ((ix>>23)-127);
}
|
