Mercurial > mxe-octave
diff src/build-msvctools/math/asinhf.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> |
|---|---|
| date | Mon, 17 Jun 2013 22:43:11 -0400 |
| parents | |
| children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/build-msvctools/math/asinhf.c Mon Jun 17 22:43:11 2013 -0400 @@ -0,0 +1,28 @@ +#include <math.h> +#include <errno.h> +#include "fastmath.h" + + /* asinh(x) = copysign(log(fabs(x) + sqrt(x * x + 1.0)), x) */ +float asinhf(float x) +{ + float z; + if (!isfinite (x)) + return x; + z = fabsf (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); +}