[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: 6502 illegal opcodes questions



Bruce Tomlin wrote:
In article <kKCdnXMGZogpR_XZRVn-qw@comcast.com>,
 "Michael J. Mahon" <mjmahon@aol.com> wrote:


My mistake--from this chip photo, I incorrectly identified either
the registers or the ALU as a PLA:

http://micro.magnet.fsu.edu/chipshots/mos/6502large.html


See that mess of spaghetti in the middle? I think that's the instruction decoder.

It would actually be fun to see the real logic diagram of the
6502.  ;-)

All of the "internals" documentation I've found is very abstract
with no detail where it would be most interesting.

-michael

Music synthesis for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it is seriously underused."