diff --git a/C/absmi.c b/C/absmi.c
index 392e5bee3..b791cf3c6 100755
--- a/C/absmi.c
+++ b/C/absmi.c
@@ -968,7 +968,7 @@ Yap_absmi(int inp)
       {
 	yamop *pt;
 	saveregs();
-	pt = Yap_ExoLookup(PredFromDefCode(PREG));
+	pt = Yap_ExoLookup(PredFromDefCode(PREG) PASS_REGS);
 	setregs();
 #ifdef SHADOW_S
 	SREG = S;
@@ -1050,12 +1050,13 @@ Yap_absmi(int inp)
       Op(retry_exo, lp);
       BEGD(d0);
       CACHE_Y(B);
-      saveregs();
-      d0 = Yap_NextExo(B_YREG, (struct index_t *)PREG->u.lp.l);
-      setregs();
-#ifdef SHADOW_S
-      SREG = S;
-#endif
+      {
+	struct index_t *it = (struct index_t *)(PREG->u.lp.l);
+	CELL offset = EXO_ADDRESS_TO_OFFSET(it,(CELL *)((CELL *)(B+1))[it->arity]);
+	d0 = it->links[offset];
+	((CELL *)(B+1))[it->arity] = (CELL)EXO_OFFSET_TO_ADDRESS(it, d0);
+	SREG = it->cls+it->arity*offset;
+      }
       if (d0) {
 	/* After retry, cut should be pointing at the parent
 	 * choicepoint for the current B */
diff --git a/C/exo.c b/C/exo.c
index e827e1f16..68543ce85 100644
--- a/C/exo.c
+++ b/C/exo.c
@@ -58,12 +58,12 @@ HASH(UInt hash0, UInt j, CELL *cl, struct index_t *it)
 
 /* search for matching elements */
 static int 
-MATCH(CELL *clp, CELL *kvp, UInt j, struct index_t *it)
+MATCH(CELL *clp, CELL *kvp, UInt j, struct index_t *it, UInt bnds[])
 {
   if ((kvp - it->cls)%it->arity != j)
     return FALSE;
   do {
-    if ( LOCAL_ibnds[j] && *clp != *kvp)
+    if ( bnds[j] && *clp != *kvp)
       return FALSE;
     clp--;
     kvp--;
@@ -112,14 +112,14 @@ ADD_TO_TRY_CHAIN(CELL *kvp, CELL *cl, struct index_t *it)
  * else
  */
 static void
-INSERT(CELL *cl, struct index_t *it, UInt arity, UInt base, UInt hash0)
+INSERT(CELL *cl, struct index_t *it, UInt arity, UInt base, UInt hash0, UInt bnds[])
 {
   UInt j = base;
   CELL *kvp;
   UInt hash;
 
   /* skip over argument */
-  while (!LOCAL_ibnds[j]) {
+  while (!bnds[j]) {
     j++;
   }
   /* j is the firs bound element */
@@ -134,16 +134,16 @@ INSERT(CELL *cl, struct index_t *it, UInt arity, UInt base, UInt hash0)
     it->nentries++;
     it->key[hash] = cl+j;
     return;
-  } else if (MATCH(cl+j, kvp, j, it))  {
+  } else if (MATCH(cl+j, kvp, j, it, bnds))  {
     /* collision */
     UInt k;
     CELL *target;
     
     for (k =j+1, target = kvp+1; k < arity; k++,target++ ) {
-      if (LOCAL_ibnds[k]) {
+      if (bnds[k]) {
 	if (*target != cl[k]) {
 	  /* found a new forking point */
-	  INSERT(cl, it, arity, k, hash0);
+	  INSERT(cl, it, arity, k, hash0, bnds);
 	  return;
 	}
       }
@@ -160,8 +160,9 @@ INSERT(CELL *cl, struct index_t *it, UInt arity, UInt base, UInt hash0)
 }
 
 static yamop *
-LOOKUP(struct index_t *it, UInt arity, UInt j)
+LOOKUP(struct index_t *it, UInt arity, UInt j, UInt bnds[])
 {
+  CACHE_REGS
   CELL *kvp;
   UInt hash, hash0 = 0;
 
@@ -175,13 +176,13 @@ LOOKUP(struct index_t *it, UInt arity, UInt j)
   if (kvp == NULL) {
     /* simple case, no element */
     return FAILCODE;
-  } else if (MATCH(XREGS+(j+1), kvp, j, it))  {
+  } else if (MATCH(XREGS+(j+1), kvp, j, it, bnds))  {
     /* found element */
     UInt k;
     CELL *target;
 
     for (k =j+1, target = kvp+1; k < arity; k++ ) {
-      if (LOCAL_ibnds[k]) {
+      if (bnds[k]) {
 	if (*target != XREGS[k+1]) {
 	  j = k;
 	  goto hash;
@@ -202,14 +203,14 @@ LOOKUP(struct index_t *it, UInt arity, UInt j)
 }
 
 static void
-fill_hash(UInt bmap, struct index_t *it)
+fill_hash(UInt bmap, struct index_t *it, UInt bnds[])
 {
   UInt i;
   UInt arity = it->arity;
   CELL *cl = it->cls;
 
   for (i=0; i < it->nels; i++) {
-    INSERT(cl, it, arity, 0, 0);
+    INSERT(cl, it, arity, 0, 0, bnds);
     cl += arity;
   }
   for (i=0; i < it->hsize; i++) {
@@ -226,7 +227,7 @@ fill_hash(UInt bmap, struct index_t *it)
 }
 
 static struct index_t *
-add_index(struct index_t **ip, UInt bmap, PredEntry *ap, UInt count)
+add_index(struct index_t **ip, UInt bmap, PredEntry *ap, UInt count, UInt bnds[])
 {
   UInt ncls = ap->cs.p_code.NOfClauses, j;
   CELL *base = NULL;
@@ -269,7 +270,7 @@ add_index(struct index_t **ip, UInt bmap, PredEntry *ap, UInt count)
   i->cls = (CELL *)((ADDR)ap->cs.p_code.FirstClause+2*sizeof(struct index_t *)); 
   *ip = i;
   if (count) {
-    fill_hash(bmap, i);
+    fill_hash(bmap, i, bnds);
     printf("entries=%ld collisions=%ld trys=%ld\n", i->nentries, i->ncollisions, i->ntrys);
     if (!i->ntrys) {
       i->is_key = TRUE;
@@ -311,7 +312,7 @@ add_index(struct index_t **ip, UInt bmap, PredEntry *ap, UInt count)
 }
 
 yamop  *
-Yap_ExoLookup(PredEntry *ap) 
+Yap_ExoLookup(PredEntry *ap USES_REGS) 
 {
   UInt arity = ap->ArityOfPE;
   UInt bmap = 0L, bit = 1, count = 0, j, j0 = 0;
@@ -345,10 +346,10 @@ Yap_ExoLookup(PredEntry *ap)
     i = i->next;
   }
   if (!i) {
-    i = add_index(ip, bmap, ap, count);
+    i = add_index(ip, bmap, ap, count, LOCAL_ibnds);
   }
   if (count)
-    return LOOKUP(i, arity, j0);
+    return LOOKUP(i, arity, j0, LOCAL_ibnds);
   else
     return i->code;
 }
@@ -356,6 +357,7 @@ Yap_ExoLookup(PredEntry *ap)
 CELL
 Yap_NextExo(choiceptr cptr, struct index_t *it) 
 {
+  CACHE_REGS
   CELL offset = EXO_ADDRESS_TO_OFFSET(it,(CELL *)((CELL *)(B+1))[it->arity]);
   CELL next = it->links[offset];
   ((CELL *)(B+1))[it->arity] = (CELL)EXO_OFFSET_TO_ADDRESS(it, next);
diff --git a/H/clause.h b/H/clause.h
index 65662ddc6..53362ad29 100644
--- a/H/clause.h
+++ b/H/clause.h
@@ -263,7 +263,7 @@ LogUpdClause  *STD_PROTO(Yap_NthClause,(PredEntry *,Int));
 LogUpdClause  *STD_PROTO(Yap_FollowIndexingCode,(PredEntry *,yamop *, Term *, yamop *,yamop *));
 
 /* exo.c */
-yamop    *Yap_ExoLookup(PredEntry *ap);
+yamop    *Yap_ExoLookup(PredEntry *ap USES_REGS);
 CELL    Yap_NextExo(choiceptr cpt, struct index_t *it);
 
 #if USE_THREADED_CODE