Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site watmath.UUCP
Path: utzoo!watmath!hhoeksma
From: hhoeksma@watmath.UUCP (Henry Hoeksma)
Newsgroups: net.micro.pc
Subject: Bug in MASM 3.0 and therefore Lattice 2.15.
Message-ID: <15959@watmath.UUCP>
Date: Thu, 1-Aug-85 01:22:55 EDT
Article-I.D.: watmath.15959
Posted: Thu Aug  1 01:22:55 1985
Date-Received: Fri, 2-Aug-85 00:26:05 EDT
Distribution: net
Organization: U of Waterloo, Ontario
Lines: 11

The Lattice 2.15C that I just bought has a library function called
movmem() that doesn't seem to work.  Programs which use it tend to
crash randomly.  (This is for the S-model, but probably applies to
the other models as well.)  I disassembled movmem() and discovered
that it used the instruction REPZ MOVSB, when it should have been
REP MOVSB.  I then wrote my own movmem() with the correct REP prefix,
and to my surprise, when I disassembled the resulting object file
it contained the REPZ prefix!  It seems that MASM 3.0 (from MicroSoft)
generates the wrong opcode for the REP - namely a REPZ.
Assembler and C programmers beware!