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Side by Side Diff: fusl/src/math/log10l.c

Issue 1714623002: [fusl] clang-format fusl (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: headers too Created 4 years, 10 months ago
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1 /* origin: OpenBSD /usr/src/lib/libm/src/ld80/e_log10l.c */ 1 /* origin: OpenBSD /usr/src/lib/libm/src/ld80/e_log10l.c */
2 /* 2 /*
3 * Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net> 3 * Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net>
4 * 4 *
5 * Permission to use, copy, modify, and distribute this software for any 5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above 6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies. 7 * copyright notice and this permission notice appear in all copies.
8 * 8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
(...skipping 42 matching lines...) Expand 10 before | Expand all | Expand 10 after
53 * 53 *
54 * ERROR MESSAGES: 54 * ERROR MESSAGES:
55 * 55 *
56 * log singularity: x = 0; returns MINLOG 56 * log singularity: x = 0; returns MINLOG
57 * log domain: x < 0; returns MINLOG 57 * log domain: x < 0; returns MINLOG
58 */ 58 */
59 59
60 #include "libm.h" 60 #include "libm.h"
61 61
62 #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024 62 #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
63 long double log10l(long double x) 63 long double log10l(long double x) {
64 { 64 return log10(x);
65 » return log10(x);
66 } 65 }
67 #elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384 66 #elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
68 /* Coefficients for log(1+x) = x - x**2/2 + x**3 P(x)/Q(x) 67 /* Coefficients for log(1+x) = x - x**2/2 + x**3 P(x)/Q(x)
69 * 1/sqrt(2) <= x < sqrt(2) 68 * 1/sqrt(2) <= x < sqrt(2)
70 * Theoretical peak relative error = 6.2e-22 69 * Theoretical peak relative error = 6.2e-22
71 */ 70 */
72 static const long double P[] = { 71 static const long double P[] = {
73 4.9962495940332550844739E-1L, 72 4.9962495940332550844739E-1L, 1.0767376367209449010438E1L,
74 1.0767376367209449010438E1L, 73 7.7671073698359539859595E1L, 2.5620629828144409632571E2L,
75 7.7671073698359539859595E1L, 74 4.2401812743503691187826E2L, 3.4258224542413922935104E2L,
76 2.5620629828144409632571E2L, 75 1.0747524399916215149070E2L,
77 4.2401812743503691187826E2L,
78 3.4258224542413922935104E2L,
79 1.0747524399916215149070E2L,
80 }; 76 };
81 static const long double Q[] = { 77 static const long double Q[] = {
82 /* 1.0000000000000000000000E0,*/ 78 /* 1.0000000000000000000000E0,*/
83 2.3479774160285863271658E1L, 79 2.3479774160285863271658E1L, 1.9444210022760132894510E2L,
84 1.9444210022760132894510E2L, 80 7.7952888181207260646090E2L, 1.6911722418503949084863E3L,
85 7.7952888181207260646090E2L, 81 2.0307734695595183428202E3L, 1.2695660352705325274404E3L,
86 1.6911722418503949084863E3L, 82 3.2242573199748645407652E2L,
87 2.0307734695595183428202E3L,
88 1.2695660352705325274404E3L,
89 3.2242573199748645407652E2L,
90 }; 83 };
91 84
92 /* Coefficients for log(x) = z + z^3 P(z^2)/Q(z^2), 85 /* Coefficients for log(x) = z + z^3 P(z^2)/Q(z^2),
93 * where z = 2(x-1)/(x+1) 86 * where z = 2(x-1)/(x+1)
94 * 1/sqrt(2) <= x < sqrt(2) 87 * 1/sqrt(2) <= x < sqrt(2)
95 * Theoretical peak relative error = 6.16e-22 88 * Theoretical peak relative error = 6.16e-22
96 */ 89 */
97 static const long double R[4] = { 90 static const long double R[4] = {
98 1.9757429581415468984296E-3L, 91 1.9757429581415468984296E-3L, -7.1990767473014147232598E-1L,
99 -7.1990767473014147232598E-1L, 92 1.0777257190312272158094E1L, -3.5717684488096787370998E1L,
100 1.0777257190312272158094E1L,
101 -3.5717684488096787370998E1L,
102 }; 93 };
103 static const long double S[4] = { 94 static const long double S[4] = {
104 /* 1.00000000000000000000E0L,*/ 95 /* 1.00000000000000000000E0L,*/
105 -2.6201045551331104417768E1L, 96 -2.6201045551331104417768E1L, 1.9361891836232102174846E2L,
106 1.9361891836232102174846E2L, 97 -4.2861221385716144629696E2L,
107 -4.2861221385716144629696E2L,
108 }; 98 };
109 /* log10(2) */ 99 /* log10(2) */
110 #define L102A 0.3125L 100 #define L102A 0.3125L
111 #define L102B -1.1470004336018804786261e-2L 101 #define L102B -1.1470004336018804786261e-2L
112 /* log10(e) */ 102 /* log10(e) */
113 #define L10EA 0.5L 103 #define L10EA 0.5L
114 #define L10EB -6.5705518096748172348871e-2L 104 #define L10EB -6.5705518096748172348871e-2L
115 105
116 #define SQRTH 0.70710678118654752440L 106 #define SQRTH 0.70710678118654752440L
117 107
118 long double log10l(long double x) 108 long double log10l(long double x) {
119 { 109 long double y, z;
120 » long double y, z; 110 int e;
121 » int e;
122 111
123 » if (isnan(x)) 112 if (isnan(x))
124 » » return x; 113 return x;
125 » if(x <= 0.0) { 114 if (x <= 0.0) {
126 » » if(x == 0.0) 115 if (x == 0.0)
127 » » » return -1.0 / (x*x); 116 return -1.0 / (x * x);
128 » » return (x - x) / 0.0; 117 return (x - x) / 0.0;
129 » } 118 }
130 » if (x == INFINITY) 119 if (x == INFINITY)
131 » » return INFINITY; 120 return INFINITY;
132 » /* separate mantissa from exponent */ 121 /* separate mantissa from exponent */
133 » /* Note, frexp is used so that denormal numbers 122 /* Note, frexp is used so that denormal numbers
134 » * will be handled properly. 123 * will be handled properly.
