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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/s_scalblnl.c
parent7d58530341304d403a6626d7f7a1913165fe2f32 (diff)
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2.5-18.1
Diffstat (limited to 'sysdeps/ieee754/ldbl-128ibm/s_scalblnl.c')
-rw-r--r--sysdeps/ieee754/ldbl-128ibm/s_scalblnl.c105
1 files changed, 105 insertions, 0 deletions
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_scalblnl.c b/sysdeps/ieee754/ldbl-128ibm/s_scalblnl.c
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index 0000000000..3a1ba07f2c
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+++ b/sysdeps/ieee754/ldbl-128ibm/s_scalblnl.c
@@ -0,0 +1,105 @@
+/* s_scalblnl.c -- long double version of s_scalbln.c.
+ * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.
+ */
+
+/* @(#)s_scalbln.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: $";
+#endif
+
+/*
+ * scalblnl (long double x, long int n)
+ * scalblnl(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"
+#include <math_ldbl_opt.h>
+
+#ifdef __STDC__
+static const long double
+#else
+static long double
+#endif
+twolm54 = 5.55111512312578270212e-17, /* 0x3C90000000000000, 0 */
+huge   = 1.0E+300L,
+tiny   = 1.0E-300L;
+#ifdef __STDC__
+static const double
+#else
+static double
+#endif
+two54 = 1.80143985094819840000e+16, /* 0x4350000000000000 */
+twom54 = 5.55111512312578270212e-17; /* 0x3C90000000000000 */
+
+#ifdef __STDC__
+	long double __scalblnl (long double x, long int n)
+#else
+	long double __scalblnl (x,n)
+	long double x; long int n;
+#endif
+{
+	int64_t k,l,hx,lx;
+	union { int64_t i; double d; } u;
+	GET_LDOUBLE_WORDS64(hx,lx,x);
+	k = (hx>>52)&0x7ff;		/* extract exponent */
+	l = (lx>>52)&0x7ff;
+	if (k==0) {				/* 0 or subnormal x */
+	    if (((hx|lx)&0x7fffffffffffffffULL)==0) return x; /* +-0 */
+	    u.i = hx;
+	    u.d *= two54;
+	    hx = u.i;
+	    k = ((hx>>52)&0x7ff) - 54;
+	}
+	else if (k==0x7ff) return x+x;		/* NaN or Inf */
+	k = k+n;
+	if (n> 50000 || k > 0x7fe)
+	  return huge*__copysignl(huge,x); /* overflow */
+	if (n< -50000) return tiny*__copysignl(tiny,x); /*underflow */
+	if (k > 0) {				/* normal result */
+	    hx = (hx&0x800fffffffffffffULL)|(k<<52);
+	    if ((lx & 0x7fffffffffffffffULL) == 0) { /* low part +-0 */
+	    	SET_LDOUBLE_WORDS64(x,hx,lx);
+	    	return x;
+	    }
+	    if (l == 0) { /* low part subnormal */
+	    	u.i = lx;
+	    	u.d *= two54;
+	    	lx = u.i;
+	    	l = ((lx>>52)&0x7ff) - 54;
+	    }
+	    l = l + n;
+	    if (l > 0)
+		lx = (lx&0x800fffffffffffffULL)|(l<<52);
+	    else if (l <= -54)
+		lx = (lx&0x8000000000000000ULL);
+	    else {
+	    	l += 54;
+	    	u.i = (lx&0x800fffffffffffffULL)|(l<<52);
+	    	u.d *= twom54;
+	    	lx = u.i;
+	    }
+	    SET_LDOUBLE_WORDS64(x,hx,lx);
+	    return x;
+	}
+	if (k <= -54)
+	  return tiny*__copysignl(tiny,x); 	/*underflow*/
+	k += 54;				/* subnormal result */
+	lx &= 0x8000000000000000ULL;
+	SET_LDOUBLE_WORDS64(x,(hx&0x800fffffffffffffULL)|(k<<52),lx);
+	return x*twolm54;
+}
+long_double_symbol (libm, __scalblnl, scalblnl);