diff --git a/assembler/assembler.py b/assembler/assembler.py
index ffd0b0c..3942ad1 100755
--- a/assembler/assembler.py
+++ b/assembler/assembler.py
@@ -6,8 +6,8 @@
 import time
 
 atable, ltable, dtable, vtable = {}, {}, {}, [] #initialize global tables
-address_size = 4
-jump_size = 7
+address_size = fields_table["address"]
+jump_size = fields_table["jump"]
 
 try:
     filename = sys.argv[1]
diff --git a/assembler/tables.py b/assembler/tables.py
index 53028f6..b4cf0d3 100644
--- a/assembler/tables.py
+++ b/assembler/tables.py
@@ -14,3 +14,9 @@
     "unused" :  32, 
     "data"   :  16
 }
+
+fields_table = {
+    "opcode"  : 4,
+    "address" : 4,
+    "jump"    : 7
+}