From 7ce331c01ce6eb7b3f5c715a38a24359da9c6ee2 Mon Sep 17 00:00:00 2001
From: Eric Andersen <andersen@codepoet.org>
Date: Thu, 22 Nov 2001 14:04:29 +0000
Subject: Totally rework the math library, this time based on the MacOs X math
 library (which is itself based on the math lib from FreeBSD).  -Erik

---
 libm/e_sinh.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 libm/e_sinh.c

(limited to 'libm/e_sinh.c')

diff --git a/libm/e_sinh.c b/libm/e_sinh.c
new file mode 100644
index 000000000..2e5332c11
--- /dev/null
+++ b/libm/e_sinh.c
@@ -0,0 +1,86 @@
+/* @(#)e_sinh.c 5.1 93/09/24 */
+/*
+ * ====================================================
+ * 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_sinh.c,v 1.7 1995/05/10 20:46:13 jtc Exp $";
+#endif
+
+/* __ieee754_sinh(x)
+ * Method : 
+ * mathematically sinh(x) if defined to be (exp(x)-exp(-x))/2
+ *	1. Replace x by |x| (sinh(-x) = -sinh(x)). 
+ *	2. 
+ *		                                    E + E/(E+1)
+ *	    0        <= x <= 22     :  sinh(x) := --------------, E=expm1(x)
+ *			       			        2
+ *
+ *	    22       <= x <= lnovft :  sinh(x) := exp(x)/2 
+ *	    lnovft   <= x <= ln2ovft:  sinh(x) := exp(x/2)/2 * exp(x/2)
+ *	    ln2ovft  <  x	    :  sinh(x) := x*shuge (overflow)
+ *
+ * Special cases:
+ *	sinh(x) is |x| if x is +INF, -INF, or NaN.
+ *	only sinh(0)=0 is exact for finite x.
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const double one = 1.0, shuge = 1.0e307;
+#else
+static double one = 1.0, shuge = 1.0e307;
+#endif
+
+#ifdef __STDC__
+	double __ieee754_sinh(double x)
+#else
+	double __ieee754_sinh(x)
+	double x;
+#endif
+{	
+	double t,w,h;
+	int32_t ix,jx;
+	u_int32_t lx;
+
+    /* High word of |x|. */
+	GET_HIGH_WORD(jx,x);
+	ix = jx&0x7fffffff;
+
+    /* x is INF or NaN */
+	if(ix>=0x7ff00000) return x+x;	
+
+	h = 0.5;
+	if (jx<0) h = -h;
+    /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */
+	if (ix < 0x40360000) {		/* |x|<22 */
+	    if (ix<0x3e300000) 		/* |x|<2**-28 */
+		if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
+	    t = expm1(fabs(x));
+	    if(ix<0x3ff00000) return h*(2.0*t-t*t/(t+one));
+	    return h*(t+t/(t+one));
+	}
+
+    /* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */
+	if (ix < 0x40862E42)  return h*__ieee754_exp(fabs(x));
+
+    /* |x| in [log(maxdouble), overflowthresold] */
+	GET_LOW_WORD(lx,x);
+	if (ix<0x408633CE || (ix==0x408633ce)&&(lx<=(u_int32_t)0x8fb9f87d)) {
+	    w = __ieee754_exp(0.5*fabs(x));
+	    t = h*w;
+	    return t*w;
+	}
+
+    /* |x| > overflowthresold, sinh(x) overflow */
+	return x*shuge;
+}
-- 
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