Mail Archives: djgpp-workers/1998/01/03/14:43:07
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
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