1 /* Quad-precision floating point sine on <-pi/4,pi/4>.
2 Copyright (C) 1999 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Jakub Jelinek <jj@ultra.linux.cz>
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19 02111-1307 USA. */
20
21 #include "quadmath-imp.h"
22
23 static const __float128 c[] = {
24 #define ONE c[0]
25 1.00000000000000000000000000000000000E+00Q, /* 3fff0000000000000000000000000000 */
26
27 /* cos x ~ ONE + x^2 ( SCOS1 + SCOS2 * x^2 + ... + SCOS4 * x^6 + SCOS5 * x^8 )
28 x in <0,1/256> */
29 #define SCOS1 c[1]
30 #define SCOS2 c[2]
31 #define SCOS3 c[3]
32 #define SCOS4 c[4]
33 #define SCOS5 c[5]
34 -5.00000000000000000000000000000000000E-01Q, /* bffe0000000000000000000000000000 */
35 4.16666666666666666666666666556146073E-02Q, /* 3ffa5555555555555555555555395023 */
36 -1.38888888888888888888309442601939728E-03Q, /* bff56c16c16c16c16c16a566e42c0375 */
37 2.48015873015862382987049502531095061E-05Q, /* 3fefa01a01a019ee02dcf7da2d6d5444 */
38 -2.75573112601362126593516899592158083E-07Q, /* bfe927e4f5dce637cb0b54908754bde0 */
39
40 /* sin x ~ ONE * x + x^3 ( SIN1 + SIN2 * x^2 + ... + SIN7 * x^12 + SIN8 * x^14 )
41 x in <0,0.1484375> */
42 #define SIN1 c[6]
43 #define SIN2 c[7]
44 #define SIN3 c[8]
45 #define SIN4 c[9]
46 #define SIN5 c[10]
47 #define SIN6 c[11]
48 #define SIN7 c[12]
49 #define SIN8 c[13]
50 -1.66666666666666666666666666666666538e-01Q, /* bffc5555555555555555555555555550 */
51 8.33333333333333333333333333307532934e-03Q, /* 3ff811111111111111111111110e7340 */
52 -1.98412698412698412698412534478712057e-04Q, /* bff2a01a01a01a01a01a019e7a626296 */
53 2.75573192239858906520896496653095890e-06Q, /* 3fec71de3a556c7338fa38527474b8f5 */
54 -2.50521083854417116999224301266655662e-08Q, /* bfe5ae64567f544e16c7de65c2ea551f */
55 1.60590438367608957516841576404938118e-10Q, /* 3fde6124613a811480538a9a41957115 */
56 -7.64716343504264506714019494041582610e-13Q, /* bfd6ae7f3d5aef30c7bc660b060ef365 */
57 2.81068754939739570236322404393398135e-15Q, /* 3fce9510115aabf87aceb2022a9a9180 */
58
59 /* sin x ~ ONE * x + x^3 ( SSIN1 + SSIN2 * x^2 + ... + SSIN4 * x^6 + SSIN5 * x^8 )
60 x in <0,1/256> */
61 #define SSIN1 c[14]
62 #define SSIN2 c[15]
63 #define SSIN3 c[16]
64 #define SSIN4 c[17]
65 #define SSIN5 c[18]
66 -1.66666666666666666666666666666666659E-01Q, /* bffc5555555555555555555555555555 */
67 8.33333333333333333333333333146298442E-03Q, /* 3ff81111111111111111111110fe195d */
68 -1.98412698412698412697726277416810661E-04Q, /* bff2a01a01a01a01a019e7121e080d88 */
69 2.75573192239848624174178393552189149E-06Q, /* 3fec71de3a556c640c6aaa51aa02ab41 */
70 -2.50521016467996193495359189395805639E-08Q, /* bfe5ae644ee90c47dc71839de75b2787 */
71 };
72
73 #define SINCOSQ_COS_HI 0
74 #define SINCOSQ_COS_LO 1
75 #define SINCOSQ_SIN_HI 2
76 #define SINCOSQ_SIN_LO 3
77 extern const __float128 __sincosq_table[];
78
79 __float128
__quadmath_kernel_sinq(__float128 x,__float128 y,int iy)80 __quadmath_kernel_sinq (__float128 x, __float128 y, int iy)
81 {
82 __float128 h, l, z, sin_l, cos_l_m1;
83 int64_t ix;
84 uint32_t tix, hix, index;
85 GET_FLT128_MSW64 (ix, x);
86 tix = ((uint64_t)ix) >> 32;
87 tix &= ~0x80000000; /* tix = |x|'s high 32 bits */
88 if (tix < 0x3ffc3000) /* |x| < 0.1484375 */
89 {
90 /* Argument is small enough to approximate it by a Chebyshev
91 polynomial of degree 17. */
92 if (tix < 0x3fc60000) /* |x| < 2^-57 */
93 {
94 math_check_force_underflow (x);
95 if (!((int)x)) return x; /* generate inexact */
96 }
97 z = x * x;
98 return x + (x * (z*(SIN1+z*(SIN2+z*(SIN3+z*(SIN4+
99 z*(SIN5+z*(SIN6+z*(SIN7+z*SIN8)))))))));
100 }
101 else
102 {
103 /* So that we don't have to use too large polynomial, we find
104 l and h such that x = l + h, where fabsl(l) <= 1.0/256 with 83
105 possible values for h. We look up cosq(h) and sinq(h) in
106 pre-computed tables, compute cosq(l) and sinq(l) using a
107 Chebyshev polynomial of degree 10(11) and compute
108 sinq(h+l) = sinq(h)cosq(l) + cosq(h)sinq(l). */
109 index = 0x3ffe - (tix >> 16);
110 hix = (tix + (0x200 << index)) & (0xfffffc00 << index);
111 x = fabsq (x);
112 switch (index)
113 {
114 case 0: index = ((45 << 10) + hix - 0x3ffe0000) >> 8; break;
115 case 1: index = ((13 << 11) + hix - 0x3ffd0000) >> 9; break;
116 default:
117 case 2: index = (hix - 0x3ffc3000) >> 10; break;
118 }
119
120 SET_FLT128_WORDS64(h, ((uint64_t)hix) << 32, 0);
121 if (iy)
122 l = (ix < 0 ? -y : y) - (h - x);
123 else
124 l = x - h;
125 z = l * l;
126 sin_l = l*(ONE+z*(SSIN1+z*(SSIN2+z*(SSIN3+z*(SSIN4+z*SSIN5)))));
127 cos_l_m1 = z*(SCOS1+z*(SCOS2+z*(SCOS3+z*(SCOS4+z*SCOS5))));
128 z = __sincosq_table [index + SINCOSQ_SIN_HI]
129 + (__sincosq_table [index + SINCOSQ_SIN_LO]
130 + (__sincosq_table [index + SINCOSQ_SIN_HI] * cos_l_m1)
131 + (__sincosq_table [index + SINCOSQ_COS_HI] * sin_l));
132 return (ix < 0) ? -z : z;
133 }
134 }
135