Date: Sat, 3 Jan 1998 11:39:57 -0800 (PST)
Message-Id: <199801031939.LAA26837@adit.ap.net>
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To: DJ Delorie <dj AT delorie DOT com>, Vik DOT Heyndrickx AT rug DOT ac DOT be
From: Nate Eldredge <eldredge AT ap DOT net>
Subject: Re: minor bug in stub for 2.02
Cc: djgpp-workers AT delorie DOT com
Precedence: bulk

At 11:43  1/1/1998 -0500, DJ Delorie wrote:

>Just before the loop (where the rep/scasb is that skips to the null)
>there's a "db 0xa9".  What's that for?  Well, the first time through,
>that byte turns the "rep scasb" into "test ax,..." and the next opcode
>is the compare for PATH.  The end result is that the first thing it
>does is look for "PATH", *not* scan for the null!
>
>This is faster and shorter than coding a "jmp check_path_first" just
>before the "scan_environment" label.
>
>Note that this means at the end of the loop, we (effectively) jump
>into the middle of an opcode!
Egad! Mel lives!

(Jargon file, appendix A)

Nate Eldredge
eldredge AT ap DOT net