1 files changed, 94 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/e_coshl.c b/sysdeps/libm-ieee754/e_coshl.c
new file mode 100644
index 0000000000..6af846cb2d
--- /dev/null
+++ b/sysdeps/libm-ieee754/e_coshl.c
@@ -0,0 +1,94 @@
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+
+#if defined(LIBM_SCCS) && !defined(lint)
+static char rcsid[] = "$NetBSD: e_cosh.c,v 1.7 1995/05/10 20:44:58 jtc Exp $";
+#endif
+
+/* __ieee754_coshl(x)
+ * Method :
+ * mathematically coshl(x) if defined to be (exp(x)+exp(-x))/2
+ *	1. Replace x by |x| (coshl(x) = coshl(-x)).
+ *	2.
+ *		                                        [ exp(x) - 1 ]^2
+ *	    0        <= x <= ln2/2  :  coshl(x) := 1 + -------------------
+ *			       			           2*exp(x)
+ *
+ *		                                   exp(x) +  1/exp(x)
+ *	    ln2/2    <= x <= 22     :  coshl(x) := -------------------
+ *			       			           2
+ *	    22       <= x <= lnovft :  coshl(x) := expl(x)/2
+ *	    lnovft   <= x <= ln2ovft:  coshl(x) := expl(x/2)/2 * expl(x/2)
+ *	    ln2ovft  <  x	    :  coshl(x) := huge*huge (overflow)
+ *
+ * Special cases:
+ *	coshl(x) is |x| if x is +INF, -INF, or NaN.
+ *	only coshl(0)=1 is exact for finite x.
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const long double one = 1.0, half=0.5, huge = 1.0e4900L;
+#else
+static long double one = 1.0, half=0.5, huge = 1.0e4900L;
+#endif
+
+#ifdef __STDC__
+	long double __ieee754_coshl(long double x)
+#else
+	long double __ieee754_coshl(x)
+	long double x;
+#endif
+{
+	long double t,w;
+	int32_t ex;
+	u_int32_t mx,lx;
+
+    /* High word of |x|. */
+	GET_LDOUBLE_WORDS(ex,mx,lx,x);
+	ex &= 0x7fff;
+
+    /* x is INF or NaN */
+	if(ex==0x7fff) return x*x;
+
+    /* |x| in [0,0.5*ln2], return 1+expm1l(|x|)^2/(2*expl(|x|)) */
+	if(ex < 0x3ffd || (ex == 0x3ffd && mx < 0xb17217f7u)) {
+	    t = __expm1l(fabsl(x));
+	    w = one+t;
+	    if (ex<0x3fbc) return w;	/* cosh(tiny) = 1 */
+	    return one+(t*t)/(w+w);
+	}
+
+    /* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */
+	if (ex < 0x4003 || (ex == 0x4003 && mx < 0xb0000000u)) {
+		t = __ieee754_expl(fabsl(x));
+		return half*t+half/t;
+	}
+
+    /* |x| in [22, ln(maxdouble)] return half*exp(|x|) */
+	if (ex < 0x400c || (ex == 0x400c && mx < 0xb1700000u))
+		return half*__ieee754_expl(fabsl(x));
+
+    /* |x| in [log(maxdouble), overflowthresold] */
+	if (ex < 0x400d
+	    || (ex == 0x400d && (mx < 0xb170b513u
+				  || (mx == 0xb170b513u && lx < 0xa1dfd60cu))))
+	{
+	    w = __ieee754_expl(half*fabsl(x));
+	    t = half*w;
+	    return t*w;
+	}
+
+    /* |x| > overflowthresold, cosh(x) overflow */
+	return huge*huge;
+}