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From: ifarqhar@sunb.mqcc.mq.oz.au (Ian Farquhar)
Newsgroups: comp.sys.amiga.emulations
Subject: Re: Emulator Mechanics (sorry long post)
Message-ID: <1323@macuni.mqcc.mq.oz>
Date: 10 Mar 91 03:33:49 GMT
References: <4992@mindlink.UUCP> <1991Mar6.004247.8964@cpsc.ucalgary.ca> <2406@taurus.BITNET>
Sender: news@macuni.mqcc.mq.oz
Organization: Macquarie University, Sydney, Australia.
Lines: 27

In article <2406@taurus.BITNET> finkel%math.tau.ac.il@CUNYVM.CUNY.EDU (Udi Finkelstein) writes:
>as someone who wrote a 8085 emulator/disassembler/monitor for the C64
>I would like to contribute my on thoughts on the subject.

A 8085 toolkit on a C64?  The mind boggles.  Why?! :-)

>2. self modifying code breaks such schemes easily

I have yet to see a piece of self-modifying code on an IBM PC, and it
will cause problems on the many 386DX and 486 systems that have instruction 
caches without write-through.

>What I really wanted to do if I had an MMU based machine is to write an
>emulator that will use the MMU to track such memory accesses. The emulator's
>memory will be referenced without translation, but every address in the range
>where the video memory is located will be caught by the MMU and special code
>will be run to handle it. This would speed things up.

Check my article on using lots of memory to very quickly tag this
occurence on non-PMMU systems, by vectoring every location to a
handler.

--
Ian Farquhar                      Phone : + 61 2 805-9400
Office of Computing Services      Fax   : + 61 2 805-7433
Macquarie University  NSW  2109   Also  : + 61 2 805-7420
Australia                         EMail : ifarqhar@suna.mqcc.mq.oz.au