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-rw-r--r--sysdeps/libm-ieee754/s_scalblnl.c71
1 files changed, 71 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/s_scalblnl.c b/sysdeps/libm-ieee754/s_scalblnl.c
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+++ b/sysdeps/libm-ieee754/s_scalblnl.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 __scalblnl (long double x, long int n)
+#else
+ long double __scalblnl (x,n)
+ long double x; long 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 += 54; /* subnormal result */
+ SET_LDOUBLE_EXP(x,(es&0x8000)|k);
+ return x*twom63;
+}
+weak_alias (__scalblnl, scalblnl)