| 1 | /** |
| 2 | * This file has no copyright assigned and is placed in the Public Domain. |
| 3 | * This file is part of the mingw-w64 runtime package. |
| 4 | * No warranty is given; refer to the file DISCLAIMER.PD within this package. |
| 5 | */ |
| 6 | #include <math.h> |
| 7 | #include <errno.h> |
| 8 | #include <float.h> |
| 9 | #include "fastmath.h" |
| 10 | |
| 11 | /* asinh(x) = copysign(log(fabs(x) + sqrt(x * x + 1.0)), x) */ |
| 12 | long double asinhl(long double x) |
| 13 | { |
| 14 | long double z; |
| 15 | if (!isfinite (x)) |
| 16 | return x; |
| 17 | |
| 18 | z = fabsl (x); |
| 19 | |
| 20 | /* Avoid setting FPU underflow exception flag in x * x. */ |
| 21 | #if 0 |
| 22 | if ( z < 0x1p-32) |
| 23 | return x; |
| 24 | #endif |
| 25 | |
| 26 | /* See commentary in asinh */ |
| 27 | const long double asinhCutover = powl(2,LDBL_MAX_EXP/2); |
| 28 | |
| 29 | if (z < asinhCutover) |
| 30 | z = __fast_log1pl (z + z * (z / (__fast_sqrtl (z * z + 1.0) + 1.0))); |
| 31 | else |
| 32 | z = __fast_logl(2) + __fast_logl(z); |
| 33 | return copysignl(z, x); //ensure 0.0 -> 0.0 and -0.0 -> -0.0. |
| 34 | } |