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1 /* origin: FreeBSD /usr/src/lib/msun/ld80/k_tanl.c */ | 1 /* origin: FreeBSD /usr/src/lib/msun/ld80/k_tanl.c */ |
2 /* origin: FreeBSD /usr/src/lib/msun/ld128/k_tanl.c */ | 2 /* origin: FreeBSD /usr/src/lib/msun/ld128/k_tanl.c */ |
3 /* | 3 /* |
4 * ==================================================== | 4 * ==================================================== |
5 * Copyright 2004 Sun Microsystems, Inc. All Rights Reserved. | 5 * Copyright 2004 Sun Microsystems, Inc. All Rights Reserved. |
6 * Copyright (c) 2008 Steven G. Kargl, David Schultz, Bruce D. Evans. | 6 * Copyright (c) 2008 Steven G. Kargl, David Schultz, Bruce D. Evans. |
7 * | 7 * |
8 * Permission to use, copy, modify, and distribute this | 8 * Permission to use, copy, modify, and distribute this |
9 * software is freely granted, provided that this notice | 9 * software is freely granted, provided that this notice |
10 * is preserved. | 10 * is preserved. |
11 * ==================================================== | 11 * ==================================================== |
12 */ | 12 */ |
13 | 13 |
14 #include "libm.h" | 14 #include "libm.h" |
15 | 15 |
16 #if (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384 | 16 #if (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384 |
17 #if LDBL_MANT_DIG == 64 | 17 #if LDBL_MANT_DIG == 64 |
18 /* | 18 /* |
19 * ld80 version of __tan.c. See __tan.c for most comments. | 19 * ld80 version of __tan.c. See __tan.c for most comments. |
20 */ | 20 */ |
21 /* | 21 /* |
22 * Domain [-0.67434, 0.67434], range ~[-2.25e-22, 1.921e-22] | 22 * Domain [-0.67434, 0.67434], range ~[-2.25e-22, 1.921e-22] |
23 * |tan(x)/x - t(x)| < 2**-71.9 | 23 * |tan(x)/x - t(x)| < 2**-71.9 |
24 * | 24 * |
25 * See __cosl.c for more details about the polynomial. | 25 * See __cosl.c for more details about the polynomial. |
26 */ | 26 */ |
27 static const long double | 27 static const long double |
28 T3 = 0.333333333333333333180L, /* 0xaaaaaaaaaaaaaaa5.0p-65 */ | 28 T3 = 0.333333333333333333180L, /* 0xaaaaaaaaaaaaaaa5.0p-65 */ |
29 T5 = 0.133333333333333372290L, /* 0x88888888888893c3.0p-66 */ | 29 T5 = 0.133333333333333372290L, /* 0x88888888888893c3.0p-66 */ |
30 T7 = 0.0539682539682504975744L, /* 0xdd0dd0dd0dc13ba2.0p-68 */ | 30 T7 = 0.0539682539682504975744L, /* 0xdd0dd0dd0dc13ba2.0p-68 */ |
31 pio4 = 0.785398163397448309628L, /* 0xc90fdaa22168c235.0p-64 */ | 31 pio4 = 0.785398163397448309628L, /* 0xc90fdaa22168c235.0p-64 */ |
32 pio4lo = -1.25413940316708300586e-20L; /* -0xece675d1fc8f8cbb.0p-130 */ | 32 pio4lo = -1.25413940316708300586e-20L; /* -0xece675d1fc8f8cbb.0p-130 */ |
33 static const double | 33 static const double T9 = 0.021869488536312216, /* 0x1664f4882cc1c2.0p-58 */ |
34 T9 = 0.021869488536312216, /* 0x1664f4882cc1c2.0p-58 */ | 34 T11 = 0.0088632355256619590, /* 0x1226e355c17612.0p-59 */ |
35 T11 = 0.0088632355256619590, /* 0x1226e355c17612.0p-59 */ | 35 T13 = 0.0035921281113786528, /* 0x1d6d3d185d7ff8.0p-61 */ |
