#include "libm.h"

float tanhf(float x)
{
        union {float f; uint32_t i;} u = {.f = x};
        uint32_t w;
        int sign;
        float t;

        /* x = |x| */
        sign = u.i >> 31;
        u.i &= 0x7fffffff;
        x = u.f;
        w = u.i;

        if (w > 0x3f0c9f54) {
                /* |x| > log(3)/2 ~= 0.5493 or nan */
                if (w > 0x41200000) {
                        /* |x| > 10 */
                        t = 1 + 0/x;
                } else {
                        t = expm1f(2*x);
                        t = 1 - 2/(t+2);
                }
        } else if (w > 0x3e82c578) {
                /* |x| > log(5/3)/2 ~= 0.2554 */
                t = expm1f(2*x);
                t = t/(t+2);
        } else if (w >= 0x00800000) {
                /* |x| >= 0x1p-126 */
                t = expm1f(-2*x);
                t = -t/(t+2);
        } else {
                /* |x| is subnormal */
                FORCE_EVAL(x*x);
                t = x;
        }
        return sign ? -t : t;
}