def instruction_BLT(self, opcode, ea):
        """
        Causes a branch if either, but not both, of the N (negative) or V
        (overflow) bits is set. That is, branch if the sign of a valid twos
        complement result is, or would be, negative. When used after a subtract
        or compare operation on twos complement binary values, this instruction
        will branch if the register was less than the memory register.

        source code forms: BLT dd; LBLT DDDD

        CC bits "HNZVC": -----
        """
        if (self.N ^ self.V) == 1: # N xor V
#            log.info("$%x BLT branch to $%x, because N XOR V == 1 \t| %s" % (
#                self.program_counter, ea, self.cfg.mem_info.get_shortest(ea)
#            ))
            self.program_counter.set(ea)