Path: utzoo!utgpu!water!watmath!clyde!rutgers!uwvax!oddjob!hao!noao!stsci!itkin
From: itkin@stsci.EDU (Elliot Itkin)
Newsgroups: comp.sys.amiga
Subject: Re: the Amiga Interrupt Cycle and Exec
Message-ID: <244@ra>
Date: 22 Feb 88 03:29:46 GMT
References: <8802210745.AA20230@cory.Berkeley.EDU>
Organization: Space Telescope Science Institute, Baltimore, MD 21218
Lines: 31

in article <8802210745.AA20230@cory.Berkeley.EDU>, dillon@CORY.BERKELEY.EDU (Matt Dillon) says:
 [in response to a question about the previous stack contents and what
  the exec pushes there]
> A5/A6, but what possible reason could you have for wanting the original
> contents?  

I can think of one real quick - A performance analyzer.  Generate an
interrupt every n milliseconds and in your interrupt code just record
the PC of what you interrupted.  Save this in memory and write out to
disk whenever memory is full.  If you do it right it should take very little
CPU out.  Afterwards, you run the raw PC list though an analysis program
that converts the absolute PCs into more meaning information (that's the
hard one to write).
This way you can discover many things that you could only guess at before.
This is an especially useful tool for large complex software systems
(especially real-time ones) where the place that is eating CPU cycles
is completely unknown.

Please answer the question so that this can be built.  An Amiga tool this
powerful (could the analysis program read your executable and object
files when producing its report?  A super-duper one could read your
source files and tell you how often particular lines of code were
executed!!!)  WOW golly gee.  

I hope this is what the info is wanted for, but it probably is to 
produce a super-duper pirater or something.
-- 
Elliot S. Itkin       Space Telescope Science Institute, Baltimore, MD 21218
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