1 files changed, 107 insertions, 0 deletions
diff --git a/sysdeps/ieee754/drem.c b/sysdeps/ieee754/drem.c
new file mode 100644
index 0000000000..cab3a04535
--- /dev/null
+++ b/sysdeps/ieee754/drem.c
@@ -0,0 +1,107 @@
+/* Copyright (C) 1992, 1995 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+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., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+/*
+ * Copyright (c) 1985 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted provided
+ * that: (1) source distributions retain this entire copyright notice and
+ * comment, and (2) distributions including binaries display the following
+ * acknowledgement:  ``This product includes software developed by the
+ * University of California, Berkeley and its contributors'' in the
+ * documentation or other materials provided with the distribution and in
+ * all advertising materials mentioning features or use of this software.
+ * Neither the name of the University nor the names of its contributors may
+ * be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#include <ansidecl.h>
+#include <math.h>
+#include <float.h>
+#include "ieee754.h"
+
+/* Return the remainder of X/Y.  */
+double
+DEFUN(__drem, (x, y),
+      double x AND double y)
+{
+  union ieee754_double ux, uy;
+
+  ux.d = x;
+  uy.d = y;
+#define x ux.d
+#define	y uy.d
+
+  uy.ieee.negative = 0;
+
+  if (!__finite (x) || y == 0.0)
+    return NAN;
+  else if (__isnan (y))
+    return y;
+  else if (__isinf (y))
+    return x;
+  else if (uy.ieee.exponent <= 1)
+    {
+      /* Subnormal (or almost subnormal) Y value.  */
+      double b = __scalb (1.0, 54);
+      y *= b;
+      x = __drem (x, y);
+      x *= b;
+      return __drem (x, y) / b;
+    }
+  else if (y >= 1.7e308 / 2)
+    {
+      y /= 2;
+      x /= 2;
+      return __drem (x, y) * 2;
+    }
+  else
+    {
+      union ieee754_double a;
+      double b;
+      unsigned int negative = ux.ieee.negative;
+      a.d = y + y;
+      b = y / 2;
+      ux.ieee.negative = 0;
+      while (x > a.d)
+	{
+	  unsigned short int k = ux.ieee.exponent - a.ieee.exponent;
+	  union ieee754_double tmp;
+	  tmp.d = a.d;
+	  tmp.ieee.exponent += k;
+	  if (x < tmp.d)
+	    --tmp.ieee.exponent;
+	  x -= tmp.d;
+	}
+      if (x > b)
+	{
+	  x -= y;
+	  if (x >= b)
+	    x -= y;
+	}
+      ux.ieee.negative ^= negative;
+      return x;
+    }
+}
+
+weak_alias (__drem, drem)