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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 1906 | serge | 1 | #include |
| 2 | #include |
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| 3 | #include "fastmath.h" |
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| 4 | |||
| 5 | /* acosh(x) = log (x + sqrt(x * x - 1)) */ |
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| 6 | float acoshf (float x) |
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| 7 | { |
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| 8 | if (isnan (x)) |
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| 9 | return x; |
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| 10 | if (x < 1.0f) |
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| 11 | { |
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| 12 | errno = EDOM; |
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| 13 | return nan(""); |
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| 14 | } |
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| 15 | |||
| 16 | if (x > 0x1p32f) |
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| 17 | /* Avoid overflow (and unnecessary calculation when |
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| 18 | sqrt (x * x - 1) == x). GCC optimizes by replacing |
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| 19 | the long double M_LN2 const with a fldln2 insn. */ |
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| 20 | return __fast_log (x) + 6.9314718055994530941723E-1L; |
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| 21 | |||
| 22 | /* Since x >= 1, the arg to log will always be greater than |
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| 23 | the fyl2xp1 limit (approx 0.29) so just use logl. */ |
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| 24 | return __fast_log (x + __fast_sqrt((x + 1.0) * (x - 1.0))); |
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| 25 | } |