diff --git a/README.md b/README.md
index 9973779a..b6f955ce 100644
--- a/README.md
+++ b/README.md
@@ -5446,6 +5446,11 @@ x and y shall be within [0..M\_MAX\_NB\_ARGUMENT].
 Return 1 if x == y, 0 otherwise (resolution is performed at preprocessing time).
 x and y shall be within [0..M\_MAX\_NB\_ARGUMENT].
 
+##### M\_LESS\_THAN\_P(x, y)
+
+Return 1 if x < y, 0 otherwise (resolution is performed at preprocessing time).
+x and y shall be within [0..M\_MAX\_NB\_ARGUMENT].x
+
 ##### M\_COMMA\_P(arglist)
 
 Return 1 if there is a comma inside the argument list, 0 otherwise.
diff --git a/m-core.h b/m-core.h
index ecca701b..f97700bf 100644
--- a/m-core.h
+++ b/m-core.h
@@ -443,14 +443,17 @@ M_BEGIN_PROTECTED_CODE
 #define M_INC_50 51
 #define M_INC_51 52
 #define M_INC_52 53
-#define M_INC_53 M_INC_overflow_detected
+#define M_INC_53 OVERFLOW
+#define M_INC_OVERFLOW OVERFLOW
+
 
 /* Decrement the number given in argument (from [0..52[) 
    Generated by:
    for i in $(seq 1 52) ; do printf "#define M_DEC_%d %d\n" $i $(($i - 1)) ; done
 */
 #define M_DEC(x)          M_C(M_DEC_, x)
-#define M_DEC_0 M_DEC_underflow_detected
+#define M_DEC_UNDERFLOW UNDERFLOW
+#define M_DEC_0 UNDERFLOW
 #define M_DEC_1 0
 #define M_DEC_2 1
 #define M_DEC_3 2
@@ -1100,6 +1103,8 @@ M_BEGIN_PROTECTED_CODE
 #define M_PATTERN_TYPE_TYPE ,
 #define M_PATTERN_SUBTYPE_SUBTYPE ,
 #define M_PATTERN_IT_TYPE_IT_TYPE ,
+#define M_PATTERN_UNDERFLOW_UNDERFLOW ,
+#define M_PATTERN_OVERFLOW_OVERFLOW ,
 
 
 /* Necessary macros to handle recursivity,
@@ -1732,6 +1737,10 @@ M_BEGIN_PROTECTED_CODE
  */
 #define M_EQUAL(x,y) M_INV(M_NOTEQUAL(x,y))
 
+/* Return 1 if a < b, 0 otherwise 
+   a and b shall be in [0..M_MAX_NB_ARGUMENT] */
+#define M_LESS_THAN_P(a, b) M_KEYWORD_P(UNDERFLOW, M_SUB(a, b))
+
 /* Revert the list given as parameter
    Example: M_REVERSE(a,b,c) --> (c,b,a)  */
 /* Generated by:
diff --git a/tests/test-mcore.c b/tests/test-mcore.c
index a82d2c7a..13847307 100644
--- a/tests/test-mcore.c
+++ b/tests/test-mcore.c
@@ -112,6 +112,29 @@ static void test_incdec(void)
 
   assert( M_ADD(2,5) == M_SUB(10,3));
   assert( M_ADD(5,15) == M_SUB(25,5));
+
+  assert(M_EQUAL(2, 2));
+  assert(!M_EQUAL(1, 2));
+  assert(M_EQUAL(52, 52));
+
+  assert(!M_NOTEQUAL(2, 2));
+  assert(M_NOTEQUAL(1, 2));
+  assert(!M_NOTEQUAL(52, 52));
+
+  assert(!M_LESS_THAN_P(4, 2));
+  assert(!M_LESS_THAN_P(4, 3));
+  assert(!M_LESS_THAN_P(4, 4));
+  assert(M_LESS_THAN_P(4, 5));
+  assert(M_LESS_THAN_P(4, 6));
+  assert(M_LESS_THAN_P(4, 7));
+
+  assert(!M_KEYWORD_P(UNDERFLOW, M_SUB(1, 1)));
+  assert(M_KEYWORD_P(UNDERFLOW, M_SUB(1, 2)));
+  assert(M_KEYWORD_P(UNDERFLOW, M_SUB(1, 6)));
+  assert(M_KEYWORD_P(UNDERFLOW, M_SUB(1, 5)));
+  assert(!M_KEYWORD_P(OVERFLOW, M_ADD(M_MAX_NB_ARGUMENT, 1)));
+  assert(M_KEYWORD_P(OVERFLOW, M_ADD(M_MAX_NB_ARGUMENT, 2)));
+  assert(M_KEYWORD_P(OVERFLOW, M_ADD(M_MAX_NB_ARGUMENT, 3)));
 }
 
 static void test_return(void)