1 files changed, 39 insertions, 0 deletions
diff --git a/nuttx/lib/math/lib_tanh.c b/nuttx/lib/math/lib_tanh.c
new file mode 100644
index 000000000..c6a1a1c87
--- /dev/null
+++ b/nuttx/lib/math/lib_tanh.c
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2009, 2010 Nick Johnson <nickbjohnson4224 at gmail.com>
+ * 
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <apps/math.h>
+#include <float.h>
+
+float tanhf(float x) {
+	float x0 = expf(x);
+	float x1 = 1.0 / x0;
+
+	return ((x0 + x1) / (x0 - x1));
+}
+
+double tanh(double x) {
+	double x0 = exp(x);
+	double x1 = 1.0 / x0;
+
+	return ((x0 + x1) / (x0 - x1));
+}
+
+long double tanhl(long double x) {
+	long double x0 = exp(x);
+	long double x1 = 1.0 / x0;
+
+	return ((x0 + x1) / (x0 - x1));
+}