diff options
Diffstat (limited to 'lib/libm/asinhf.c')
| -rw-r--r-- | lib/libm/asinhf.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/lib/libm/asinhf.c b/lib/libm/asinhf.c new file mode 100644 index 0000000000..4bcb3f9a3a --- /dev/null +++ b/lib/libm/asinhf.c @@ -0,0 +1,34 @@ +/*****************************************************************************/ +/*****************************************************************************/ +// asinhf from musl-0.9.15 +/*****************************************************************************/ +/*****************************************************************************/ + +#include "libm.h" + +/* asinh(x) = sign(x)*log(|x|+sqrt(x*x+1)) ~= x - x^3/6 + o(x^5) */ +float asinhf(float x) +{ + union {float f; uint32_t i;} u = {.f = x}; + uint32_t i = u.i & 0x7fffffff; + unsigned s = u.i >> 31; + + /* |x| */ + u.i = i; + x = u.f; + + if (i >= 0x3f800000 + (12<<23)) { + /* |x| >= 0x1p12 or inf or nan */ + x = logf(x) + 0.693147180559945309417232121458176568f; + } else if (i >= 0x3f800000 + (1<<23)) { + /* |x| >= 2 */ + x = logf(2*x + 1/(sqrtf(x*x+1)+x)); + } else if (i >= 0x3f800000 - (12<<23)) { + /* |x| >= 0x1p-12, up to 1.6ulp error in [0.125,0.5] */ + x = log1pf(x + x*x/(sqrtf(x*x+1)+1)); + } else { + /* |x| < 0x1p-12, raise inexact if x!=0 */ + FORCE_EVAL(x + 0x1p120f); + } + return s ? -x : x; +} |