diff --git a/assembler/assembler.py b/assembler/assembler.py
index 10e6b7a..abf574b 100644
--- a/assembler/assembler.py
+++ b/assembler/assembler.py
@@ -102,6 +102,7 @@ class VMAssembler:
         """
         Intel syntax -> REG, IMM
         """
+        print(instruction.args)
         opcode = instruction.opcode
         reg = instruction.args[0]
         imm = instruction.args[1]
@@ -268,14 +269,18 @@ class VMFunction:
             line = code[i]
             ins = instruction_re.match(line)
             label = label_re.match(line)
+            print(line)
             if label:
                 label_name = label.group(1)
+                print("APPENDING {} TO {}".format(code[i], self.name))
                 self.instructions.append(VMInstruction(code[i+1], label_name))
                 i += 2
             elif ins:
+                print("APPENDING {} TO {}".format(code[i], self.name))
                 self.instructions.append(VMInstruction(line))
+            else:
+                raise InvalidOperation(line)
             i+=1
-
         self.calc_size()
 
     def calc_size(self):
@@ -317,9 +322,11 @@ class VMInstruction:
         self.opcode = next((x for x in ops if x.name == opcode), None)
         if self.opcode == None:
             raise InvalidOperation(opcode)
-
+        
         args = [x for x in ins.groups()[1:] if x is not None]
+        print(args)
         for a in args:
+            print(a)
             if immediate_re.match(a) or symcall:
                 # directly append the immediate
                 self.args.append(VMComponent(a, a))
@@ -443,7 +450,7 @@ ops = [VMComponent(le[0], i, le[1]) for i, le in enumerate(op_names)]
 regs = [VMComponent(s.casefold(), i) for i, s in enumerate(reg_names)]
 instruction_re = re.compile("^([\w]{4})(?:\ +(?:([\w]+)\ *(?:,[\ ]*([\w]+))*))?$") # 1: opcode 2+: args
 function_re = re.compile("(?:def\ )([a-zA-Z]*)\:")
-immediate_re = re.compile("(?:0x)?[0-9]*[0-9]$")
+immediate_re = re.compile("(?:0x)?[0-9a-fA-F]+$")
 alpha_re = re.compile("^[a-zA-Z]*$")
 register_re = re.compile("(^[rRsS][0-4]$)|([iIrRsS][pP]$)")
 label_re = re.compile("^([a-zA-Z]+)\:$")