Date   : Tue, 26 Jan 1993 12:49:19 -0500
From   : Jay Sage <sage@ll.mit.edu>
Subject: Re: 8080/8085/Z80 Code Identifier

Richard Plinston added the following comment to my suggestion of using an
emulator to determine the presence or absence of Z80 opcodes in a given COM
file:

>> But it will only execute those parts of the program that are in the
>> execution path ... It may be that Z80 specific code only exists in parts
>> of the program that are not executed ...

   This is true, and I, too, thought of that at the time I composed my
message.  However, I decided not to mention it, since it is highly, highly
unlikely -- though not impossible -- that only 8080 opcodes would be used in
the main program code while a Z80 opcode would be used in exception code.

   One could come up with with a program (using self-modifying code!) that
would appear to have only 8080 opcodes except under arbitarily specific
input conditions, and to that extent there is no way, in principle, to
determine with certainty from the COM file alone that it does not and can
not contain Z80 opcodes.  However, I do not think that this is what the
person who made the original posting was thinking about; his question was
much more practical than that, and I think the emulator approach would solve
his problem very nicely and easily.