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From: ss@wivax.UUCP (Sid Shapiro)
Newsgroups: net.lang
Subject: Re: Self-modifying code
Message-ID: <19070@wivax.UUCP>
Date: Thu, 5-Jan-84 14:37:36 EST
Article-I.D.: wivax.19070
Posted: Thu Jan  5 14:37:36 1984
Date-Received: Fri, 6-Jan-84 02:43:25 EST
References: <2157@fortune.UUCP>
Organization: Wang Institute, Tyngsboro, Ma.  01879
Lines: 20

I can think of yet-another-good-reason for self-modifying code.
Execution profilers:

Without having access to the compiler code, I had to write an execution
profiler.  To do this I had the user insert one init-type routine as
the first executable statement.  The initializer then skipped through
memory saving and replacing all of the subroutine calls, function
calls, etc. with calls to a counter/timer  init routines.  The returns
returned to the counter and the final user exit really returned to the
report writer.  (It was fun to write!)

True, it was done in assembly language, but without access to the
compiler, or writing a new simulator, how would YOU create a
profiler?
-- 

Sid Shapiro -- Wang Institute of Graduate Studies
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