1 files changed, 104 insertions, 0 deletions
diff --git a/gnu/lib/libgmp/mpn_mod_1.c b/gnu/lib/libgmp/mpn_mod_1.c
new file mode 100644
index 0000000..19fcefd
--- /dev/null
+++ b/gnu/lib/libgmp/mpn_mod_1.c
@@ -0,0 +1,104 @@
+/* mpn_mod_1(dividend_ptr, dividend_size, divisor_limb) --
+   Divide (DIVIDEND_PTR,,DIVIDEND_SIZE) by DIVISOR_LIMB.
+   Return the single-limb remainder.
+   There are no constraints on the value of the divisor.
+
+   QUOT_PTR and DIVIDEND_PTR might point to the same limb.
+
+Copyright (C) 1991, 1992 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+The GNU MP 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 General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with the GNU MP Library; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "longlong.h"
+
+mp_limb
+#ifdef __STDC__
+mpn_mod_1 (mp_srcptr dividend_ptr, mp_size dividend_size,
+	    unsigned long int divisor_limb)
+#else
+mpn_mod_1 (dividend_ptr, dividend_size, divisor_limb)
+     mp_srcptr dividend_ptr;
+     mp_size dividend_size;
+     unsigned long int divisor_limb;
+#endif
+{
+  int normalization_steps;
+  mp_size i;
+  mp_limb n1, n0, r;
+  int dummy;
+
+  /* Botch: Should this be handled at all?  Rely on callers?  */
+  if (dividend_size == 0)
+    return 0;
+
+  if (UDIV_NEEDS_NORMALIZATION)
+    {
+      count_leading_zeros (normalization_steps, divisor_limb);
+      if (normalization_steps != 0)
+	{
+	  divisor_limb <<= normalization_steps;
+
+	  n1 = dividend_ptr[dividend_size - 1];
+	  r = n1 >> (BITS_PER_MP_LIMB - normalization_steps);
+
+	  /* Possible optimization:
+	  if (r == 0
+	      && divisor_limb > ((n1 << normalization_steps)
+				 | (dividend_ptr[dividend_size - 2] >> ...)))
+	    ...one division less...
+	   */
+
+	  for (i = dividend_size - 2; i >= 0; i--)
+	    {
+	      n0 = dividend_ptr[i];
+	      udiv_qrnnd (dummy, r, r,
+			  ((n1 << normalization_steps)
+			   | (n0 >> (BITS_PER_MP_LIMB - normalization_steps))),
+			  divisor_limb);
+	      n1 = n0;
+	    }
+	  udiv_qrnnd (dummy, r, r,
+		      n1 << normalization_steps,
+		      divisor_limb);
+	  return r >> normalization_steps;
+	}
+    }
+
+  /* No normalization needed, either because udiv_qrnnd doesn't require
+     it, or because DIVISOR_LIMB is already normalized.  */
+
+  i = dividend_size - 1;
+  r = dividend_ptr[i];
+
+  if (r >= divisor_limb)
+    {
+      r = 0;
+    }
+  else
+    {
+      i--;
+    }
+
+  for (; i >= 0; i--)
+    {
+      n0 = dividend_ptr[i];
+      udiv_qrnnd (dummy, r, r, n0, divisor_limb);
+    }
+  return r;
+}