36 T13 = 0.0035921281113786528, /* 0x1d6d3d185d7ff8.0p-61 */ | 36 T15 = 0.0014558334756312418, /* 0x17da354aa3f96b.0p-62 */ |
37 T15 = 0.0014558334756312418, /* 0x17da354aa3f96b.0p-62 */ | 37 T17 = 0.00059003538700862256, /* 0x13559358685b83.0p-63 */ |
38 T17 = 0.00059003538700862256, /* 0x13559358685b83.0p-63 */ | 38 T19 = 0.00023907843576635544, /* 0x1f56242026b5be.0p-65 */ |
39 T19 = 0.00023907843576635544, /* 0x1f56242026b5be.0p-65 */ | 39 T21 = 0.000097154625656538905, /* 0x1977efc26806f4.0p-66 */ |
40 T21 = 0.000097154625656538905, /* 0x1977efc26806f4.0p-66 */ | 40 T23 = 0.000038440165747303162, /* 0x14275a09b3ceac.0p-67 */ |
41 T23 = 0.000038440165747303162, /* 0x14275a09b3ceac.0p-67 */ | 41 T25 = 0.000018082171885432524, /* 0x12f5e563e5487e.0p-68 */ |
42 T25 = 0.000018082171885432524, /* 0x12f5e563e5487e.0p-68 */ | 42 T27 = 0.0000024196006108814377, /* 0x144c0d80cc6896.0p-71 */ |
43 T27 = 0.0000024196006108814377, /* 0x144c0d80cc6896.0p-71 */ | 43 T29 = 0.0000078293456938132840, /* 0x106b59141a6cb3.0p-69 */ |
44 T29 = 0.0000078293456938132840, /* 0x106b59141a6cb3.0p-69 */ | 44 T31 = -0.0000032609076735050182, /* -0x1b5abef3ba4b59.0p-71 */ |
45 T31 = -0.0000032609076735050182, /* -0x1b5abef3ba4b59.0p-71 */ | 45 T33 = 0.0000023261313142559411; /* 0x13835436c0c87f.0p-71 */ |
46 T33 = 0.0000023261313142559411; /* 0x13835436c0c87f.0p-71 */ | 46 #define RPOLY(w) \ |
47 #define RPOLY(w) (T5 + w * (T9 + w * (T13 + w * (T17 + w * (T21 + \ | 47 (T5 + \ |
48 » w * (T25 + w * (T29 + w * T33))))))) | 48 w * (T9 + \ |
49 #define VPOLY(w) (T7 + w * (T11 + w * (T15 + w * (T19 + w * (T23 + \ | 49 w * (T13 + w * (T17 + w * (T21 + w * (T25 + w * (T29 + w * T33))))))) |
50 » w * (T27 + w * T31)))))) | 50 #define VPOLY(w) \ |
| 51 (T7 + w * (T11 + w * (T15 + w * (T19 + w * (T23 + w * (T27 + w * T31)))))) |
51 #elif LDBL_MANT_DIG == 113 | 52 #elif LDBL_MANT_DIG == 113 |
52 /* | 53 /* |
53 * ld128 version of __tan.c. See __tan.c for most comments. | 54 * ld128 version of __tan.c. See __tan.c for most comments. |
54 */ | 55 */ |
55 /* | 56 /* |
56 * Domain [-0.67434, 0.67434], range ~[-3.37e-36, 1.982e-37] | 57 * Domain [-0.67434, 0.67434], range ~[-3.37e-36, 1.982e-37] |
57 * |tan(x)/x - t(x)| < 2**-117.8 (XXX should be ~1e-37) | 58 * |tan(x)/x - t(x)| < 2**-117.8 (XXX should be ~1e-37) |
58 * | 59 * |
59 * See __cosl.c for more details about the polynomial. | 60 * See __cosl.c for more details about the polynomial. |
60 */ | 61 */ |
61 static const long double | 62 static const long double T3 = 0x1.5555555555555555555555555553p-2L, |
62 T3 = 0x1.5555555555555555555555555553p-2L, | 63 T5 = 0x1.1111111111111111111111111eb5p-3L, |
63 T5 = 0x1.1111111111111111111111111eb5p-3L, | 64 T7 = 0x1.ba1ba1ba1ba1ba1ba1ba1b694cd6p-5L, |
64 T7 = 0x1.ba1ba1ba1ba1ba1ba1ba1b694cd6p-5L, | 65 T9 = 0x1.664f4882c10f9f32d6bbe09d8bcdp-6L, |
65 T9 = 0x1.664f4882c10f9f32d6bbe09d8bcdp-6L, | 66 T11 = 0x1.226e355e6c23c8f5b4f5762322eep-7L, |
66 T11 = 0x1.226e355e6c23c8f5b4f5762322eep-7L, | 67 T13 = 0x1.d6d3d0e157ddfb5fed8e84e27b37p-9L, |
