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
93
94
95
96
97
98
99
100
101
102
103
|
/* -------------------------------------------------------------- */
/* (C)Copyright 2007,2008, */
/* International Business Machines Corporation */
/* All Rights Reserved. */
/* */
/* Redistribution and use in source and binary forms, with or */
/* without modification, are permitted provided that the */
/* following conditions are met: */
/* */
/* - Redistributions of source code must retain the above copyright*/
/* notice, this list of conditions and the following disclaimer. */
/* */
/* - Redistributions in binary form must reproduce the above */
/* copyright notice, this list of conditions and the following */
/* disclaimer in the documentation and/or other materials */
/* provided with the distribution. */
/* */
/* - Neither the name of IBM Corporation nor the names of its */
/* contributors may be used to endorse or promote products */
/* derived from this software without specific prior written */
/* permission. */
/* */
/* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND */
/* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, */
/* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF */
/* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE */
/* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR */
/* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, */
/* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT */
/* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; */
/* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) */
/* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN */
/* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR */
/* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, */
/* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
/* -------------------------------------------------------------- */
/* PROLOG END TAG zYx */
#ifdef __SPU__
#ifndef _ATAND2_H_
#define _ATAND2_H_ 1
#include <spu_intrinsics.h>
#include "simdmath.h"
#include "recipd2.h"
#include "logd2.h"
#include "acosd2.h"
#include "asind2.h"
#include "sqrtd2.h"
/*
* FUNCTION
* vector double _atand2(vector double x)
*
* DESCRIPTION
* The _atand2 function computes the arc tangent of a vector of values x.
*
* The arc tangent function is computed using the following relations:
* [0, 1] : arcsin(x1/sqrt(spu_add(x1squ + 1 )));
* (1, infinity] : PI/2 + atanf(-1/x)
* [-infinity, 0) : -arcsin(|x|)
*
*/
static __inline vector double _atand2(vector double x)
{
vector double signbit = spu_splats(-0.0);
vector double oned = spu_splats(1.0);
vector double pi2 = spu_splats(SM_PI_2);
vector double xabs, x1;
vector double result;
vector unsigned long long gt1;
xabs = spu_andc(x, signbit);
gt1 = spu_cmpgt(xabs, oned);
/*
* For x > 1, use the relation:
* atan(x) = pi/2 - atan(1/x), x>1
*/
x1 = spu_sel(xabs, _recipd2(xabs), gt1);
vector double x1squ = spu_mul(x1, x1);
result = _asind2(_divd2(x1, _sqrtd2(spu_add(x1squ, oned))));
/*
* For x > 1, use the relation: atan(x) = pi/2 - atan(1/x), x>1
*/
result = spu_sel(result, spu_sub(pi2, result), gt1);
/*
* Antisymmetric function - preserve sign of x in result.
*/
result = spu_sel(result, x, (vec_ullong2)signbit);
return (result);
}
#endif /* _ATAND2_H_ */
#endif /* __SPU__ */
|
