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
80
81
82
83
84
85
86
87
88
89
90
91
92
|
/* See the import.pl script for potential modifications */
/* e_acosf.c -- Simple version of e_acos.c.
* Conversion to Simple 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.
* ====================================================
*/
#if defined(LIBM_SCCS) && !defined(lint)
static char rcsid[] = "$NetBSD: e_acosf.c,v 1.5f 1995/05/12 04:57:16 jtc Exp $";
#endif
#include "SMath.h"
#include "math_private.h"
namespace streflop_libm {
#ifdef __STDC__
static const Simple
#else
static Simple
#endif
one = 1.0000000000e+00f, /* 0x3F800000 */
pi = 3.1415925026e+00f, /* 0x40490fda */
pio2_hi = 1.5707962513e+00f, /* 0x3fc90fda */
pio2_lo = 7.5497894159e-08f, /* 0x33a22168 */
pS0 = 1.6666667163e-01f, /* 0x3e2aaaab */
pS1 = -3.2556581497e-01f, /* 0xbea6b090 */
pS2 = 2.0121252537e-01f, /* 0x3e4e0aa8 */
pS3 = -4.0055535734e-02f, /* 0xbd241146 */
pS4 = 7.9153501429e-04f, /* 0x3a4f7f04 */
pS5 = 3.4793309169e-05f, /* 0x3811ef08 */
qS1 = -2.4033949375e+00f, /* 0xc019d139 */
qS2 = 2.0209457874e+00f, /* 0x4001572d */
qS3 = -6.8828397989e-01f, /* 0xbf303361 */
qS4 = 7.7038154006e-02f; /* 0x3d9dc62e */
#ifdef __STDC__
Simple __ieee754_acosf(Simple x)
#else
Simple __ieee754_acosf(x)
Simple x;
#endif
{
Simple z,p,q,r,w,s,c,df;
int32_t hx,ix;
GET_FLOAT_WORD(hx,x);
ix = hx&0x7fffffff;
if(ix==0x3f800000) { /* |x|==1 */
if(hx>0) return 0.0f; /* acos(1) = 0 */
else return pi+(Simple)2.0f*pio2_lo; /* acos(-1)= pi */
} else if(ix>0x3f800000) { /* |x| >= 1 */
return (x-x)/(x-x); /* acos(|x|>1) is NaN */
}
if(ix<0x3f000000) { /* |x| < 0.5f */
if(ix<=0x23000000) return pio2_hi+pio2_lo;/*if|x|<2**-57*/
z = x*x;
p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
r = p/q;
return pio2_hi - (x - (pio2_lo-x*r));
} else if (hx<0) { /* x < -0.5f */
z = (one+x)*(Simple)0.5f;
p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
s = __ieee754_sqrtf(z);
r = p/q;
w = r*s-pio2_lo;
return pi - (Simple)2.0f*(s+w);
} else { /* x > 0.5f */
int32_t idf;
z = (one-x)*(Simple)0.5f;
s = __ieee754_sqrtf(z);
df = s;
GET_FLOAT_WORD(idf,df);
SET_FLOAT_WORD(df,idf&0xfffff000);
c = (z-df*df)/(s+df);
p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
r = p/q;
w = r*s+c;
return (Simple)2.0f*(df+w);
}
}
}
|
