35 lines
879 B
C
35 lines
879 B
C
/**
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* This file has no copyright assigned and is placed in the Public Domain.
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* This file is part of the mingw-w64 runtime package.
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* No warranty is given; refer to the file DISCLAIMER.PD within this package.
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*/
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#include <math.h>
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#include <errno.h>
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#include <float.h>
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#include "fastmath.h"
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/* asinh(x) = copysign(log(fabs(x) + sqrt(x * x + 1.0)), x) */
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long double asinhl(long double x)
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{
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long double z;
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if (!isfinite (x))
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return x;
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z = fabsl (x);
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/* Avoid setting FPU underflow exception flag in x * x. */
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#if 0
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if ( z < 0x1p-32)
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return x;
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#endif
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/* See commentary in asinh */
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const long double asinhCutover = powl(2,LDBL_MAX_EXP/2);
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if (z < asinhCutover)
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z = __fast_log1pl (z + z * (z / (__fast_sqrtl (z * z + 1.0) + 1.0)));
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else
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z = __fast_logl(2) + __fast_logl(z);
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return copysignl(z, x); //ensure 0.0 -> 0.0 and -0.0 -> -0.0.
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}
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