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authorJakub Jelinek <jakub@redhat.com>2007-07-12 18:26:36 +0000
committerJakub Jelinek <jakub@redhat.com>2007-07-12 18:26:36 +0000
commit0ecb606cb6cf65de1d9fc8a919bceb4be476c602 (patch)
tree2ea1f8305970753e4a657acb2ccc15ca3eec8e2c /sysdeps/ieee754/ldbl-128ibm/e_sinhl.c
parent7d58530341304d403a6626d7f7a1913165fe2f32 (diff)
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2.5-18.1
Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/e_sinhl.c')
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diff --git a/sysdeps/ieee754/ldbl-128ibm/e_sinhl.c b/sysdeps/ieee754/ldbl-128ibm/e_sinhl.c
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+/*
+ * ====================================================
+ * 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 long double one = 1.0, shuge = 1.0e307;
+#else
+static long double one = 1.0, shuge = 1.0e307;
+#endif
+
+#ifdef __STDC__
+	long double __ieee754_sinhl(long double x)
+#else
+	long double __ieee754_sinhl(x)
+	long double x;
+#endif
+{
+	long double t,w,h;
+	int64_t ix,jx;
+
+    /* High word of |x|. */
+	GET_LDOUBLE_MSW64(jx,x);
+	ix = jx&0x7fffffffffffffffLL;
+
+    /* x is INF or NaN */
+	if(ix>=0x7ff0000000000000LL) 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 < 0x4036000000000000LL) {	/* |x|<22 */
+	    if (ix<0x3e20000000000000LL) 	/* |x|<2**-29 */
+		if(shuge+x>one) return x;/* sinhl(tiny) = tiny with inexact */
+	    t = __expm1l(fabsl(x));
+	    if(ix<0x3ff0000000000000LL) 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 < 0x40862e42fefa39efLL)  return h*__ieee754_expl(fabsl(x));
+
+    /* |x| in [log(maxdouble), overflowthresold] */
+	if (ix <= 0x408633ce8fb9f87dLL) {
+	    w = __ieee754_expl(0.5*fabsl(x));
+	    t = h*w;
+	    return t*w;
+	}
+
+    /* |x| > overflowthresold, sinh(x) overflow */
+	return x*shuge;
+}