From: kawakami AT mita DOT nel DOT co DOT jp
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: .exe file format
Date: Thu, 26 Oct 95 20:07:21 +0900


In Message-Id: <173B73316E AT fs2 DOT mt DOT umist DOT ac DOT uk> 
"A.Appleyard" <A DOT APPLEYARD AT fs2 DOT mt DOT umist DOT ac DOT uk> wrote: 

>Aaron Ucko <UCKO AT VAX1 DOT ROCKHURST DOT EDU> wrote (Subject: Re: GNAT-ADA-DOS bugs?):-
>
>> ... DOS actually treats COMs and EXEs equally, trying to parse an EXE header
>> if the first two bytes are 'M' and 'Z' (not necessarily in that order!) and
>> just executing the contents of the file as raw code otherwise.
>
>Where anywhere at all can I find information on the internal format and layout
>of .COM and .EXE etc files?
>
>If a .COM file did start with `MZ' or `ZM', would that correspond with any
>legal or likely PC instructions?

`M' and `Z' are `dec bp' and `pop dx' in x86 instruction.  I have no
idea to write a program which starts with these instructions.
--------
KAWAKAMI Akira <kawakami AT mita DOT nel DOT co DOT jp>
NTT Electronics Technology Corporation, Japan.