diff --git a/H/absmi.h b/H/absmi.h
index e33a7f3c5..f7d093366 100644
--- a/H/absmi.h
+++ b/H/absmi.h
@@ -690,9 +690,7 @@ Macros to check the limits of stacks
 
 #if (defined(SBA) && defined(YAPOR)) || defined(TABLING)
 #define check_stack(Label, GLOB)                             \
- if ( (Int)(Unsigned(E_YREG) - CFREG) < (Int)(GLOB) &&       \
-       (choiceptr)E_YREG < B_FZ && E_YREG > H_FZ       &&       \
-       (GLOB) > H_FZ && (GLOB) < (CELL *)B_FZ) goto Label
+ if ( (Int)(Unsigned(YOUNGEST_CP((choiceptr)E_YREG,B_FZ)) - Unsigned(YOUNGEST_H(H_FZ,GLOB))) < CFREG  ) goto Label
 #else
 #define check_stack(Label, GLOB)                             \
  if ( (Int)(Unsigned(E_YREG) - Unsigned(GLOB)) < CFREG ) goto Label
diff --git a/H/amidefs.h b/H/amidefs.h
index 1f3180b3f..829729511 100644
--- a/H/amidefs.h
+++ b/H/amidefs.h
@@ -11,8 +11,11 @@
 * File:		amidefs.h						 *
 * comments:	Abstract machine peculiarities				 *
 *									 *
-* Last rev:     $Date: 2005-04-10 04:01:13 $							 *
+* Last rev:     $Date: 2005-05-30 06:07:35 $							 *
 * $Log: not supported by cvs2svn $
+* Revision 1.27  2005/04/10 04:01:13  vsc
+* bug fixes, I hope!
+*
 * Revision 1.26  2004/09/30 21:37:41  vsc
 * fixes for thread support
 *
@@ -649,11 +652,24 @@ typedef struct choicept {
         :                                                                                     \
           (SHARED_CP(CP2) ? TRUE : CP1 <= CP2)                                                   \
         )
+
+#define YOUNGER_H(H1, H2) FIXMEE!!!!
+
+
 #else /* ENV_COPY || ACOW */
 #define YOUNGER_CP(CP1, CP2)           ((CP1) <  (CP2))
 #define EQUAL_OR_YOUNGER_CP(CP1, CP2)  ((CP1) <= (CP2))
+
+#define YOUNGER_H(H1, H2)           ((CELL *)(H1) > (CELL *)(H2))
+
 #endif /* SBA */
 
+#define YOUNGEST_CP(CP1, CP2)           (YOUNGER_CP(CP1,CP2) ? (CP1) : (CP2))
+
+#define YOUNGEST_H(H1, H2)           (YOUNGER_H(H1,H2) ? (CELL *)(H1) : (CELL *)(H2))
+
+
+
 /*
    Environment Structure (CP, E, and CUT_B). Yap always saves the B
    where to cut to, even if not needed.
diff --git a/OPTYap/tab.macros.h b/OPTYap/tab.macros.h
index 8c2c8c27d..74be1dc56 100644
--- a/OPTYap/tab.macros.h
+++ b/OPTYap/tab.macros.h
@@ -53,13 +53,13 @@ STD_PROTO(static inline tg_sol_fr_ptr CUT_prune_tg_solution_frames, (tg_sol_fr_p
 #define	TabPairTagBits         MKTAG(0x5,3)
 #define	TabApplTagBits         MKTAG(0x5,0)
 #else
-#define	TabTagBits             OOOOPPS!!! Inconsistent Tabling Tag Scheme
-#define TabNumberOfLowTagBits  OOOOPPS!!! Inconsistent Tabling Tag Scheme
-#define	TabVarTagBits          OOOOPPS!!! Inconsistent Tabling Tag Scheme
-#define	TabAtomTagBits         OOOOPPS!!! Inconsistent Tabling Tag Scheme
-#define	TabNumberTagBits       OOOOPPS!!! Inconsistent Tabling Tag Scheme
-#define	TabPairTagBits         OOOOPPS!!! Inconsistent Tabling Tag Scheme
-#define	TabApplTagBits         OOOOPPS!!! Inconsistent Tabling Tag Scheme
+#define	TabTagBits             MKTAG(0x0,LowTagBits)
+#define TabNumberOfLowTagBits  LowTagBits
+#define	TabVarTagBits          MKTAG(0x0,0)
+#define	TabAtomTagBits         AtomTag
+#define	TabNumberTagBits       NumberTag
+#define	TabPairTagBits         PairBits
+#define	TabApplTagBits         ApplBit
 #endif /* TAGS_FAST_OPS */