67 T13 = 0x1.d6d3d0e157ddfb5fed8e84e27b37p-9L, | 68 T15 = 0x1.7da36452b75e2b5fce9ee7c2c92ep-10L, |
68 T15 = 0x1.7da36452b75e2b5fce9ee7c2c92ep-10L, | 69 T17 = 0x1.355824803674477dfcf726649efep-11L, |
69 T17 = 0x1.355824803674477dfcf726649efep-11L, | 70 T19 = 0x1.f57d7734d1656e0aceb716f614c2p-13L, |
70 T19 = 0x1.f57d7734d1656e0aceb716f614c2p-13L, | 71 T21 = 0x1.967e18afcb180ed942dfdc518d6cp-14L, |
71 T21 = 0x1.967e18afcb180ed942dfdc518d6cp-14L, | 72 T23 = 0x1.497d8eea21e95bc7e2aa79b9f2cdp-15L, |
72 T23 = 0x1.497d8eea21e95bc7e2aa79b9f2cdp-15L, | 73 T25 = 0x1.0b132d39f055c81be49eff7afd50p-16L, |
73 T25 = 0x1.0b132d39f055c81be49eff7afd50p-16L, | 74 T27 = 0x1.b0f72d33eff7bfa2fbc1059d90b6p-18L, |
74 T27 = 0x1.b0f72d33eff7bfa2fbc1059d90b6p-18L, | 75 T29 = 0x1.5ef2daf21d1113df38d0fbc00267p-19L, |
75 T29 = 0x1.5ef2daf21d1113df38d0fbc00267p-19L, | 76 T31 = 0x1.1c77d6eac0234988cdaa04c96626p-20L, |
76 T31 = 0x1.1c77d6eac0234988cdaa04c96626p-20L, | 77 T33 = 0x1.cd2a5a292b180e0bdd701057dfe3p-22L, |
77 T33 = 0x1.cd2a5a292b180e0bdd701057dfe3p-22L, | 78 T35 = 0x1.75c7357d0298c01a31d0a6f7d518p-23L, |
78 T35 = 0x1.75c7357d0298c01a31d0a6f7d518p-23L, | 79 T37 = 0x1.2f3190f4718a9a520f98f50081fcp-24L, |
79 T37 = 0x1.2f3190f4718a9a520f98f50081fcp-24L, | 80 pio4 = 0x1.921fb54442d18469898cc51701b8p-1L, |
80 pio4 = 0x1.921fb54442d18469898cc51701b8p-1L, | 81 pio4lo = 0x1.cd129024e088a67cc74020bbea60p-116L; |
81 pio4lo = 0x1.cd129024e088a67cc74020bbea60p-116L; | |
82 static const double | 82 static const double |
83 T39 = 0.000000028443389121318352,» /* 0x1e8a7592977938.0p-78 */ | 83 T39 = 0.000000028443389121318352, /* 0x1e8a7592977938.0p-78 */ |
84 T41 = 0.000000011981013102001973,» /* 0x19baa1b1223219.0p-79 */ | 84 T41 = 0.000000011981013102001973, /* 0x19baa1b1223219.0p-79 */ |
85 T43 = 0.0000000038303578044958070,» /* 0x107385dfb24529.0p-80 */ | 85 T43 = 0.0000000038303578044958070, /* 0x107385dfb24529.0p-80 */ |
86 T45 = 0.0000000034664378216909893,» /* 0x1dc6c702a05262.0p-81 */ | 86 T45 = 0.0000000034664378216909893, /* 0x1dc6c702a05262.0p-81 */ |
87 T47 = -0.0000000015090641701997785,» /* -0x19ecef3569ebb6.0p-82 */ | 87 T47 = -0.0000000015090641701997785, /* -0x19ecef3569ebb6.0p-82 */ |
88 T49 = 0.0000000029449552300483952,» /* 0x194c0668da786a.0p-81 */ | 88 T49 = 0.0000000029449552300483952, /* 0x194c0668da786a.0p-81 */ |
89 T51 = -0.0000000022006995706097711,» /* -0x12e763b8845268.0p-81 */ | 89 T51 = -0.0000000022006995706097711, /* -0x12e763b8845268.0p-81 */ |
90 T53 = 0.0000000015468200913196612,» /* 0x1a92fc98c29554.0p-82 */ | 90 T53 = 0.0000000015468200913196612, /* 0x1a92fc98c29554.0p-82 */ |
91 T55 = -0.00000000061311613386849674,» /* -0x151106cbc779a9.0p-83 */ | 91 T55 = -0.00000000061311613386849674, /* -0x151106cbc779a9.0p-83 */ |
92 T57 = 1.4912469681508012e-10;» » /* 0x147edbdba6f43a.0p-85 */ | 92 T57 = 1.4912469681508012e-10; /* 0x147edbdba6f43a.0p-85 */ |
93 #define RPOLY(w) (T5 + w * (T9 + w * (T13 + w * (T17 + w * (T21 + \ | 93 #define RPOLY(w) \ |
94 » w * (T25 + w * (T29 + w * (T33 + w * (T37 + w * (T41 + \ | 94 (T5 + \ |
