1 files changed, 89 insertions, 0 deletions
diff --git a/libm/ldouble/coshl.c b/libm/ldouble/coshl.c
new file mode 100644
index 000000000..46212ae44
--- /dev/null
+++ b/libm/ldouble/coshl.c
@@ -0,0 +1,89 @@
+/*							coshl.c
+ *
+ *	Hyperbolic cosine, long double precision
+ *
+ *
+ *
+ * SYNOPSIS:
+ *
+ * long double x, y, coshl();
+ *
+ * y = coshl( x );
+ *
+ *
+ *
+ * DESCRIPTION:
+ *
+ * Returns hyperbolic cosine of argument in the range MINLOGL to
+ * MAXLOGL.
+ *
+ * cosh(x)  =  ( exp(x) + exp(-x) )/2.
+ *
+ *
+ *
+ * ACCURACY:
+ *
+ *                      Relative error:
+ * arithmetic   domain     # trials      peak         rms
+ *    IEEE     +-10000      30000       1.1e-19     2.8e-20
+ *
+ *
+ * ERROR MESSAGES:
+ *
+ *   message         condition              value returned
+ * cosh overflow    |x| > MAXLOGL+LOGE2L      INFINITYL
+ *
+ *
+ */
+
+
+/*
+Cephes Math Library Release 2.7:  May, 1998
+Copyright 1985, 1991, 1998 by Stephen L. Moshier
+*/
+
+#include <math.h>
+extern long double MAXLOGL, MAXNUML, LOGE2L;
+#ifdef ANSIPROT
+extern long double expl ( long double );
+extern int isnanl ( long double );
+#else
+long double expl(), isnanl();
+#endif
+#ifdef INFINITIES
+extern long double INFINITYL;
+#endif
+#ifdef NANS
+extern long double NANL;
+#endif
+
+long double coshl(x)
+long double x;
+{
+long double y;
+
+#ifdef NANS
+if( isnanl(x) )
+	return(x);
+#endif
+if( x < 0 )
+	x = -x;
+if( x > (MAXLOGL + LOGE2L) )
+	{
+	mtherr( "coshl", OVERFLOW );
+#ifdef INFINITIES
+	return( INFINITYL );
+#else
+	return( MAXNUML );
+#endif
+	}	
+if( x >= (MAXLOGL - LOGE2L) )
+	{
+	y = expl(0.5L * x);
+	y = (0.5L * y) * y;
+	return(y);
+	}
+y = expl(x);
+y = 0.5L * (y + 1.0L / y);
+return( y );
+}