Last change
on this file was 389, checked in by coas-nagasima, 5 years ago |
ビルドが通るよう更新
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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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[388] | 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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