diff --git a/lib/comp.c b/lib/comp.c
index d32fd02..4d6efd6 100644
--- a/lib/comp.c
+++ b/lib/comp.c
@@ -1619,7 +1619,7 @@ static int collect_local_vardcl (hcl_t* hcl, hcl_cnode_t* obj, hcl_cnode_t** nex
 static int compile_lambda (hcl_t* hcl, hcl_cnode_t* src, int defun)
 {
 	hcl_cnode_t* cmd, * obj, * args;
-	hcl_oow_t nargs, ntmprs;
+	hcl_oow_t nargs, nlvars, tmpr_mask;
 	hcl_ooi_t jump_inst_pos, lfbase_pos, lfsize_pos;
 	hcl_oow_t saved_tv_wcount, tv_dup_start;
 	hcl_cnode_t* defun_name;
@@ -1752,22 +1752,24 @@ static int compile_lambda (hcl_t* hcl, hcl_cnode_t* src, int defun)
 
 	obj = HCL_CNODE_CONS_CDR(obj);
 	tv_dup_start = hcl->c->tv.s.len;
-	if (collect_local_vardcl(hcl, obj, &obj, tv_dup_start, &ntmprs) <= -1) return -1;
-
-	ntmprs += nargs; /* ntmprs: number of temporary variables including arguments */
-	HCL_ASSERT (hcl, ntmprs == hcl->c->tv.wcount - saved_tv_wcount);
-	if (ntmprs > MAX_CODE_NBLKTMPRS)
+	if (collect_local_vardcl(hcl, obj, &obj, tv_dup_start, &nlvars) <= -1) return -1;
+	
+	if (nlvars > MAX_CODE_NBLKLVARS)
 	{
-		hcl_setsynerrbfmt (hcl, HCL_SYNERR_VARFLOOD, HCL_CNODE_GET_LOC(args), HCL_NULL, "too many(%zu) variables in %.*js", ntmprs, HCL_CNODE_GET_TOKLEN(cmd), HCL_CNODE_GET_TOKPTR(cmd)); 
+		hcl_setsynerrbfmt (hcl, HCL_SYNERR_VARFLOOD, HCL_CNODE_GET_LOC(args), HCL_NULL, "too many(%zu) variables in %.*js", nlvars, HCL_CNODE_GET_TOKLEN(cmd), HCL_CNODE_GET_TOKPTR(cmd)); 
 		return -1;
 	}
 
+	HCL_ASSERT (hcl, nargs + nlvars == hcl->c->tv.wcount - saved_tv_wcount);
+
 	if (push_fnblk(hcl, HCL_CNODE_GET_LOC(src), hcl->c->tv.wcount, hcl->c->tv.s.len, hcl->code.bc.len, hcl->code.lit.len) <= -1) return -1;
 
+	tmpr_mask = ENCODE_BLK_TMPR_MASK(0, nargs, 0, nlvars);
+	
 	if (hcl->option.trait & HCL_TRAIT_INTERACTIVE)
 	{
-		/* make_function nargs ntmprs lfbase lfsize */
-		if (emit_double_param_instruction(hcl, HCL_CODE_MAKE_FUNCTION, nargs, ntmprs, HCL_CNODE_GET_LOC(cmd)) <= -1) return -1;
+		/* make_function tmpr_mask lfbase lfsize */
+		if (emit_single_param_instruction(hcl, HCL_CODE_MAKE_FUNCTION, tmpr_mask, HCL_CNODE_GET_LOC(cmd)) <= -1) return -1;
 		lfbase_pos = hcl->code.bc.len;
 		if (emit_long_param(hcl, hcl->code.lit.len - hcl->c->fnblk.info[hcl->c->fnblk.depth - 1].lfbase) <= -1) return -1; /* literal frame base */
 		lfsize_pos = hcl->code.bc.len; /* literal frame size */
@@ -1775,7 +1777,7 @@ static int compile_lambda (hcl_t* hcl, hcl_cnode_t* src, int defun)
 	}
 	else
 	{
-		if (emit_double_param_instruction(hcl, HCL_CODE_MAKE_BLOCK, nargs, ntmprs, HCL_CNODE_GET_LOC(cmd)) <= -1) return -1;
+		if (emit_single_param_instruction(hcl, HCL_CODE_MAKE_BLOCK, tmpr_mask, HCL_CNODE_GET_LOC(cmd)) <= -1) return -1;
 	}
 
