1/* e_log10f.c -- float version of e_log10.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 */
4
5/*
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8 *
9 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 * Permission to use, copy, modify, and distribute this
11 * software is freely granted, provided that this notice
12 * is preserved.
13 * ====================================================
14 */
15
| 1/* e_log10f.c -- float version of e_log10.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 */
4
5/*
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8 *
9 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 * Permission to use, copy, modify, and distribute this
11 * software is freely granted, provided that this notice
12 * is preserved.
13 * ====================================================
14 */
15
|
16#ifndef lint
17static char rcsid[] = "$FreeBSD: head/lib/msun/src/e_log10f.c 97413 2002-05-28 18:15:04Z alfred $";
18#endif
| 16#include <sys/cdefs.h>
17__FBSDID("$FreeBSD: head/lib/msun/src/e_log10f.c 176451 2008-02-22 02:30:36Z das $");
|
19
20#include "math.h"
21#include "math_private.h"
22
23static const float
24two25 = 3.3554432000e+07, /* 0x4c000000 */
25ivln10 = 4.3429449201e-01, /* 0x3ede5bd9 */
26log10_2hi = 3.0102920532e-01, /* 0x3e9a2080 */
27log10_2lo = 7.9034151668e-07; /* 0x355427db */
28
29static const float zero = 0.0;
30
31float
32__ieee754_log10f(float x)
33{
34 float y,z;
35 int32_t i,k,hx;
36
37 GET_FLOAT_WORD(hx,x);
38
39 k=0;
40 if (hx < 0x00800000) { /* x < 2**-126 */
41 if ((hx&0x7fffffff)==0)
42 return -two25/zero; /* log(+-0)=-inf */
43 if (hx<0) return (x-x)/zero; /* log(-#) = NaN */
44 k -= 25; x *= two25; /* subnormal number, scale up x */
45 GET_FLOAT_WORD(hx,x);
46 }
47 if (hx >= 0x7f800000) return x+x;
48 k += (hx>>23)-127;
49 i = ((u_int32_t)k&0x80000000)>>31;
50 hx = (hx&0x007fffff)|((0x7f-i)<<23);
51 y = (float)(k+i);
52 SET_FLOAT_WORD(x,hx);
53 z = y*log10_2lo + ivln10*__ieee754_logf(x);
54 return z+y*log10_2hi;
55}
| 18
19#include "math.h"
20#include "math_private.h"
21
22static const float
23two25 = 3.3554432000e+07, /* 0x4c000000 */
24ivln10 = 4.3429449201e-01, /* 0x3ede5bd9 */
25log10_2hi = 3.0102920532e-01, /* 0x3e9a2080 */
26log10_2lo = 7.9034151668e-07; /* 0x355427db */
27
28static const float zero = 0.0;
29
30float
31__ieee754_log10f(float x)
32{
33 float y,z;
34 int32_t i,k,hx;
35
36 GET_FLOAT_WORD(hx,x);
37
38 k=0;
39 if (hx < 0x00800000) { /* x < 2**-126 */
40 if ((hx&0x7fffffff)==0)
41 return -two25/zero; /* log(+-0)=-inf */
42 if (hx<0) return (x-x)/zero; /* log(-#) = NaN */
43 k -= 25; x *= two25; /* subnormal number, scale up x */
44 GET_FLOAT_WORD(hx,x);
45 }
46 if (hx >= 0x7f800000) return x+x;
47 k += (hx>>23)-127;
48 i = ((u_int32_t)k&0x80000000)>>31;
49 hx = (hx&0x007fffff)|((0x7f-i)<<23);
50 y = (float)(k+i);
51 SET_FLOAT_WORD(x,hx);
52 z = y*log10_2lo + ivln10*__ieee754_logf(x);
53 return z+y*log10_2hi;
54}
|