From: "John S. Fine" <johnfine AT erols DOT com>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Some assembly questions
Date: Thu, 18 Mar 1999 17:00:10 -0500
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Martin Str|mberg wrote:

> Perhaps somebody can inform me on the difference (if there is one)
> between "cmpl $1, %eax" and "testl $1, %eax".

  CMP internally does a SUB, discarding the result and keeping
only the condition codes from the result.

  TEST internally does an AND, discarding the result and keeping
only the condition codes from the result.

  Since SUB is very different from AND, CMP is very different from
TEST.  For example, cmpl $1 will set the Z-bit only if the entire
target is equal to one.  testl $1 will set the Z-bit if the target
is any even number.
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