Re: Apple IIe Enhancement Kit

[Don Bruder <dakidd@sonic.net>]

In article <eKadna7a37l4_87fRVn-pw@comcast.com>,
 "Bill Garber" <willy46pa@comcast.net> wrote:

> "Michael J. Mahon" <mjmahon@aol.com> wrote in message
> HoqdnVrIzOsaws7fRVn-pg@comcast.com">news:HoqdnVrIzOsaws7fRVn-pg@comcast.com...
> : Don Bruder wrote:
> : > In article <1112745624.538457.263650@o13g2000cwo.googlegroups.com>,
> :
> : [ snipped ]
> :
> : > Character ROM chip (for the "Mousetext" characters), 2 monitor ROM chips
> : > that include a couple of bug-fixes and the return of the
> : > "mini-assembler", plus a 65C02 processor with several machine-language
> : > instructions that the "regular" 6502 didn't have.
> :
> : Most of my machines have 65C02's, but some don't.  I have never found
> : the additional instructions of the 65C02 sufficiently compelling to
> : warrant writing programs that are incompatible with 6502s.
> :
> : It isn't like they added a multiply or something!  ;-)
> 
> They don't really do much more than make the code incompatible
> with the 6502, and btw, the "C" stands for "C" if you can make
> my extra codes worthwhile.   :o)

It's been a while since I did anything in 6502/65C02 assembly, so my 
memory is foggy (and that's putting it nicely!) but I seem to recall one 
of them being *EXTREMELY* useful for a project I worked on. Can't 
rememebr which one it was, though. Without that instruction, code size 
would have been quite a bit bigger, and a WHOLE BUNCH (to the tune of 
"completely unacceptable") slower, since replacing it with "straight" 
6502 instructions to accomplish the same task would have been about a 
12-byte-per-replacement proposition. Never mind the "spaghetti" effect 
that would have crept in due to the "substitution".

It *COULD* have been done in "pure" 6502, I'm quite sure, but doing so 
would have been majorly ugly.

-- 
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