95 » w * (T45 + w * (T49 + w * (T53 + w * T57))))))))))))) | 95 w * (T9 + \ |
96 #define VPOLY(w) (T7 + w * (T11 + w * (T15 + w * (T19 + w * (T23 + \ | 96 w * (T13 + \ |
97 » w * (T27 + w * (T31 + w * (T35 + w * (T39 + w * (T43 + \ | 97 w * (T17 + \ |
98 » w * (T47 + w * (T51 + w * T55)))))))))))) | 98 w * (T21 + \ |
| 99 w * (T25 + \ |
| 100 w * (T29 + \ |
| 101 w * (T33 + \ |
| 102 w * (T37 + \ |
| 103 w * (T41 + \ |
| 104 w * (T45 + \ |
| 105 w * (T49 + \ |
| 106 w * (T53 + \ |
| 107 w * T57))))))))))
))) |
| 108 #define VPOLY(w) \ |
| 109 (T7 + \ |
| 110 w * (T11 + \ |
| 111 w * (T15 + \ |
| 112 w * (T19 + \ |
| 113 w * (T23 + \ |
| 114 w * (T27 + \ |
| 115 w * (T31 + \ |
| 116 w * (T35 + \ |
| 117 w * (T39 + \ |
| 118 w * (T43 + \ |
| 119 w * (T47 + \ |
| 120 w * (T51 + \ |
| 121 w * T55)))))))))))) |
99 #endif | 122 #endif |
100 | 123 |
101 long double __tanl(long double x, long double y, int odd) { | 124 long double __tanl(long double x, long double y, int odd) { |
102 » long double z, r, v, w, s, a, t; | 125 long double z, r, v, w, s, a, t; |
103 » int big, sign; | 126 int big, sign; |
104 | 127 |
105 » big = fabsl(x) >= 0.67434; | 128 big = fabsl(x) >= 0.67434; |
106 » if (big) { | 129 if (big) { |
107 » » sign = 0; | 130 sign = 0; |
108 » » if (x < 0) { | 131 if (x < 0) { |
109 » » » sign = 1; | 132 sign = 1; |
110 » » » x = -x; | 133 x = -x; |
111 » » » y = -y; | 134 y = -y; |
112 » » } | 135 } |
113 » » x = (pio4 - x) + (pio4lo - y); | 136 x = (pio4 - x) + (pio4lo - y); |
114 » » y = 0.0; | 137 y = 0.0; |
115 » } | 138 } |
116 » z = x * x; | 139 z = x * x; |
117 » w = z * z; | 140 w = z * z; |
118 » r = RPOLY(w); | 141 r = RPOLY(w); |
119 » v = z * VPOLY(w); | 142 v = z * VPOLY(w); |
120 » s = z * x; | 143 s = z * x; |
121 » r = y + z * (s * (r + v) + y) + T3 * s; | 144 r = y + z * (s * (r + v) + y) + T3 * s; |
122 » w = x + r; | 145 w = x + r; |
123 » if (big) { | 146 if (big) { |
124 » » s = 1 - 2*odd; | 147 s = 1 - 2 * odd; |
125 » » v = s - 2.0 * (x + (r - w * w / (w + s))); | 148 v = s - 2.0 * (x + (r - w * w / (w + s))); |
126 » » return sign ? -v : v; | 149 return sign ? -v : v; |
127 » } | 150 } |
128 » if (!odd) | 151 if (!odd) |
129 » » return w; | 152 return w; |
130 » /* | 153 /* |
131 » * if allow error up to 2 ulp, simply return | 154 * if allow error up to 2 ulp, simply return |
132 » * -1.0 / (x+r) here | 155 * -1.0 / (x+r) here |
133 » */ | 156 */ |
134 » /* compute -1.0 / (x+r) accurately */ | 157 /* compute -1.0 / (x+r) accurately */ |
135 » z = w; | 158 z = w; |
136 » z = z + 0x1p32 - 0x1p32; | 159 z = z + 0x1p32 - 0x1p32; |
137 » v = r - (z - x); /* z+v = r+x */ | 160 v = r - (z - x); /* z+v = r+x */ |
138 » t = a = -1.0 / w; /* a = -1.0/w */ | 161 t = a = -1.0 / w; /* a = -1.0/w */ |
139 » t = t + 0x1p32 - 0x1p32; | 162 t = t + 0x1p32 - 0x1p32; |
140 » s = 1.0 + t * z; | 163 s = 1.0 + t * z; |
141 » return t + a * (s + t * v); | 164 return t + a * (s + t * v); |
142 } | 165 } |
143 #endif | 166 #endif |
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