From:	"Lawrence Rust" <lvr AT NOsoftSPsystemAM DOT co DOT uk>
Newsgroups:	comp.os.msdos.djgpp
References:	<Pine DOT SUN DOT 3 DOT 91 DOT 1010417142859 DOT 12338A-100000 AT is>
Subject:	Re: Using MASM generated COFF files with GPP (solution)
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Date:	Tue, 17 Apr 2001 13:05:56 +0100
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"Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il> wrote in message
news:Pine DOT SUN DOT 3 DOT 91 DOT 1010417142859 DOT 12338A-100000 AT is...

> Then how come Tom's program worked?

I haven't seen the actual program that Tom used but I presume that the code
made no use of local static data or external subroutine calls.


> I'm hearing these two different types of reports for quite some time
> now.  Some people tell that they can link MASM-produced COFF object files
> with no problems, others tell that the relocations are wrong and must be
> patched manually.  It almost sounds as if there are two different
> versions of MASM out there.
>
> Perhaps someone could set the record straight once and for all.
>
> TIA

I've tried various versions of ml.exe and found that all of them generate
relocations incompatible with ld.  I've tested versions 6.11d (from the
Win98 & NT4 DDK), 6.13.8204 (from the Win2k DDK) and 6.14.8444 (from the
WinMe DDK).  I've found the best to be version 6.14.8444 which comes with
the Windows ME extensions for the Windows 2000 DDK, found in
\DDKWIN2K\BIN\WIN_ME\BIN\ML.EXE.

I've found that:

1. A call to an external subroutine is assembled as an 0E8h opcode followed
by a relative offset (initially 0).  A REL32 relocation record is created
pointing to the offset.  'ld' incorrectly calculates the displacement to the
target because it ignores the offset of the fixup within the section.

2. References to local static data are assembled with a section relative
address and a DIR32 relocation record.  'ld' incorrectly calculates the
virtual address because it subtracts the relative section offset from it.


> > I wrote a simple utility to do this which can be downloaded
> > (with C source) from www.softsystem.co.uk/masm2djg.zip
>
> Please consider uploading it to DJ Delorie's server (see section 22.8 of
> the DJGPP FAQ for the details), so that your utility could be put on
> SimTel.NET mirrors, where all DJGPP users could easily get it, even if
> your home page somehow becomes invalid.  Thanks.

Done.

-- Lawrence Rust
Software Systems www.softsystem.co.uk

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