Add 64-bit optimized s_round.

2 files changed, 81 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 4b1faea4e7..910e188d06 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2009-08-25  Ulrich Drepper  <drepper@redhat.com>
+
+	* sysdeps/ieee754/dbl-64/wordsize-64/s_round.c: New file.
+
 2009-08-25  Joseph Myers  <joseph@codesourcery.com>
 
 	* math/s_fdiml.c (__fdiml): Use fpclassify instead of fpclassifyl.
diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_round.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_round.c
new file mode 100644
index 0000000000..5bd857910c
--- /dev/null
+++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_round.c
@@ -0,0 +1,77 @@
+/* Round double to integer away from zero.
+   Copyright (C) 1997, 2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <math.h>
+
+#include "math_private.h"
+
+
+static const double huge = 1.0e300;
+
+
+double
+__round (double x)
+{
+  int64_t i0, j0;
+
+  EXTRACT_WORDS64 (i0, x);
+  j0 = ((i0 >> 52) & 0x7ff) - 0x3ff;
+  if (__builtin_expect (j0 < 52, 1))
+    {
+      if (j0 < 0)
+	{
+	  if (huge + x > 0.0)
+	    {
+	      i0 &= UINT64_C(0x8000000000000000);
+	      if (j0 == -1)
+		i0 |= UINT64_C(0x3ff0000000000000);
+	    }
+	}
+      else
+	{
+	  uint64_t i = UINT64_C(0x000fffffffffffff) >> j0;
+	  if ((i0 & i) == 0)
+	    /* X is integral.  */
+	    return x;
+	  if (huge + x > 0.0)
+	    {
+	      /* Raise inexact if x != 0.  */
+	      i0 += UINT64_C(0x0008000000000000) >> j0;
+	      i0 &= ~i;
+	    }
+	}
+    }
+  else
+    {
+      if (j0 == 0x400)
+	/* Inf or NaN.  */
+	return x + x;
+      else
+	return x;
+    }
+
+  INSERT_WORDS64 (x, i0);
+  return x;
+}
+weak_alias (__round, round)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__round, __roundl)
+weak_alias (__round, roundl)
+#endif