Harvard vs. vonNeuman

From: Bert Thomas <bert_at_brothom.nl>
Date: Tue Sep 28 03:22:59 2004

ben franchuk wrote:
>
> Peter C. Wallace wrote:
> > Isn't self modifying code pretty much deprecated these days (aside from
> > trampolines and such)
>
> So what is a trampoline?
> > Peter Wallace
>
> I have yet to see a good use for self-modifying code. Other than
> subroutines and interupts placing data into a code segement the only
> self modifying code I have seen was for the 8088.

ISTR I saw it in two area's:

- delay loop calibration -> delay routine contains a number of nops,
jump instruction moves 'upward' depending on amount of delay required in
the loop.
- one program contained some jump instructions that were replaced by
nops (or vice-versa) when a dongle was detected.

Found by reverse engineering some DOS software.

Bert
Received on Tue Sep 28 2004 - 03:22:59 BST