Re: How complex is the 6502?

[borchert@i50s19.ira.uka.de (Volker Borchert)]

In article <CGBr4p.4I4@actrix.gen.nz>, dempson@swell.actrix.gen.nz (David Empson) writes:
|> In article <CG99LM.Enu@IRO.UMontreal.CA> guertinp@IRO.UMontreal.CA (Paul Guertin) writes:
|> > A question I've been asking myself, lately:
|> >  
|> > How complex is the 6502? For example, what would a 6502 emulator made
|> > out of TTL logic look, how much would it cost, and how much power
|> > would it need?
|> 
|> The 6502 is probably one of the simplest microprocessors.  I seem to
|> recall reading somewhere that it contains about 25,000 transistors.

Must be much less. The 68000 was called 68000 because it contained
about 68000 transistors... The Z80 has, to my knowledge, 8000, and
has much more registers, etc. 2500 seems to fit better. That would
evaluate to about 800 gate equivalents, and should fit onto three
Doppeleuropa cards (160x233.4 mm�).

|> Do you want this to work as fast as a real 6502, or just a slow
|> working model?  Making sure it had the same behaviour for the
|> unimplemented instructions might be tricky!  :-)

Much faster. Say, about 28 MHz (for easy sync with the Apple's video
circuitry).

-- 

* "I'm a doctor, not a mechanic." Dr Leonard McCoy <mccoy@ncc1701.starfleet.fed> *
* "I'm a mechanic, not a doctor." Volker Borchert <borchert@ira.uka.de>          *