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
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
|
/* Quad-precision floating point sine on <-pi/4,pi/4>.
Copyright (C) 1999-2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* The polynomials have not been optimized for extended-precision and
may contain more terms than needed. */
#include <float.h>
#include <math.h>
#include <math_private.h>
#include <math-underflow.h>
/* The polynomials have not been optimized for extended-precision and
may contain more terms than needed. */
static const long double c[] = {
#define ONE c[0]
1.00000000000000000000000000000000000E+00L,
/* cos x ~ ONE + x^2 ( SCOS1 + SCOS2 * x^2 + ... + SCOS4 * x^6 + SCOS5 * x^8 )
x in <0,1/256> */
#define SCOS1 c[1]
#define SCOS2 c[2]
#define SCOS3 c[3]
#define SCOS4 c[4]
#define SCOS5 c[5]
-5.00000000000000000000000000000000000E-01L,
4.16666666666666666666666666556146073E-02L,
-1.38888888888888888888309442601939728E-03L,
2.48015873015862382987049502531095061E-05L,
-2.75573112601362126593516899592158083E-07L,
/* sin x ~ ONE * x + x^3 ( SIN1 + SIN2 * x^2 + ... + SIN7 * x^12 + SIN8 * x^14 )
x in <0,0.1484375> */
#define SIN1 c[6]
#define SIN2 c[7]
#define SIN3 c[8]
#define SIN4 c[9]
#define SIN5 c[10]
#define SIN6 c[11]
#define SIN7 c[12]
#define SIN8 c[13]
-1.66666666666666666666666666666666538e-01L,
8.33333333333333333333333333307532934e-03L,
-1.98412698412698412698412534478712057e-04L,
2.75573192239858906520896496653095890e-06L,
-2.50521083854417116999224301266655662e-08L,
1.60590438367608957516841576404938118e-10L,
-7.64716343504264506714019494041582610e-13L,
2.81068754939739570236322404393398135e-15L,
/* sin x ~ ONE * x + x^3 ( SSIN1 + SSIN2 * x^2 + ... + SSIN4 * x^6 + SSIN5 * x^8 )
x in <0,1/256> */
#define SSIN1 c[14]
#define SSIN2 c[15]
#define SSIN3 c[16]
#define SSIN4 c[17]
#define SSIN5 c[18]
-1.66666666666666666666666666666666659E-01L,
8.33333333333333333333333333146298442E-03L,
-1.98412698412698412697726277416810661E-04L,
2.75573192239848624174178393552189149E-06L,
-2.50521016467996193495359189395805639E-08L,
};
#define SINCOSL_COS_HI 0
#define SINCOSL_COS_LO 1
#define SINCOSL_SIN_HI 2
#define SINCOSL_SIN_LO 3
extern const long double __sincosl_table[];
long double
__kernel_sinl(long double x, long double y, int iy)
{
long double absx, h, l, z, sin_l, cos_l_m1;
int index;
absx = fabsl (x);
if (absx < 0.1484375L)
{
/* Argument is small enough to approximate it by a Chebyshev
polynomial of degree 17. */
if (absx < 0x1p-33L)
{
math_check_force_underflow (x);
if (!((int)x)) return x; /* generate inexact */
}
z = x * x;
return x + (x * (z*(SIN1+z*(SIN2+z*(SIN3+z*(SIN4+
z*(SIN5+z*(SIN6+z*(SIN7+z*SIN8)))))))));
}
else
{
/* So that we don't have to use too large polynomial, we find
l and h such that x = l + h, where fabsl(l) <= 1.0/256 with 83
possible values for h. We look up cosl(h) and sinl(h) in
pre-computed tables, compute cosl(l) and sinl(l) using a
Chebyshev polynomial of degree 10(11) and compute
sinl(h+l) = sinl(h)cosl(l) + cosl(h)sinl(l). */
index = (int) (128 * (absx - (0.1484375L - 1.0L / 256.0L)));
h = 0.1484375L + index / 128.0;
index *= 4;
if (iy)
l = (x < 0 ? -y : y) - (h - absx);
else
l = absx - h;
z = l * l;
sin_l = l*(ONE+z*(SSIN1+z*(SSIN2+z*(SSIN3+z*(SSIN4+z*SSIN5)))));
cos_l_m1 = z*(SCOS1+z*(SCOS2+z*(SCOS3+z*(SCOS4+z*SCOS5))));
z = __sincosl_table [index + SINCOSL_SIN_HI]
+ (__sincosl_table [index + SINCOSL_SIN_LO]
+ (__sincosl_table [index + SINCOSL_SIN_HI] * cos_l_m1)
+ (__sincosl_table [index + SINCOSL_COS_HI] * sin_l));
return (x < 0) ? -z : z;
}
}
|
