Article View: comp.sys.transputer
Article #89Checksum on code ??
From: Emile
Date: Tue, 04 Aug 1992 15:32
Date: Tue, 04 Aug 1992 15:32
48 lines
1817 bytes
1817 bytes
Hello!
At the moment I am designing a "checksum"-module to check if the object code
of my program has for some mysterious reason changed (Believe me, some bits
are toggled by Magic). To do this, I read the .map file and scan for the
SC code line:
Example:
Processor Load Map
Processor 1 T800
Memory layout first byte last byte
Work space #8000008C #8000036B
Configuration code #8000036C #8000037F
SC code from file check.c8h #80000380 #80009E9B
No libraries loaded
Separate vector workspace #80009E9C #8001EE3B
<stuff deleted>
From this file I would read the starting address #80000380 and the last
address #800009E9B
However, the code turns out to be changed during program execution!
Appearantly, some variables (??) are stored in the code segment, making it
impossible to calculate a checksum.
My questions are:
1. Does anyone know what kind of data is stored in the code segment?
2. Is it possible to determine a stable part of the code? Preferrably a very
large part...
3. Has anyone tried something like a checksum on the code before?
4. Any more suggestions??
Thanks in advance.
Sincerely,
Emile van Gerwen
PTT Research Neher Laboratories
M.J.A.M.vanGerwen@research.ptt.nl
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Newsgroups: comp.sys.transputer Path: arc1-ca.pugleaf.net!sparky!uunet!mcsun!sun4nl!research.ptt.nl!gerwen From: gerwen@research.ptt.nl (Emile) Subject: Checksum on code ?? Message-ID: <1992Aug4.173214.1@research.ptt.nl> Sender: usenet@spider.research.ptt.nl (USEnet News) Nntp-Posting-Host: dnlts0_f Organization: PTT Research, The Netherlands Date: Tue, 4 Aug 1992 15:32:14 GMT Lines: 48