Last change
on this file since 351 was 337, checked in by coas-nagasima, 6 years ago |
ASP3版ECNLを追加
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Property svn:eol-style
set to
native
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Property svn:mime-type
set to
text/x-csrc;charset=UTF-8
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File size:
653 bytes
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1 | #include "libm.h"
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2 |
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3 | float tanhf(float x)
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4 | {
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5 | union {float f; uint32_t i;} u = {.f = x};
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6 | uint32_t w;
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7 | int sign;
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8 | float t;
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9 |
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10 | /* x = |x| */
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11 | sign = u.i >> 31;
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12 | u.i &= 0x7fffffff;
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13 | x = u.f;
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14 | w = u.i;
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15 |
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16 | if (w > 0x3f0c9f54) {
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17 | /* |x| > log(3)/2 ~= 0.5493 or nan */
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18 | if (w > 0x41200000) {
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19 | /* |x| > 10 */
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20 | t = 1 + 0/x;
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21 | } else {
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22 | t = expm1f(2*x);
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23 | t = 1 - 2/(t+2);
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24 | }
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25 | } else if (w > 0x3e82c578) {
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26 | /* |x| > log(5/3)/2 ~= 0.2554 */
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27 | t = expm1f(2*x);
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28 | t = t/(t+2);
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29 | } else if (w >= 0x00800000) {
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30 | /* |x| >= 0x1p-126 */
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31 | t = expm1f(-2*x);
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32 | t = -t/(t+2);
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33 | } else {
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34 | /* |x| is subnormal */
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35 | FORCE_EVAL(x*x);
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36 | t = x;
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37 | }
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38 | return sign ? -t : t;
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39 | }
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