--- a/python/cortexm3.py	Sun Sep 29 14:08:15 2013 +0200
+++ b/python/cortexm3.py	Sat Oct 12 09:56:23 2013 +0200
@@ -218,6 +218,16 @@
     def __repr__(self):
         return 'DCD 0x{0:X}'.format(self.expr)
 
+@armtarget.instruction
+class nop_ins(ArmInstruction):
+    mnemonic = 'nop'
+    operands = tuple()
+
+    def encode(self):
+        return bytes()
+
+    def __repr__(self):
+        return 'NOP'
 
 
 # Memory related
@@ -299,6 +309,7 @@
     def encode(self):
         rt = self.rt.num
         assert rt < 8
+        assert self.offset % 4 == 0
         imm8 = self.offset >> 2
         assert imm8 < 256
         assert imm8 >= 0
@@ -434,7 +445,7 @@
 class mulregreg_ins(ArmInstruction):
     """ mul Rn, Rdm """
     operands = (Reg8Op, Reg8Op)
-    mnemonic = 'mul'
+    mnemonic = 'MUL'
     def __init__(self, rn, rdm):
         self.rn = rn
         self.rdm = rdm