t = 0.5*log1p((x+x)/(one-x));
if(hx>=0) return t; else return -t;
}
+
+/*
+ * wrapper atanh(x)
+ */
+#ifndef _IEEE_LIBM
+double atanh(double x)
+{
+ double z, y;
+ z = __ieee754_atanh(x);
+ if (_LIB_VERSION == _IEEE_ || isnan(x))
+ return z;
+ y = fabs(x);
+ if (y >= 1.0) {
+ if (y > 1.0)
+ return __kernel_standard(x, x, 30); /* atanh(|x|>1) */
+ return __kernel_standard(x, x, 31); /* atanh(|x|==1) */
+ }
+ return z;
+}
+#else
+strong_alias(__ieee754_atanh, atanh)
+#endif
+libm_hidden_def(atanh)