1 files changed, 66 insertions, 0 deletions
diff --git a/lib/libm/sf_tan.c b/lib/libm/sf_tan.c
new file mode 100644
index 000000000..a9296d8bf
--- /dev/null
+++ b/lib/libm/sf_tan.c
@@ -0,0 +1,66 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * These math functions are taken from newlib-nano-2, the newlib/libm/math
+ * directory, available from https://github.com/32bitmicro/newlib-nano-2.
+ *
+ * Appropriate copyright headers are reproduced below.
+ */
+
+/* sf_tan.c -- float version of s_tan.c.
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice 
+ * is preserved.
+ * ====================================================
+ */
+
+#include "fdlibm.h"
+
+#ifdef __STDC__
+	float tanf(float x)
+#else
+	float tanf(x)
+	float x;
+#endif
+{
+	float y[2],z=0.0;
+	__int32_t n,ix;
+
+	GET_FLOAT_WORD(ix,x);
+
+    /* |x| ~< pi/4 */
+	ix &= 0x7fffffff;
+	if(ix <= 0x3f490fda) return __kernel_tanf(x,z,1);
+
+    /* tan(Inf or NaN) is NaN */
+	else if (!FLT_UWORD_IS_FINITE(ix)) return x-x;		/* NaN */
+
+    /* argument reduction needed */
+	else {
+	    n = __ieee754_rem_pio2f(x,y);
+	    return __kernel_tanf(y[0],y[1],1-((n&1)<<1)); /*   1 -- n even
+							      -1 -- n odd */
+	}
+}
+
+#ifdef _DOUBLE_IS_32BITS
+
+#ifdef __STDC__
+	double tan(double x)
+#else
+	double tan(x)
+	double x;
+#endif
+{
+	return (double) tanf((float) x);
+}
+
+#endif /* defined(_DOUBLE_IS_32BITS) */