diff --git a/ase/awk/awk.h b/ase/awk/awk.h
index 2489414e..6b6397fa 100644
--- a/ase/awk/awk.h
+++ b/ase/awk/awk.h
@@ -1,5 +1,5 @@
 /* 
- * $Id: awk.h,v 1.158 2006-12-02 16:26:03 bacon Exp $
+ * $Id: awk.h,v 1.159 2006-12-04 06:04:05 bacon Exp $
  */
 
 #ifndef _ASE_AWK_AWK_H_
@@ -151,11 +151,11 @@ enum
 	/* support shift operators */
 	ASE_AWK_SHIFT       = (1 << 4), 
 
-	/* support comments by a hash sign */
-	ASE_AWK_HASHSIGN    = (1 << 5), 
+	/* enable the idiv operator (double slashes) */
+	ASE_AWK_IDIV        = (1 << 5), 
 
-	/* support comments by double slashes */
-	ASE_AWK_DBLSLASHES  = (1 << 6), 
+	/* support comments by a hash sign */
+	ASE_AWK_HASHSIGN    = (1 << 6), 
 
 	/* support string concatenation in tokenization.
 	 * this option can change the behavior of a certain construct.
diff --git a/ase/awk/jni.c b/ase/awk/jni.c
index 0bb8e441..f3210419 100644
--- a/ase/awk/jni.c
+++ b/ase/awk/jni.c
@@ -1,5 +1,5 @@
 /*
- * $Id: jni.c,v 1.35 2006-12-02 16:26:03 bacon Exp $
+ * $Id: jni.c,v 1.36 2006-12-04 06:04:06 bacon Exp $
  */
 
 #include <ase/awk/jni.h>
@@ -234,8 +234,8 @@ JNIEXPORT void JNICALL Java_ase_awk_Awk_open (JNIEnv* env, jobject obj)
 
 	(*env)->SetLongField (env, obj, fid_handle, (jlong)awk);
 
-	opt = ASE_AWK_EXPLICIT | ASE_AWK_UNIQUEAFN | ASE_AWK_DBLSLASHES |
-		ASE_AWK_SHADING | ASE_AWK_IMPLICIT | ASE_AWK_SHIFT | 
+	opt = ASE_AWK_EXPLICIT | ASE_AWK_UNIQUEAFN | ASE_AWK_SHADING |
+		ASE_AWK_IMPLICIT | ASE_AWK_SHIFT | ASE_AWK_IDIV |
 		ASE_AWK_EXTIO | ASE_AWK_BLOCKLESS | ASE_AWK_HASHSIGN | 
 		ASE_AWK_NEXTOFILE;
 	ase_awk_setopt (awk, opt);
diff --git a/ase/awk/parse.c b/ase/awk/parse.c
index d7209818..31787346 100644
--- a/ase/awk/parse.c
+++ b/ase/awk/parse.c
@@ -1,5 +1,5 @@
 /*
- * $Id: parse.c,v 1.214 2006-11-29 02:54:15 bacon Exp $
+ * $Id: parse.c,v 1.215 2006-12-04 06:04:06 bacon Exp $
  */
 
 #include <ase/awk/awk_i.h>
@@ -16,6 +16,7 @@ enum
 	TOKEN_MINUS_ASSIGN,
 	TOKEN_MUL_ASSIGN,
 	TOKEN_DIV_ASSIGN,
+	TOKEN_IDIV_ASSIGN,
 	TOKEN_MOD_ASSIGN,
 	TOKEN_EXP_ASSIGN,
 
@@ -33,6 +34,7 @@ enum
 	TOKEN_MINUSMINUS,
 	TOKEN_MUL,
 	TOKEN_DIV,
+	TOKEN_IDIV,
 	TOKEN_MOD,
 	TOKEN_LOR,
 	TOKEN_LAND,
@@ -1540,68 +1542,6 @@ static ase_awk_nde_t* __parse_binary_expr (
 			return ASE_NULL;
 		}
 
