diff libquadmath/math/scalbnq.c @ 68:561a7518be6b

update gcc-4.6
author Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
date Sun, 21 Aug 2011 07:07:55 +0900
parents
children 04ced10e8804
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libquadmath/math/scalbnq.c	Sun Aug 21 07:07:55 2011 +0900
@@ -0,0 +1,48 @@
+/* s_scalbnl.c -- long double version of s_scalbn.c.
+ * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
+ */
+   
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+
+#include "quadmath-imp.h"
+
+static const __float128
+two114 = 2.0769187434139310514121985316880384E+34Q, /* 0x4071000000000000, 0 */
+twom114 = 4.8148248609680896326399448564623183E-35Q, /* 0x3F8D000000000000, 0 */
+huge   = 1.0E+4900Q,
+tiny   = 1.0E-4900Q;
+
+__float128
+scalbnq (__float128 x, int n)
+{
+	int64_t k,hx,lx;
+	GET_FLT128_WORDS64(hx,lx,x);
+        k = (hx>>48)&0x7fff;		/* extract exponent */
+        if (k==0) {				/* 0 or subnormal x */
+            if ((lx|(hx&0x7fffffffffffffffULL))==0) return x; /* +-0 */
+	    x *= two114;
+	    GET_FLT128_MSW64(hx,x);
+	    k = ((hx>>48)&0x7fff) - 114;
+	}
+        if (k==0x7fff) return x+x;		/* NaN or Inf */
+        k = k+n;
+        if (n> 50000 || k > 0x7ffe)
+	  return huge*copysignq(huge,x); /* overflow  */
+	if (n< -50000) return tiny*copysignq(tiny,x); /*underflow*/
+        if (k > 0) 				/* normal result */
+	    {SET_FLT128_MSW64(x,(hx&0x8000ffffffffffffULL)|(k<<48)); return x;}
+        if (k <= -114)
+	  return tiny*copysignq(tiny,x); 	/*underflow*/
+        k += 114;				/* subnormal result */
+	SET_FLT128_MSW64(x,(hx&0x8000ffffffffffffULL)|(k<<48));
+        return x*twom114;
+}