Rotate accumulator left

def instruction_ROL_register(self, opcode, register):
        """ Rotate accumulator left """
        a = register.value
        r = self.ROL(a)
#        log.debug("$%x ROL %s value $%x << 1 | Carry = $%x" % (
#            self.program_counter,
#            register.name, a, r
#        ))
        register.set(r)