-#if 0
-		/* TODO: enhance constant folding. do it in a better way */
-		/* TODO: differentiate different types of numbers ... */
-		if (left->type == ASE_AWK_NDE_INT && 
-		    right->type == ASE_AWK_NDE_INT) 
-		{
-			ase_long_t l, r;
-
-			l = ((ase_awk_nde_int_t*)left)->val; 
-			r = ((ase_awk_nde_int_t*)right)->val; 
-
-			/* TODO: more operators */
-			if (opcode == ASE_AWK_BINOP_PLUS) l += r;
-			else if (opcode == ASE_AWK_BINOP_MINUS) l -= r;
-			else if (opcode == ASE_AWK_BINOP_MUL) l *= r;
-			else if (opcode == ASE_AWK_BINOP_DIV && r != 0) l /= r;
-			else if (opcode == ASE_AWK_BINOP_MOD && r != 0) l %= r;
-			else goto skip_constant_folding;
-
-			ase_awk_clrpt (awk, right);
-			((ase_awk_nde_int_t*)left)->val = l;
-
-			if (((ase_awk_nde_int_t*)left)->str != ASE_NULL)
-			{
-				ASE_AWK_FREE (awk, ((ase_awk_nde_int_t*)left)->str);
-				((ase_awk_nde_int_t*)left)->str = ASE_NULL;
-				((ase_awk_nde_int_t*)left)->len = 0;
-			}
-
-			continue;
-		} 
-		else if (left->type == ASE_AWK_NDE_REAL && 
-		         right->type == ASE_AWK_NDE_REAL) 
-		{
-			ase_real_t l, r;
-
-			l = ((ase_awk_nde_real_t*)left)->val; 
-			r = ((ase_awk_nde_real_t*)right)->val; 
-
-			/* TODO: more operators */
-			if (opcode == ASE_AWK_BINOP_PLUS) l += r;
-			else if (opcode == ASE_AWK_BINOP_MINUS) l -= r;
-			else if (opcode == ASE_AWK_BINOP_MUL) l *= r;
-			else if (opcode == ASE_AWK_BINOP_DIV) l /= r;
-			else goto skip_constant_folding;
-
-			ase_awk_clrpt (awk, right);
-			((ase_awk_nde_real_t*)left)->val = l;
-
-			if (((ase_awk_nde_real_t*)left)->str != ASE_NULL)
-			{
-				ASE_AWK_FREE (awk, ((ase_awk_nde_real_t*)left)->str);
-				((ase_awk_nde_real_t*)left)->str = ASE_NULL;
-				((ase_awk_nde_real_t*)left)->len = 0;
-			}
-
-			continue;
-		}
-		/* TODO: enhance constant folding more... */
-
-	skip_constant_folding:
-#endif
 		nde = (ase_awk_nde_exp_t*) ASE_AWK_MALLOC (
 			awk, ASE_SIZEOF(ase_awk_nde_exp_t));
 		if (nde == ASE_NULL) 
@@ -1962,9 +1902,10 @@ static ase_awk_nde_t* __parse_multiplicative (ase_awk_t* awk)
 {
 	static __binmap_t map[] = 
 	{
-		{ TOKEN_MUL, ASE_AWK_BINOP_MUL },
-		{ TOKEN_DIV, ASE_AWK_BINOP_DIV },
-		{ TOKEN_MOD, ASE_AWK_BINOP_MOD },
+		{ TOKEN_MUL,  ASE_AWK_BINOP_MUL },
+		{ TOKEN_DIV,  ASE_AWK_BINOP_DIV },
+		{ TOKEN_IDIV, ASE_AWK_BINOP_IDIV },
+		{ TOKEN_MOD,  ASE_AWK_BINOP_MOD },
 		/* { TOKEN_EXP, ASE_AWK_BINOP_EXP }, */
 		{ TOKEN_EOF, 0 }
 	};
@@ -3781,11 +3722,46 @@ static int __get_token (ase_awk_t* awk)
 			ADD_TOKEN_CHAR (awk, c);
 			GET_CHAR (awk);
 		}
+		else if ((awk->option & ASE_AWK_IDIV) && c == ASE_T('/'))
+		{
+			ADD_TOKEN_CHAR (awk, c);
+			GET_CHAR_TO (awk, c);
+			if (c == ASE_T('='))
+			{
+				SET_TOKEN_TYPE (awk, TOKEN_IDIV_ASSIGN);
+				ADD_TOKEN_CHAR (awk, c);
+				GET_CHAR (awk);
+			}
+			else 
+			{
+				SET_TOKEN_TYPE (awk, TOKEN_IDIV);
+			}
+		}
 		else
 		{
 			SET_TOKEN_TYPE (awk, TOKEN_DIV);
 		}
 	}
+#if 0 
+	/* TODO: is it a good idea to use a back-slash for 
+	 *       the idiv operator like BASIC? */
+	else if ((awk->option & ASE_AWK_IDIV) && c == ASE_T('\\'))
+	{
+		ADD_TOKEN_CHAR (awk, c);
+		GET_CHAR_TO (awk, c);
+
+		if (c == ASE_T('='))
+		{
+			SET_TOKEN_TYPE (awk, TOKEN_IDIV_ASSIGN);
+			ADD_TOKEN_CHAR (awk, c);
+			GET_CHAR (awk);
+		}
+		else
+		{
+			SET_TOKEN_TYPE (awk, TOKEN_IDIV);
+		}
+	}
+#endif
 	else if (c == ASE_T('%')) 
 	{
 		ADD_TOKEN_CHAR (awk, c);
@@ -4254,6 +4230,7 @@ static int __skip_comment (ase_awk_t* awk)
 	if (c != ASE_T('/')) return 0; /* not a comment */
 	GET_CHAR_TO (awk, c);
 
