Re: A86: A86 : Protocol additions
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Re: A86: A86 : Protocol additions
On Fri, 5 Sep 1997 Steve86Asm@aol.com wrote:
> The best way to avoid errors is to just thoroughly check your code, which
> still misses them, but I don't think a compiler or other such program would
> be able to find them... The best protection is another 86 that can send the
> files back when it crashes...
No, the best protection would be a debugger that would pretend to execute
the program and make sure that it doesn't do undesirable stuff (like
overwrite the stack). A debugger should not be much more difficult to
write than a disassembler, and I already have one of those. The question
is where to put the debugger so that _asm_exec_ram is free. Ooo! I have
an idea:
1. Relocate the debugger to some free space in RAM page 1.
2. Whenever the debuggee wants to access a different RAM page, switch
the $4000 page, do the dirty work, and switch it back.
There are still some problems with this scheme. For example, some of the
system calls change the $8000 page. Those calls would have to be emulated
somehow, or thunked by a procedure somewhere above $C000. Also, we still
don't know exactly how routines use RAM page 1. It might not be a
suitable place.
--------
Dan Eble (mailto:eble@cis.ohio-state.edu)
(http://www.cis.ohio-state.edu/~eble)
References: