From 885f5974cdf65b59415837ae97f5a14ef1350670 Mon Sep 17 00:00:00 2001 From: Kacper Date: Tue, 9 Dec 2025 19:20:15 +0100 Subject: feat: add gzip and new headers --- lib/libm/atanhf.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 lib/libm/atanhf.c (limited to 'lib/libm/atanhf.c') diff --git a/lib/libm/atanhf.c b/lib/libm/atanhf.c new file mode 100644 index 00000000..d1026974 --- /dev/null +++ b/lib/libm/atanhf.c @@ -0,0 +1,31 @@ +#include "libm.h" + +/* atanh(x) = log((1+x)/(1-x))/2 = log1p(2x/(1-x))/2 ~= x + x^3/3 + o(x^5) */ +float atanhf(float x) +{ + union { + float f; + uint32_t i; + } u = { .f = x }; + unsigned s = u.i >> 31; + float_t y; + + /* |x| */ + u.i &= 0x7fffffff; + y = u.f; + + if (u.i < 0x3f800000 - (1 << 23)) { + if (u.i < 0x3f800000 - (32 << 23)) { + /* handle underflow */ + if (u.i < (1 << 23)) + FORCE_EVAL((float)(y * y)); + } else { + /* |x| < 0.5, up to 1.7ulp error */ + y = 0.5f * log1pf(2 * y + 2 * y * y / (1 - y)); + } + } else { + /* avoid overflow */ + y = 0.5f * log1pf(2 * (y / (1 - y))); + } + return s ? -y : y; +} -- cgit v1.2.3