+#if 0
 	if ((awk->option & ASE_AWK_DBLSLASHES) && c == ASE_T('/')) 
 	{
 		do 
@@ -4265,7 +4242,9 @@ static int __skip_comment (ase_awk_t* awk)
 		GET_CHAR (awk);
 		return 1; /* comment by // */
 	}
-	else if (c == ASE_T('*')) 
+	else
+#endif
+	if (c == ASE_T('*')) 
 	{
 		do 
 		{
@@ -4332,6 +4311,7 @@ static int __assign_to_opcode (ase_awk_t* awk)
 		ASE_AWK_ASSOP_MINUS,
 		ASE_AWK_ASSOP_MUL,
 		ASE_AWK_ASSOP_DIV,
+		ASE_AWK_ASSOP_IDIV,
 		ASE_AWK_ASSOP_MOD,
 		ASE_AWK_ASSOP_EXP
 	};
diff --git a/ase/awk/run.c b/ase/awk/run.c
index 7e358c22..fa2e238f 100644
--- a/ase/awk/run.c
+++ b/ase/awk/run.c
@@ -1,5 +1,5 @@
 /*
- * $Id: run.c,v 1.289 2006-12-03 15:05:01 bacon Exp $
+ * $Id: run.c,v 1.290 2006-12-04 06:04:07 bacon Exp $
  */
 
 #include <ase/awk/awk_i.h>
@@ -141,6 +141,8 @@ static ase_awk_val_t* __eval_binop_mul (
 	ase_awk_run_t* run, ase_awk_val_t* left, ase_awk_val_t* right);
 static ase_awk_val_t* __eval_binop_div (
 	ase_awk_run_t* run, ase_awk_val_t* left, ase_awk_val_t* right);
+static ase_awk_val_t* __eval_binop_idiv (
+	ase_awk_run_t* run, ase_awk_val_t* left, ase_awk_val_t* right);
 static ase_awk_val_t* __eval_binop_mod (
 	ase_awk_run_t* run, ase_awk_val_t* left, ase_awk_val_t* right);
 static ase_awk_val_t* __eval_binop_exp (
@@ -2719,6 +2721,10 @@ static ase_awk_val_t* __eval_assignment (ase_awk_run_t* run, ase_awk_nde_t* nde)
 		{
 			tmp = __eval_binop_div (run, val2, val);
 		}
+		else if (ass->opcode == ASE_AWK_ASSOP_IDIV)
+		{
+			tmp = __eval_binop_idiv (run, val2, val);
+		}
 		else if (ass->opcode == ASE_AWK_ASSOP_MOD)
 		{
 			tmp = __eval_binop_mod (run, val2, val);
@@ -3029,6 +3035,7 @@ static ase_awk_val_t* __eval_binary (ase_awk_run_t* run, ase_awk_nde_t* nde)
 		__eval_binop_minus,
 		__eval_binop_mul,
 		__eval_binop_div,
+		__eval_binop_idiv,
 		__eval_binop_mod,
 		__eval_binop_exp,
 
@@ -3808,16 +3815,61 @@ static ase_awk_val_t* __eval_binop_div (
 	}
 	else if (n3 == 1)
 	{
-		res = ase_awk_makerealval (run, (ase_real_t)r1 / (ase_real_t)l2);
+		res = ase_awk_makerealval (
+			run, (ase_real_t)r1 / (ase_real_t)l2);
 	}
 	else if (n3 == 2)
 	{
-		res = ase_awk_makerealval (run, (ase_real_t)l1 / (ase_real_t)r2);
+		res = ase_awk_makerealval (
+			run, (ase_real_t)l1 / (ase_real_t)r2);
 	}
 	else
 	{
 		ASE_AWK_ASSERT (run->awk, n3 == 3);
-		res = ase_awk_makerealval (run, (ase_real_t)r1 / (ase_real_t)r2);
+		res = ase_awk_makerealval (
+			run, (ase_real_t)r1 / (ase_real_t)r2);
+	}
+
+	if (res == ASE_NULL) PANIC (run, ASE_AWK_ENOMEM);
+	return res;
+}
+
+static ase_awk_val_t* __eval_binop_idiv (
+	ase_awk_run_t* run, ase_awk_val_t* left, ase_awk_val_t* right)
+{
+	int n1, n2, n3;
+	ase_long_t l1, l2;
+	ase_real_t r1, r2, quo;
+	ase_awk_val_t* res;
+
+	n1 = ase_awk_valtonum (run, left, &l1, &r1);
+	n2 = ase_awk_valtonum (run, right, &l2, &r2);
+
+	if (n1 == -1 || n2 == -1) PANIC (run, ASE_AWK_EOPERAND);
+
+	n3 = n1 + (n2 << 1);
+	if (n3 == 0)
+	{
+		if (l2 == 0) PANIC (run, ASE_AWK_EDIVBYZERO);
+		res = ase_awk_makeintval (
+			run, (ase_long_t)l1 / (ase_long_t)l2);
+	}
+	else if (n3 == 1)
+	{
+		quo = (ase_real_t)r1 / (ase_real_t)l2;
+		res = ase_awk_makeintval (run, (ase_long_t)quo);
+	}
+	else if (n3 == 2)
+	{
+		quo = (ase_real_t)l1 / (ase_real_t)r2;
+		res = ase_awk_makeintval (run, (ase_long_t)quo);
+	}
+	else
+	{
+		ASE_AWK_ASSERT (run->awk, n3 == 3);
+
+		quo = (ase_real_t)r1 / (ase_real_t)r2;
+		res = ase_awk_makeintval (run, (ase_long_t)quo);
 	}
 
