===================================================================
RCS file: /home/cvs/OpenXM_contrib/gmp/mpn/generic/Attic/gcd_1.c,v
retrieving revision 1.1.1.2
retrieving revision 1.1.1.3
diff -u -p -r1.1.1.2 -r1.1.1.3
--- OpenXM_contrib/gmp/mpn/generic/Attic/gcd_1.c	2000/09/09 14:12:25	1.1.1.2
+++ OpenXM_contrib/gmp/mpn/generic/Attic/gcd_1.c	2003/08/25 16:06:20	1.1.1.3
@@ -1,6 +1,6 @@
-/* mpn_gcd_1 --
+/* mpn_gcd_1 -- mpn and limb greatest common divisor.
 
-Copyright (C) 1994, 1996, 2000 Free Software Foundation, Inc.
+Copyright 1994, 1996, 2000, 2001 Free Software Foundation, Inc.
 
 This file is part of the GNU MP Library.
 
@@ -23,55 +23,95 @@ MA 02111-1307, USA. */
 #include "gmp-impl.h"
 #include "longlong.h"
 
+
 /* Does not work for U == 0 or V == 0.  It would be tough to make it work for
-   V == 0 since gcd(x,0) = x, and U does not generally fit in an mp_limb_t.  */
+   V == 0 since gcd(x,0) = x, and U does not generally fit in an mp_limb_t.
 
+   The threshold for doing u%v when size==1 will vary by CPU according to
+   the speed of a division and the code generated for the main loop.  Any
+   tuning for this is left to a CPU specific implementation.  */
+
 mp_limb_t
-#if __STDC__
 mpn_gcd_1 (mp_srcptr up, mp_size_t size, mp_limb_t vlimb)
-#else
-mpn_gcd_1 (up, size, vlimb)
-     mp_srcptr up;
-     mp_size_t size;
-     mp_limb_t vlimb;
-#endif
 {
-  mp_limb_t ulimb;
-  unsigned long int u_low_zero_bits, v_low_zero_bits;
+  mp_limb_t      ulimb;
+  unsigned long  zero_bits, u_low_zero_bits;
 
+  ASSERT (size >= 1);
+  ASSERT (vlimb != 0);
+  ASSERT_MPN_NONZERO_P (up, size);
+
+  ulimb = up[0];
+
+  /* Need vlimb odd for modexact, want it odd to get common zeros. */
+  count_trailing_zeros (zero_bits, vlimb);
+  vlimb >>= zero_bits;
+
   if (size > 1)
     {
-      ulimb = mpn_mod_1 (up, size, vlimb);
+      /* Must get common zeros before the mod reduction.  If ulimb==0 then
+	 vlimb already gives the common zeros.  */
+      if (ulimb != 0)
+	{
+	  count_trailing_zeros (u_low_zero_bits, ulimb);
+	  zero_bits = MIN (zero_bits, u_low_zero_bits);
+	}
+
+      ulimb = MPN_MOD_OR_MODEXACT_1_ODD (up, size, vlimb);
       if (ulimb == 0)
-	return vlimb;
+	goto done;
+
+      goto strip_u_maybe;
     }
-  else
-    ulimb = up[0];
 
-  /*  Need to eliminate low zero bits.  */
+  /* size==1, so up[0]!=0 */
   count_trailing_zeros (u_low_zero_bits, ulimb);
   ulimb >>= u_low_zero_bits;
+  zero_bits = MIN (zero_bits, u_low_zero_bits);
 
-  count_trailing_zeros (v_low_zero_bits, vlimb);
-  vlimb >>= v_low_zero_bits;
+  /* make u bigger */
+  if (vlimb > ulimb)
+    MP_LIMB_T_SWAP (ulimb, vlimb);
 
+  /* if u is much bigger than v, reduce using a division rather than
+     chipping away at it bit-by-bit */
+  if ((ulimb >> 16) > vlimb)
+    {
+      ulimb %= vlimb;
+      if (ulimb == 0)
+	goto done;
+      goto strip_u_maybe;
+    }
+
   while (ulimb != vlimb)
     {
+      ASSERT (ulimb & 1);
+      ASSERT (vlimb & 1);
+
       if (ulimb > vlimb)
 	{
 	  ulimb -= vlimb;
 	  do
-	    ulimb >>= 1;
+	    {
+	      ulimb >>= 1;
+	      ASSERT (ulimb != 0);
+	    strip_u_maybe:
+	      ;
+	    }
 	  while ((ulimb & 1) == 0);
 	}
       else /*  vlimb > ulimb.  */
 	{
 	  vlimb -= ulimb;
 	  do
-	    vlimb >>= 1;
+	    {
+	      vlimb >>= 1;
+	      ASSERT (vlimb != 0);
+	    }
 	  while ((vlimb & 1) == 0);
 	}
     }
 
-  return  ulimb << MIN (u_low_zero_bits, v_low_zero_bits);
+ done:
+  return vlimb << zero_bits;
 }