Mercurial > mxe-octave
view src/build-msvctools/math/asinh.c @ 3061:f8299bb6c872
Initial support for native MSVC compilation.
* add MSVC support files: compiler wrappers and support libraries
* adapt libiconv to work with MSVC
* adapt gettext to work with MSVC
author | Michael Goffioul <michael.goffioul@gmail.com> |
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date | Mon, 17 Jun 2013 22:43:11 -0400 |
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#include <math.h> #include <errno.h> #include "fastmath.h" /* asinh(x) = copysign(log(fabs(x) + sqrt(x * x + 1.0)), x) */ double asinh(double x) { double z; if (!isfinite (x)) return x; z = fabs (x); /* Avoid setting FPU underflow exception flag in x * x. */ #if 0 if ( z < 0x1p-32) return x; #endif /* Use log1p to avoid cancellation with small x. Put x * x in denom, so overflow is harmless. asinh(x) = log1p (x + sqrt (x * x + 1.0) - 1.0) = log1p (x + x * x / (sqrt (x * x + 1.0) + 1.0)) */ z = __fast_log1p (z + z * z / (__fast_sqrt (z * z + 1.0) + 1.0)); return ( x > 0.0 ? z : -z); }