 	if (res == ASE_NULL) PANIC (run, ASE_AWK_ENOMEM);
@@ -3841,7 +3893,8 @@ static ase_awk_val_t* __eval_binop_mod (
 	if (n3 == 0)
 	{
 		if  (l2 == 0) PANIC (run, ASE_AWK_EDIVBYZERO);
-		res = ase_awk_makeintval (run, (ase_long_t)l1 % (ase_long_t)l2);
+		res = ase_awk_makeintval (
+			run, (ase_long_t)l1 % (ase_long_t)l2);
 	}
 	else PANIC (run, ASE_AWK_EOPERAND);
 
diff --git a/ase/awk/run.h b/ase/awk/run.h
index 9e67785e..79d19fb5 100644
--- a/ase/awk/run.h
+++ b/ase/awk/run.h
@@ -1,5 +1,5 @@
 /*
- * $Id: run.h,v 1.28 2006-11-24 13:20:49 bacon Exp $
+ * $Id: run.h,v 1.29 2006-12-04 06:04:07 bacon Exp $
  */
 
 #ifndef _ASE_AWK_RUN_H_
@@ -17,6 +17,7 @@ enum ase_awk_assop_type_t
 	ASE_AWK_ASSOP_MINUS, /* -= */
 	ASE_AWK_ASSOP_MUL,   /* *= */
 	ASE_AWK_ASSOP_DIV,   /* /= */
+	ASE_AWK_ASSOP_IDIV,  /* //= */
 	ASE_AWK_ASSOP_MOD,   /* %= */
 	ASE_AWK_ASSOP_EXP    /* **= */
 };
@@ -47,6 +48,7 @@ enum  ase_awk_binop_type_t
 	ASE_AWK_BINOP_MINUS,
 	ASE_AWK_BINOP_MUL,
 	ASE_AWK_BINOP_DIV,
+	ASE_AWK_BINOP_IDIV,
 	ASE_AWK_BINOP_MOD,
 	ASE_AWK_BINOP_EXP,
 
diff --git a/ase/awk/tree.c b/ase/awk/tree.c
index 9fc6138b..b3c16565 100644
--- a/ase/awk/tree.c
+++ b/ase/awk/tree.c
@@ -1,5 +1,5 @@
 /*
- * $Id: tree.c,v 1.92 2006-11-29 02:54:16 bacon Exp $
+ * $Id: tree.c,v 1.93 2006-12-04 06:04:07 bacon Exp $
  */
 
 #include <ase/awk/awk_i.h>
@@ -11,6 +11,7 @@ static const ase_char_t* __assop_str[] =
 	ASE_T("-="),
 	ASE_T("*="),
 	ASE_T("/="),
+	ASE_T("//="),
 	ASE_T("%="),
 	ASE_T("**=")
 };
diff --git a/ase/test/awk/awk.c b/ase/test/awk/awk.c
index 1aea6040..eca9bfb3 100644
--- a/ase/test/awk/awk.c
+++ b/ase/test/awk/awk.c
@@ -1,5 +1,5 @@
 /*
- * $Id: awk.c,v 1.133 2006-11-30 10:40:40 bacon Exp $
+ * $Id: awk.c,v 1.134 2006-12-04 06:04:07 bacon Exp $
  */
 
 #include <ase/awk/awk.h>
@@ -755,7 +755,7 @@ static int __main (int argc, ase_char_t* argv[])
 	      ASE_AWK_EXPLICIT | 
 	      ASE_AWK_UNIQUEAFN | 
 	      ASE_AWK_HASHSIGN | 
-	      /*ASE_AWK_DBLSLASHES |*/ 
+	      ASE_AWK_IDIV |
 	      ASE_AWK_SHADING | 
 	      ASE_AWK_SHIFT | 
 	      ASE_AWK_EXTIO |