diff --git a/source/assembler.c b/source/assembler.c
index 2c7e13c..e60a6af 100644
--- a/source/assembler.c
+++ b/source/assembler.c
@@ -290,14 +290,21 @@ static void build_move (size_index size,
 	print ((to == MEM) && (from == IMM), size, source);
 }
 
-next   token_count;
-byte * token_array;
+next   token_count = 0;
+byte * token_array = NULL;
+
+int error_empty_array = 0;
 
 void assemble (next   count,
                next * array) {
 	/* */
 	next index;
 
+	if ((count == 0) || (array == NULL)) {
+		error_empty_array = 1;
+		return;
+	}
+
 	for (index = 0; index < count; ++index) {
 		if ((array [index] >= REGULAR_BEGIN)
 		&&  (array [index] <= REGULAR_END)) {
diff --git a/source/assembler.h b/source/assembler.h
index 888948d..d3a94a2 100644
--- a/source/assembler.h
+++ b/source/assembler.h
@@ -65,6 +65,8 @@ typedef enum {
 extern next   token_count;
 extern byte * token_array;
 
+extern int error_empty_array;
+
 extern void assemble (next count, next * array);
 
 #define ASSEMBLER_H