Subj : IOPL code with Watcom C
To   : Vitus Jensen
From : Jonathan de Boyne Pollard
Date : Sat Dec 16 2000 08:32 am

 VJ>>>                 mov     eax,INB                ; 0x000E0000

 JdBP>> If that really *isn't* a call gate (double-check it) then I suspect
 JdBP>> a linker problem.  Dump the executable and look at the fixups for
 JdBP>> the page containing that particular piece of code.

 VJ> There is only one answer: how?  

You picked the right tool, EXEHDR, anyway, so I won't bother answering that 
question. (-:

 VJ> Watcom debugger, expect memory: entering 0x000E:0000 tells me I'm at
 VJ> INB+0  and the hex dump shows all the correct opcodes.

That would indicate that 0x000E is the actual code selector for that segment 
rather than a call gate.  So the next thing to find is the part of the LX file 
that represents the above MOV instruction.

 VJ> Now I need to check where the calls to INB are located?  Inside page 4. 
 VJ> exehdr mmpdemo.exe /v:

 VJ> page 4            type         offset     target
 VJ> obj  4:0000       16:16 PTR    0033       object    1 offset 0000 alias
 VJ>                   16:16 PTR    005a       object    1 offset 0028 alias
 VJ>                   16:16 PTR    0075       object    1 offset 0000 alias
 VJ>                   16:16 PTR    0099       object    1 offset 0028 alias

I'll have to double-check, but that doesn't look like a correct fixup.  

 ¯ JdeBP ®

--- FleetStreet 1.22 NR
 * Origin: JdeBP's point, using Squish <yuk!> (2:257/609.3)

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