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#include <sys/cdefs.h>
| 1/*
2 * ====================================================
3 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
4 *
5 * Developed at SunPro, a Sun Microsystems, Inc. business.
6 * Permission to use, copy, modify, and distribute this
7 * software is freely granted, provided that this notice
8 * is preserved.
9 * ====================================================
10 */
11
12#include <sys/cdefs.h>
|
17__FBSDID("$FreeBSD: head/lib/msun/src/e_log10f.c 176451 2008-02-22 02:30:36Z das $");
| 13__FBSDID("$FreeBSD: head/lib/msun/src/e_log2f.c 216211 2010-12-05 22:11:22Z das $");
|
18
19#include "math.h"
20#include "math_private.h"
| 14
15#include "math.h"
16#include "math_private.h"
|
| 17#include "k_logf.h"
|
21
22static const float
23two25 = 3.3554432000e+07, /* 0x4c000000 */
| 18
19static const float
20two25 = 3.3554432000e+07, /* 0x4c000000 */
|
24ivln10 = 4.3429449201e-01, /* 0x3ede5bd9 */
25log10_2hi = 3.0102920532e-01, /* 0x3e9a2080 */
26log10_2lo = 7.9034151668e-07; /* 0x355427db */
| 21ivln2hi = 0x1.716p+0f,
22ivln2lo = -0x1.7135a8fa03d11p-13;
|
27
28static const float zero = 0.0;
29
30float
| 23
24static const float zero = 0.0;
25
26float
|
31__ieee754_log10f(float x)
| 27__ieee754_log2f(float x)
|
32{
| 28{
|
33 float y,z;
| 29 float f,hi,lo;
|
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;
| 30 int32_t i,k,hx;
31
32 GET_FLOAT_WORD(hx,x);
33
34 k=0;
35 if (hx < 0x00800000) { /* x < 2**-126 */
36 if ((hx&0x7fffffff)==0)
37 return -two25/zero; /* log(+-0)=-inf */
38 if (hx<0) return (x-x)/zero; /* log(-#) = NaN */
39 k -= 25; x *= two25; /* subnormal number, scale up x */
40 GET_FLOAT_WORD(hx,x);
41 }
42 if (hx >= 0x7f800000) return x+x;
43 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;
| 44 hx &= 0x007fffff;
45 i = (hx+(0x4afb0d))&0x800000;
46 SET_FLOAT_WORD(x,hx|(i^0x3f800000)); /* normalize x or x/2 */
47 k += (i>>23);
48 f = __kernel_logf(x);
49 x = x - 1;
50 GET_FLOAT_WORD(hx,x);
51 SET_FLOAT_WORD(hi,hx&0xfffff000);
52 lo = x - hi;
53 return (x+f)*ivln2lo + (lo+f)*ivln2hi + hi*ivln2hi + k;
|
54}
| 54}
|