about summary refs log tree commit diff
path: root/sysdeps/libm-ieee754/s_lrintf.c
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/libm-ieee754/s_lrintf.c')
-rw-r--r--sysdeps/libm-ieee754/s_lrintf.c78
1 files changed, 78 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/s_lrintf.c b/sysdeps/libm-ieee754/s_lrintf.c
new file mode 100644
index 0000000000..6d74b362f5
--- /dev/null
+++ b/sysdeps/libm-ieee754/s_lrintf.c
@@ -0,0 +1,78 @@
+/* Round argument to nearest integral value according to current rounding
+   direction.
+   Copyright (C) 1997 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 Library General Public License as
+   published by the Free Software Foundation; either version 2 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  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 two23[2] =
+{
+  8.3886080000e+06, /* 0x4B000000 */
+ -8.3886080000e+06, /* 0xCB000000 */
+};
+
+
+long int
+__lrintf (float x)
+{
+  int32_t j0;
+  u_int32_t i, i0;
+  volatile float w;
+  float t;
+  long int result;
+  int sx;
+
+  GET_FLOAT_WORD (i, x);
+
+  sx = i0 >> 31;
+  j0 = ((i0 >> 23) & 0xff) - 0x7f;
+  i0 = i & 0x7fffff;
+  i0 |= 0x800000;
+
+  if (j0 < (int32_t) (sizeof (long int) * 8))
+    {
+      if (j0 < -1)
+	return 0;
+      else if (j0 >= 23)
+	result = (long int) i0 << (j0 - 23);
+      else
+	{
+	  w = two23[sx] + x;
+	  t = w - two23[sx];
+	  GET_FLOAT_WORD (i, t);
+	  i0 = i & 0x7fffff;
+	  i0 |= 0x800000;
+	  j0 = ((i0 >> 23) & 0xff) - 0x7f;
+
+	  result = i0 >> (23 - j0);
+	}
+    }
+  else
+    {
+      /* The number is too large.  It is left implementation defined
+	 what happens.  */
+      return (long int) x;
+    }
+
+  return sx ? -result : result;
+}
+
+weak_alias (__lrintf, lrintf)