grab s_lrint from glibc for C99

1 files changed, 94 insertions, 0 deletions

diff --git a/libm/s_lrint.c b/libm/s_lrint.c
new file mode 100644
index 000000000..61c521240
--- /dev/null
+++ b/libm/s_lrint.c
@@ -0,0 +1,94 @@
+/* Round argument to nearest integral value according to current rounding
+   direction.
+   Copyright (C) 1997, 2004 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 two52[2] =
+{
+  4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
+ -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
+};
+
+
+libm_hidden_proto(lrint)
+long int
+lrint (double x)
+{
+  int32_t j0;
+  u_int32_t i0,i1;
+  volatile double w;
+  double t;
+  long int result;
+  int sx;
+
+  EXTRACT_WORDS (i0, i1, x);
+  j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
+  sx = i0 >> 31;
+  i0 &= 0xfffff;
+  i0 |= 0x100000;
+
+  if (j0 < 20)
+    {
+      if (j0 < -1)
+	return 0;
+      else
+	{
+	  w = two52[sx] + x;
+	  t = w - two52[sx];
+	  EXTRACT_WORDS (i0, i1, t);
+	  j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
+	  i0 &= 0xfffff;
+	  i0 |= 0x100000;
+
+	  result = i0 >> (20 - j0);
+	}
+    }
+  else if (j0 < (int32_t) (8 * sizeof (long int)) - 1)
+    {
+      if (j0 >= 52)
+	result = ((long int) i0 << (j0 - 20)) | (i1 << (j0 - 52));
+      else
+	{
+	  w = two52[sx] + x;
+	  t = w - two52[sx];
+	  EXTRACT_WORDS (i0, i1, t);
+	  j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
+	  i0 &= 0xfffff;
+	  i0 |= 0x100000;
+
+	  if (j0 == 20)
+	    result = (long int) i0;
+	  else
+	    result = ((long int) i0 << (j0 - 20)) | (i1 >> (52 - j0));
+	}
+    }
+  else
+    {
+      /* The number is too large.  It is left implementation defined
+	 what happens.  */
+      return (long int) x;
+    }
+
+  return sx ? -result : result;
+}
+libm_hidden_def(lrint)