 	HCL_ASSERT (hcl, hcl->code.bc.len < HCL_SMOOI_MAX);  /* guaranteed in emit_byte_instruction() */
diff --git a/lib/hcl-prv.h b/lib/hcl-prv.h
index d8513b1..65967e0 100644
--- a/lib/hcl-prv.h
+++ b/lib/hcl-prv.h
@@ -485,21 +485,45 @@ struct hcl_compiler_t
 #endif
 
 
+
+/* hcl_context_t, hcl_block_t, hcl_function_t stores the local variable information
+ * 
+ * Use up to 29 bits in a 32-bit hcl_ooi_t. Exclude the tag bit and the sign bit.
+ * | SIGN | VA | NARGS | NRVARS | NLVARS | TAG |
+ *     1    1     8       8        12        2    <= 32
+ * -----------------------------------------------------------
+ * Parameters to MAKE_BLOCK or MAKE_FUNCTION.
+ *  | VA | NARGS | NRVARS | NLVARS 
+ *    1      4      4        7         <= 16 (HCL_CODE_LONG_PARAM_SIZE 1, two params)
+ *    1      8      8        12        <= 32 (HCL_CODE_LONG_PARAM_SIZE 2, two params, use 29 bits to avoid collection when converted to a smooi)
+ */
+ 
 #if defined(HCL_CODE_LONG_PARAM_SIZE) && (HCL_CODE_LONG_PARAM_SIZE == 1)
-#	define MAX_CODE_INDEX               (0xFFu)
-#	define MAX_CODE_NTMPRS              (0xFFu)
-#	define MAX_CODE_NARGS               (0xFFu)
+/*
 #	define MAX_CODE_NBLKARGS            (0xFFu)
 #	define MAX_CODE_NBLKTMPRS           (0xFFu)
+*/
+#	define MAX_CODE_NBLKARGS            (0xFu) /* 15 */
+#	define MAX_CODE_NBLKRVARS           (0xFu) /* 15 */
+#	define MAX_CODE_NBLKLVARS           (0x7Fu) /* 127 */
+
+#	define ENCODE_BLK_TMPR_MASK(v,nargs,nrvars,nlvars) \
+		((((v) & 1) << 15) | (((nargs) & 0xF) << 11) | (((nrvars) & 0xF) << 7) | (((nlvars) & 0x7F)))
+
 #	define MAX_CODE_JUMP                (0xFFu)
 #	define MAX_CODE_PARAM               (0xFFu)
 #	define MAX_CODE_PARAM2              (0xFFFFu)
 #elif defined(HCL_CODE_LONG_PARAM_SIZE) && (HCL_CODE_LONG_PARAM_SIZE == 2)
-#	define MAX_CODE_INDEX               (0xFFFFu)
-#	define MAX_CODE_NTMPRS              (0xFFFFu)
-#	define MAX_CODE_NARGS               (0xFFFFu)
+/*
 #	define MAX_CODE_NBLKARGS            (0xFFFFu)
 #	define MAX_CODE_NBLKTMPRS           (0xFFFFu)
+*/
+#	define MAX_CODE_NBLKARGS            (0xFFu) /* 255 */
+#	define MAX_CODE_NBLKRVARS           (0xFFu) /* 255 */
+#	define MAX_CODE_NBLKLVARS           (0xFFFu) /* 4095 */
+#	define ENCODE_BLK_TMPR_MASK(v,nargs,nrvars,nlvars) \
+		((((v) & 1) << 28) | (((nargs) & 0xFF) << 20) | (((nrvars) & 0xFF) << 12) | (((nlvars) & 0xFFF)))
+	
 #	define MAX_CODE_JUMP                (0xFFFFu)
 #	define MAX_CODE_PARAM               (0xFFFFu)
 #	define MAX_CODE_PARAM2              (0xFFFFFFFFu)
@@ -508,6 +532,7 @@ struct hcl_compiler_t
 #endif
 
 
+
 /*
 ----------------------------------------------------------------------------------------------------------------
 SHORT INSTRUCTION CODE                                        LONG INSTRUCTION CODE