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From: hatcher@INGRES.BERKELEY.EDU (Doug Merritt)
Newsgroups: comp.sys.amiga
Subject: 6502 Vs 68000, lets get it straight .
Message-ID: <8703100226.AA07627@ingres.Berkeley.EDU>
Date: Mon, 9-Mar-87 21:26:26 EST
Article-I.D.: ingres.8703100226.AA07627
Posted: Mon Mar  9 21:26:26 1987
Date-Received: Tue, 10-Mar-87 19:05:06 EST
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Organization: University of California at Berkeley
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Matt Dillon wants to straighten us all out on how much faster a 68000
is than a 6502. What he says seems to be good information, but it misses
the entire point that George Robbins (and I and others) are trying to make.

The point is not how fast you can do things on one versus the other.
That is different than doing an emulation.

The point is how hard it is to do an emulation. Go re-read George's two
postings. They are totally accurate and to the point, and do not deserve
being misunderstood.

To put it another way, if you are going to write software that *TRANSLATES*
a 6502 program into an equivalent 68000 program, then you can probably
get a 68000 program that is as fast or faster than the 6502 program. But
nobody is planning that, because it is extraordinarily difficult. That is
a vastly different thing than doing an emulator.

An emulator need only understand each individual effect of each instruction
of the target machine.

A translator needs to be able to understand the OVERALL effect of arbitrary
groups of instructions, and be able to WRITE NEW CODE in the new machine
that has the same effect.

Now, I won't discourage you from doing this. I think intelligent translators
are pretty cool. But don't underestimate the work involved. It is considerably
harder than just writing a mere C compiler, for instance. At least, it is
if you want any kind of optimized output. I suppose that if you don't care
how optimized the output is, then it's not too hard. Note that in this case,
you end up with an emulator again, and not a fast one, since it just puts
the emulation of each instruction in-line in the output program.

So although Matt and others have some good points, they are addressing
a different subject than "what about all that 6502 software out there".
	Doug