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From: apratt@atari.UUCP (Allan Pratt)
Newsgroups: comp.sys.atari.st
Subject: Re: Pexec() innards
Message-ID: <839@atari.UUCP>
Date: Fri, 11-Sep-87 17:14:21 EDT
Article-I.D.: atari.839
Posted: Fri Sep 11 17:14:21 1987
Date-Received: Sun, 13-Sep-87 20:00:21 EDT
References: <767@saturn.ucsc.edu>
Organization: Atari Corp., Sunnyvale CA
Lines: 31

in article <767@saturn.ucsc.edu>, koreth@ssyx.ucsc.edu (Steven Grimm) says:
> #include <osbind.h>
> 
> main()
> {
> 	long basepage;
> 
> 	basepage = Pexec(3, "test.tos", "", 0L);
> 	printf("basepage = %08lx\n", basepage);
> 	Pexec(4, 0L, 0L, basepage);
> 	printf("done\n");
> }

The correct call for Pexec type 4 is "Pexec(4,0L,basepage,0L);"

The combination of load/nogo plus just-go does not work reliably.
There are bugs in Pexec relating to memory ownership which cause trouble.

You should be able to determine something about where the bombs are,
though: is the PC in ROM, or less than "basepage" (i.e. in the parent),
or greater than basepage (i.e. in the child)?

I have a trick which *does* work for fooling with a child before it has
started executing, but it is ugly.  I use it in my debugger.  What are
you trying to do?  Maybe the same trick would work for you.  Mail me more
explanation.

/----------------------------------------------\
| Opinions expressed above do not necessarily  |  -- Allan Pratt, Atari Corp.
| reflect those of Atari Corp. or anyone else. |     ...lll-lcc!atari!apratt
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