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From: jwbirdsa@amc-gw.amc.com (James Birdsall)
Newsgroups: comp.os.msdos.programmer,comp.sys.ibm.pc.misc
Subject: Re: TASM bug? (no, not at all)
Message-ID: <2974@amc-gw.amc.com>
Date: 5 Sep 90 20:10:48 GMT
References: <4691@bdt.UUCP> <38580@shemp.CS.UCLA.EDU> <2953@amc-gw.amc.com> <1990Sep5.013539.22227@maytag.waterloo.edu>
Reply-To: jwbirdsa@europa.amc.com (James Birdsall)
Distribution: na
Organization: Applied Microsystems, Redmond, WA
Lines: 25

In article <1990Sep5.013539.22227@maytag.waterloo.edu> dmurdoch@watstat.waterloo.edu (Duncan Murdoch) writes:
>In article <2953@amc-gw.amc.com> I wrote:
>>   There's also MOVZX, an obscure instruction that is available on all 80x86.
>>It will extend a byte to a word, zeroing the high byte. I don't know how the
>>execution time compares to an XOR/MOV pair, but I suspect it is faster.
>>   Unfortunately, the complementary instruction (MOVSX, move with sign
>>extend) is only available on the 386.
>
>MOVZX is only available in TASM in 386 mode, and doesn't seem to work on my
>8086.  Is there some special encoding that TASM doesn't know about to get
>it to work there, or do you mean all 80x86 except mine?

   That's *interesting.* It occurs to me that to date I haven't tried to
assemble the file I used MOVZX in, so I have only some docs' word that it's
on all 80x86. The real TASM manuals are in one of N boxes (side effect of
moving across the continent), so I'm stuck with Tom Swan's _Mastering Turbo
Asssembler_, and it sounds like it has some errors...

   Sorry to have spread misinformation.

-- 
---
James W. Birdsall        jwbirdsa@amc.com         71261.1731@compuserve.com
          Compu$erve: 71261,1731            GEnie: J.BIRDSALL2
For it is the doom of men that they forget. -- Merlin