135 » */ 124 */
136 » x = frexpl(x, &e); 125 x = frexpl(x, &e);
137 126
138 » /* logarithm using log(x) = z + z**3 P(z)/Q(z), 127 /* logarithm using log(x) = z + z**3 P(z)/Q(z),
139 » * where z = 2(x-1)/x+1) 128 * where z = 2(x-1)/x+1)
140 » */ 129 */
141 » if (e > 2 || e < -2) { 130 if (e > 2 || e < -2) {
142 » » if (x < SQRTH) { /* 2(2x-1)/(2x+1) */ 131 if (x < SQRTH) { /* 2(2x-1)/(2x+1) */
143 » » » e -= 1; 132 e -= 1;
144 » » » z = x - 0.5; 133 z = x - 0.5;
145 » » » y = 0.5 * z + 0.5; 134 y = 0.5 * z + 0.5;
146 » » } else { /* 2 (x-1)/(x+1) */ 135 } else { /* 2 (x-1)/(x+1) */
147 » » » z = x - 0.5; 136 z = x - 0.5;
148 » » » z -= 0.5; 137 z -= 0.5;
149 » » » y = 0.5 * x + 0.5; 138 y = 0.5 * x + 0.5;
150 » » } 139 }
151 » » x = z / y; 140 x = z / y;
152 » » z = x*x; 141 z = x * x;
153 » » y = x * (z * __polevll(z, R, 3) / __p1evll(z, S, 3)); 142 y = x * (z * __polevll(z, R, 3) / __p1evll(z, S, 3));
154 » » goto done; 143 goto done;
155 » } 144 }
156 145
157 » /* logarithm using log(1+x) = x - .5x**2 + x**3 P(x)/Q(x) */ 146 /* logarithm using log(1+x) = x - .5x**2 + x**3 P(x)/Q(x) */
158 » if (x < SQRTH) { 147 if (x < SQRTH) {
159 » » e -= 1; 148 e -= 1;
160 » » x = 2.0*x - 1.0; 149 x = 2.0 * x - 1.0;
161 » } else { 150 } else {
162 » » x = x - 1.0; 151 x = x - 1.0;
163 » } 152 }
164 » z = x*x; 153 z = x * x;
165 » y = x * (z * __polevll(x, P, 6) / __p1evll(x, Q, 7)); 154 y = x * (z * __polevll(x, P, 6) / __p1evll(x, Q, 7));
166 » y = y - 0.5*z; 155 y = y - 0.5 * z;
167 156
168 done: 157 done:
169 » /* Multiply log of fraction by log10(e) 158 /* Multiply log of fraction by log10(e)
170 » * and base 2 exponent by log10(2). 159 * and base 2 exponent by log10(2).
171 » * 160 *
172 » * ***CAUTION*** 161 * ***CAUTION***
173 » * 162 *
174 » * This sequence of operations is critical and it may 163 * This sequence of operations is critical and it may
175 » * be horribly defeated by some compiler optimizers. 164 * be horribly defeated by some compiler optimizers.
176 » */ 165 */
177 » z = y * (L10EB); 166 z = y * (L10EB);
178 » z += x * (L10EB); 167 z += x * (L10EB);
179 » z += e * (L102B); 168 z += e * (L102B);
180 » z += y * (L10EA); 169 z += y * (L10EA);
181 » z += x * (L10EA); 170 z += x * (L10EA);
182 » z += e * (L102A); 171 z += e * (L102A);
183 » return z; 172 return z;
184 } 173 }
185 #elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384 174 #elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
186 // TODO: broken implementation to make things compile 175 // TODO: broken implementation to make things compile
187 long double log10l(long double x) 176 long double log10l(long double x) {
188 { 177 return log10(x);
189 » return log10(x);
190 } 178 }
191 #endif 179 #endif
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