Disallow LOCK prefix for non-lockable instructions

parseinstrs.py

@@ -37,6 +37,7 @@ InstrFlags = bitstruct("InstrFlags", [
     "gp_size_def64:1",
     "gp_instr_width:1",
     "gp_fixed_operand_size:3",
+    "lock:1",
 ])
 assert InstrFlags._encode_size <= 32
 
@@ -113,6 +114,7 @@ class InstrDesc(namedtuple("InstrDesc", "mnemonic,flags,encoding")):
         if "SIZE_8" in desc[6:]:      flags.gp_size_8 = 1
         if "INSTR_WIDTH" in desc[6:]: flags.gp_instr_width = 1
         if "IMM_8" in desc[6:]:       flags.imm_byte = 1
+        if "LOCK" in desc[6:]:        flags.lock = 1
 
         return cls(desc[5], frozenset(desc[6:]), flags._encode())
     def encode(self, mnemonics_lut):