diff options
Diffstat (limited to 'lib/mlibc/options/ansi/musl-generic-math/tanh.c')
-rw-r--r-- | lib/mlibc/options/ansi/musl-generic-math/tanh.c | 45 |
1 files changed, 0 insertions, 45 deletions
diff --git a/lib/mlibc/options/ansi/musl-generic-math/tanh.c b/lib/mlibc/options/ansi/musl-generic-math/tanh.c deleted file mode 100644 index 20d6dbc..0000000 --- a/lib/mlibc/options/ansi/musl-generic-math/tanh.c +++ /dev/null @@ -1,45 +0,0 @@ -#include "libm.h" - -/* tanh(x) = (exp(x) - exp(-x))/(exp(x) + exp(-x)) - * = (exp(2*x) - 1)/(exp(2*x) - 1 + 2) - * = (1 - exp(-2*x))/(exp(-2*x) - 1 + 2) - */ -double tanh(double x) -{ - union {double f; uint64_t i;} u = {.f = x}; - uint32_t w; - int sign; - double_t t; - - /* x = |x| */ - sign = u.i >> 63; - u.i &= (uint64_t)-1/2; - x = u.f; - w = u.i >> 32; - - if (w > 0x3fe193ea) { - /* |x| > log(3)/2 ~= 0.5493 or nan */ - if (w > 0x40340000) { - /* |x| > 20 or nan */ - /* note: this branch avoids raising overflow */ - t = 1 - 0/x; - } else { - t = expm1(2*x); - t = 1 - 2/(t+2); - } - } else if (w > 0x3fd058ae) { - /* |x| > log(5/3)/2 ~= 0.2554 */ - t = expm1(2*x); - t = t/(t+2); - } else if (w >= 0x00100000) { - /* |x| >= 0x1p-1022, up to 2ulp error in [0.1,0.2554] */ - t = expm1(-2*x); - t = -t/(t+2); - } else { - /* |x| is subnormal */ - /* note: the branch above would not raise underflow in [0x1p-1023,0x1p-1022) */ - FORCE_EVAL((float)x); - t = x; - } - return sign ? -t : t; -} |