diff --git a/C/agc.c b/C/agc.c
index 189392a9c..5aca4bd4c 100644
--- a/C/agc.c
+++ b/C/agc.c
@@ -22,6 +22,7 @@ static char     SccsId[] = "@(#)agc.c	1.3 3/15/90";
 #include "absmi.h"
 #include "alloc.h"
 #include "yapio.h"
+#include "attvar.h"
 
 #ifdef DEBUG
 /* #define DEBUG_RESTORE2 1 */
@@ -188,9 +189,6 @@ mark_atoms(void)
   do {
 #ifdef DEBUG_RESTORE2		/* useful during debug */
     fprintf(errout, "Restoring %s\n", at->StrOfAE);
-    if (strcmp(at->StrOfAE,"$module_expansion") == 0) {
-      printf("oops\n");
-    }
 #endif
     RestoreEntries(RepProp(at->PropsOfAE));
     atm = at->NextOfAE;
@@ -235,55 +233,60 @@ mark_local(void)
   }
 }
 
+static CELL *
+mark_global_cell(CELL *pt)
+{   
+  CELL reg = *pt;
+
+  if (IsVarTerm(reg)) {
+    /* skip bitmaps */
+    switch(reg) {
+    case (CELL)FunctorDouble:
+#if SIZEOF_DOUBLE == 2*SIZEOF_LONG_INT
+      return pt + 4;
+#else
+      return pt + 3;
+#endif
+#if USE_GMP
+    case (CELL)FunctorBigInt:
+      {
+	Int sz = 1+
+	  sizeof(MP_INT)+
+	  (((MP_INT *)(pt+1))->_mp_alloc*sizeof(mp_limb_t));
+	return pt + sz+1;
+      }
+#endif
+    case (CELL)FunctorLongInt:
+      return pt += 3;
+      break;
+    }
+  } else if (IsAtomTerm(reg)) {
+    MarkAtomEntry(RepAtom(AtomOfTerm(reg)));
+    return pt+1;
+  }
+  return pt+1;
+}
+
 static void
 mark_global(void)
 {
-  register CELL *pt;
+  CELL *pt;
 
   /*
    * to clean the global now that functors are just variables pointing to
    * the code 
    */
-  pt = CellPtr(Yap_GlobalBase);
+#if COROUTINING
+  CELL *ptf = (CELL *)DelayTop();
+
+  pt = (CELL *)Yap_GlobalBase;
+  while (pt < ptf) {
+    pt = mark_global_cell(pt);
+  }
+#endif
+  pt = H0;
   while (pt < H) {
-    register CELL reg;
-    
-    reg = *pt;
-    if (IsVarTerm(reg)) {
-      pt++;
-      continue;
-    } else if (IsAtomTerm(reg)) {
-      	MarkAtomEntry(RepAtom(AtomOfTerm(reg)));
-    } else if (IsApplTerm(reg)) {
-      Functor f = FunctorOfTerm(reg);
-      if (f <= FunctorDouble && f >= FunctorLongInt) {
-	/* skip bitmaps */
-	switch((CELL)f) {
-	case (CELL)FunctorDouble:
-#if SIZEOF_DOUBLE == 2*SIZEOF_LONG_INT
-	  pt += 3;
-#else
-	  pt += 2;
-#endif
-	  break;
-#if USE_GMP
-	case (CELL)FunctorBigInt:
-	  {
-	    Int sz = 1+
-	      sizeof(MP_INT)+
-	      (((MP_INT *)(pt+1))->_mp_alloc*sizeof(mp_limb_t));
-	    pt += sz;
-	  }
-	  break;
-#endif
-	case (CELL)FunctorLongInt:
-	default:
-	  pt += 2;
-	  break;
-	}
-      }
-    }
-    pt++;
+    pt = mark_global_cell(pt);
   }
 }
 
diff --git a/C/index.c b/C/index.c
index 27066e57c..84e25be29 100644
--- a/C/index.c
+++ b/C/index.c
@@ -11,8 +11,11 @@
 * File:		index.c							 *
 * comments:	Indexing a Prolog predicate				 *
 *									 *
-* Last rev:     $Date: 2005-05-25 18:58:37 $,$Author: vsc $						 *
+* Last rev:     $Date: 2005-05-27 21:44:00 $,$Author: vsc $						 *
 * $Log: not supported by cvs2svn $
+* Revision 1.126  2005/05/25 18:58:37  vsc
+* fix another bug in nth_instance, thanks to Pat Caldon
+*
 * Revision 1.125  2005/04/28 14:50:45  vsc
 * clause should always deref before testing type
 *
@@ -6104,6 +6107,11 @@ clean_up_index(LogUpdIndex *blk, yamop **jlbl, PredEntry *ap)
   }
 }
 
+static int is_trust(OPCODE opc) {
+  op_numbers op = Yap_op_from_opcode(opc);
+  return op == _trust;
+}
+
 static yamop *
 insertz_in_lu_block(LogUpdIndex *blk, PredEntry *ap, yamop *code)
 {
@@ -6117,7 +6125,10 @@ insertz_in_lu_block(LogUpdIndex *blk, PredEntry *ap, yamop *code)
     begin = NEXTOP(begin, xll);
     op = Yap_op_from_opcode(begin->opc);
   }
-  if (op != _enter_lu_pred && op != _stale_lu_index) {
+  /* block should start with an enter_lu_pred and end with a trust,
+     otherwise I just don't understand what is going on */
+  if ((op != _enter_lu_pred && op != _stale_lu_index) ||
+      ! is_trust(begin->u.xll.l2->opc)) {
     if (blk->ClFlags & SwitchRootMask) {
       Yap_kill_iblock((ClauseUnion *)blk, NULL, ap);
     } else {
@@ -6166,6 +6177,7 @@ insertz_in_lu_block(LogUpdIndex *blk, PredEntry *ap, yamop *code)
 	if (ap->ArityOfPE >= 2 && 
 	    ap->ArityOfPE <= 4) {
 	  yamop *cl = last->u.ld.d;
+
 	  nlast->opc = Yap_opcode(_retry2+(ap->ArityOfPE-2));
 	  nlast->u.l.l = cl;
 	  where = NEXTOP(nlast,l);