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authorUlrich Drepper <drepper@redhat.com>1999-07-14 00:54:57 +0000
committerUlrich Drepper <drepper@redhat.com>1999-07-14 00:54:57 +0000
commitabfbdde177c3a7155070dda1b2cdc8292054cc26 (patch)
treee021306b596381fbf8311d2b7eb294e918ff17c8 /sysdeps/ieee754/ldbl-96/s_scalbnl.c
parent86421aa57ecfd70963ae66848bd6a6dd3b8e0fe6 (diff)
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Update.
Diffstat (limited to 'sysdeps/ieee754/ldbl-96/s_scalbnl.c')
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diff --git a/sysdeps/ieee754/ldbl-96/s_scalbnl.c b/sysdeps/ieee754/ldbl-96/s_scalbnl.c
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+/* s_scalbnl.c -- long double version of s_scalbn.c.
+ * Conversion to long double by Ulrich Drepper,
+ * Cygnus Support, drepper@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.
+ * ====================================================
+ */
+
+#if defined(LIBM_SCCS) && !defined(lint)
+static char rcsid[] = "$NetBSD: $";
+#endif
+
+/*
+ * scalbnl (long double x, int n)
+ * scalbnl(x,n) returns x* 2**n  computed by  exponent
+ * manipulation rather than by actually performing an
+ * exponentiation or a multiplication.
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const long double
+#else
+static long double
+#endif
+two63   =  4.50359962737049600000e+15,
+twom63  =  1.08420217248550443400e-19,
+huge   = 1.0e+4900L,
+tiny   = 1.0e-4900L;
+
+#ifdef __STDC__
+	long double __scalbnl (long double x, int n)
+#else
+	long double __scalbnl (x,n)
+	long double x; int n;
+#endif
+{
+	int32_t k,es,hx,lx;
+	GET_LDOUBLE_WORDS(es,hx,lx,x);
+        k = es&0x7fff;				/* extract exponent */
+        if (k==0) {				/* 0 or subnormal x */
+            if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
+	    x *= two63;
+	    GET_LDOUBLE_EXP(es,x);
+	    k = (hx&0x7fff) - 63;
+	    }
+        if (k==0x7fff) return x+x;		/* NaN or Inf */
+        k = k+n;
+        if (n> 50000 || k > 0x7ffe)
+	  return huge*__copysignl(huge,x); /* overflow  */
+	if (n< -50000)
+	  return tiny*__copysignl(tiny,x);
+        if (k > 0) 				/* normal result */
+	    {SET_LDOUBLE_EXP(x,(es&0x8000)|k); return x;}
+        if (k <= -63)
+	    return tiny*__copysignl(tiny,x); 	/*underflow*/
+        k += 63;				/* subnormal result */
+	SET_LDOUBLE_EXP(x,(es&0x8000)|k);
+        return x*twom63;
+}
+weak_alias (__scalbnl, scalbnl)