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ZeroMung.doc.pp
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ZeroMung.doc
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1990-02-08
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ZeroMung.doc JDGJr 900125
John D. Gerlach, Jr.
3615 Barcroft View Terrace
Apt #104
Falls Church, VA 22041
bix: jgerlachjr
This small(?) program is a QUICK coding of a useful debugging tool.
It does only one thing: It modifies the value at location zero !!!!
------------------------------------------------------------------
Some programs currently available make use of the following condition
in most Amiga computers:
*0 == 0L
This dependence should be interpreted as a BUG.
If a program, or a piece of hardware happens to put a non-zero value into
location zero, odd things may begin to occur inside programs depending
on this anomoly. Noticed symptoms include:
- drastic slowing of program execution
- improper execution of minor areas of a program
- major inabilities to function properly.
WARNING: This program either clears or sets location zero. Plan for
messages from either MemWatch, WatchMem, or any similar program if they
are running.
Usage: ZeroMung [option]
If any parameters are passed, location zero is set to 0xFEFEFEFE.
If NO parameters are passed, location zero is cleared to zero.
The status of location zero is displayed before these modifications
are made.
ZeroMung may be placed in your startup-sequence BEFORE any memory-
watchers to set or clear location zero everytime the machine is
booted.
This program was written to debug a situation presented by a bad ROM on
a HD controller card. The auto-booting board was modifying location
zero before any memory-watcher had the slightest chance of noticing.
------------------------------------------------------------------
Use in peace and harmony, and let software authors know when they've
screwed up!