===================================================================
RCS file: /home/cvs/OpenXM_contrib/gmp/mpz/Attic/scan1.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/mpz/Attic/scan1.c	2000/09/09 14:12:57	1.1.1.2
+++ OpenXM_contrib/gmp/mpz/Attic/scan1.c	2003/08/25 16:06:33	1.1.1.3
@@ -1,6 +1,6 @@
-/* mpz_scan1(op, startbit) -- Scan for the next set bit, starting at startbit.
+/* mpz_scan1 -- search for a 1 bit.
 
-Copyright (C) 1996 Free Software Foundation, Inc.
+Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
 
 This file is part of the GNU MP Library.
 
@@ -21,15 +21,122 @@ MA 02111-1307, USA. */
 
 #include "gmp.h"
 #include "gmp-impl.h"
+#include "longlong.h"
 
-unsigned long int
-#if __STDC__
-mpz_scan1 (mpz_srcptr u, unsigned long int starting_bit)
-#else
-mpz_scan1 (u, starting_bit)
-     mpz_srcptr u;
-     unsigned long int starting_bit;
-#endif
+
+/* mpn_scan0 can't be used for the inverted u<0 search since there might not
+   be a 0 bit before the end of the data.  mpn_scan1 could be used under u>0
+   (except when in the high limb), but usually the search won't go very far
+   so it seems reasonable to inline that code.  */
+
+unsigned long
+mpz_scan1 (mpz_srcptr u, unsigned long starting_bit)
 {
-  return mpn_scan1 (u->_mp_d, starting_bit);
+  mp_srcptr      u_ptr = PTR(u);
+  mp_size_t      size = SIZ(u);
+  mp_size_t      abs_size = ABS(size);
+  mp_srcptr      u_end = u_ptr + abs_size;
+  unsigned long  starting_limb = starting_bit / GMP_NUMB_BITS;
+  mp_srcptr      p = u_ptr + starting_limb;
+  mp_limb_t      limb;
+  int            cnt;
+
+  /* Past the end there's no 1 bits for u>=0, or an immediate 1 bit for u<0.
+     Notice this test picks up any u==0 too. */
+  if (starting_limb >= abs_size)
+    return (size >= 0 ? ULONG_MAX : starting_bit);
+
+  limb = *p;
+
+  if (size >= 0)
+    {
+      /* Mask to 0 all bits before starting_bit, thus ignoring them. */
+      limb &= (MP_LIMB_T_MAX << (starting_bit % GMP_NUMB_BITS));
+
+      if (limb == 0)
+        {
+          /* If it's the high limb which is zero after masking, then there's
+             no 1 bits after starting_bit.  */
+          p++;
+          if (p == u_end)
+            return ULONG_MAX;
+
+          /* Otherwise search further for a non-zero limb.  The high limb is
+             non-zero, if nothing else.  */
+          for (;;)
+            {
+              limb = *p;
+              if (limb != 0)
+                break;
+              p++;
+              ASSERT (p < u_end);
+            }
+        }
+    }
+  else
+    {
+      mp_srcptr  q;
+
+      /* If there's a non-zero limb before ours then we're in the ones
+         complement region.  Search from *(p-1) downwards since that might
+         give better cache locality, and since a non-zero in the middle of a
+         number is perhaps a touch more likely than at the end.  */
+      q = p;
+      while (q != u_ptr)
+        {
+          q--;
+          if (*q != 0)
+            goto inverted;
+        }
+
+      if (limb == 0)
+        {
+          /* Skip zero limbs, to find the start of twos complement.  The
+             high limb is non-zero, if nothing else.  This search is
+             necessary so the -limb is applied at the right spot. */
+          do
+            {
+              p++;
+              ASSERT (p < u_end);
+              limb = *p;
+            }
+          while (limb == 0);
+
+          /* Apply twos complement, and look for a 1 bit in that.  Since
+             limb!=0 here, also have (-limb)!=0 so there's certainly a 1
+             bit.  */
+          limb = -limb;
+          goto got_limb;
+        }
+
+      /* Adjust so ~limb implied by searching for 0 bit becomes -limb.  */
+      limb--;
+
+    inverted:
+      /* Now seeking a 0 bit. */
+
+      /* Mask to 1 all bits before starting_bit, thus ignoring them. */
+      limb |= (CNST_LIMB(1) << (starting_bit % GMP_NUMB_BITS)) - 1;
+
+      /* Search for a limb which is not all ones.  If the end is reached
+         then the zero immediately past the end is the result.  */
+      while (limb == GMP_NUMB_MAX)
+        {
+          p++;
+          if (p == u_end)
+            return abs_size * GMP_NUMB_BITS;
+          limb = *p;
+        }
+
+      /* Now seeking low 1 bit. */
+      limb = ~limb;
+    }
+
+ got_limb:
+  /* Mask to 0 all bits above the lowest 1 bit. */
+  ASSERT (limb != 0);
+  limb &= -limb;
+
+  count_leading_zeros (cnt, limb);
+  return (p - u_ptr) * GMP_NUMB_BITS + GMP_LIMB_BITS - 1 - cnt;
 }