A logic analyzer according to the subject invention includes a disassembler for disassembling object code. The disassembler automates the process of locating op-code addresses by utilizing information derived from an object file corresponding to the code whose execution is being disassembled. The object file includes addresses for the starting location of op-codes corresponding to individual source code lines. When the disassembler cannot determine the correct starting location for an op-code, it uses information from the object file to obtain the address of an op-code within a specified range of interest.