Title:			ZPP
Author:			Alun Jones <auj@aber.ac.uk>
Version:		1.00
Title From:		Documentation
Author From:		Documentation
Version From:		Documentation
Supplier:		Alun Jones <auj@aber.ac.uk>
Date:			22/04/96
Keywords:		Memory management software
Shareware:		No
Machine:		Archimedes
Operating system:	RISCOS
Memory requirements:	
Peripherals needed:	
Other s/ware needed:	
Directory:		micros/arch/riscos/e099
Date mounted/updated:	31/05/96
File names:		zpp.zip
Unarchived files:	3
Unarchived size:	2 kbytes
Omissions:		
See also:		

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Acquiring the package:

Download the archive file(s) and extract using SparkPlug 2
(see the "tools_help" file in micros/arch/riscos/tools for further info).


Description:

Zpp is a simple utility which alters the MEMC mappings on ARM 2xx and 3xx
machines to prevent user-mode writes to locations less than 0x8000. Well-
behaved programs shouldn't write here, and all OS routines which write to
these locations do so in privileged modes.  ZPP prevents (for example) NULL
pointer dereferences from crashing the machine. Rather, they cause an
address exception and a stack backtrace in the guilty program.