Last change
on this file since 403 was 337, checked in by coas-nagasima, 6 years ago |
ASP3版ECNLを追加
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Property svn:eol-style
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native
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Property svn:mime-type
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text/x-csrc;charset=UTF-8
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File size:
605 bytes
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1 | #include "libm.h"
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2 |
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3 | #if FLT_EVAL_METHOD==2
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4 | #undef sqrtf
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5 | #define sqrtf sqrtl
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6 | #elif FLT_EVAL_METHOD==1
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7 | #undef sqrtf
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8 | #define sqrtf sqrt
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9 | #endif
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10 |
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11 | /* acosh(x) = log(x + sqrt(x*x-1)) */
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12 | float acoshf(float x)
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13 | {
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14 | union {float f; uint32_t i;} u = {x};
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15 | uint32_t a = u.i & 0x7fffffff;
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16 |
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17 | if (a < 0x3f800000+(1<<23))
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18 | /* |x| < 2, invalid if x < 1 or nan */
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19 | /* up to 2ulp error in [1,1.125] */
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20 | return log1pf(x-1 + sqrtf((x-1)*(x-1)+2*(x-1)));
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21 | if (a < 0x3f800000+(12<<23))
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22 | /* |x| < 0x1p12 */
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23 | return logf(2*x - 1/(x+sqrtf(x*x-1)));
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24 | /* x >= 0x1p12 */
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25 | return logf(x) + 0.693147180559945309417232121458176568f;
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26 | }
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