Re: [cc65] Any targets with a 65C02 CPU out there?

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From: Groepaz (groepaz_at_gmx.net)
Date: 2003-05-02 23:08:20


On Friday 02 May 2003 22:02, Ullrich von Bassewitz wrote:
> > i would also be interisted in someone who is using cc65 with a 65c02
> > target, since compiling stuff for the pcengine proved to be a problem
> > lately :( (it may just be that my knowledge of pcengine is to little
> > though :=P)
>
> Can you track it down to some a piece of code or a subroutine?

i havent really examined this in detail yet to be honest :O) i just noticed 
that tetris stopped working at a certain point when i recompile a "none.lib" 
with the current snapshot. (strange enough, it still works with the none.lib 
i compiled long long ago). i'm suspecting this is an error on my side though, 
as you said you didnt change anything in the 65c02 related parts of the 
compiler lately....have to do some more testing with more trivial test 
routines :)

> > [*] am i right with the assumption that adding those opcodes to the
> > assembler would be basically a matter of copying/editing a certain table?
> > might do that some time when i am sick of pce-stuff not working again :=P
>
> Yes. However, since the CPU seems to be quite rare, maybe a set of macros
> are a better solution.

yes i've started some .... there is a problem however, that cpu not only adds 
a few new opcodes, it also adds some new adressing modes to existing opcodes. 
(for example the very useful non-indexed indirect load/store, ie lda($02) 
(without the ,y)).... this cant be nicely implemented with macros i think.

btw loosely related to this... i once thought it would be nice to have an 
assembler commandline option that makes the assembler forget about all and 
every opcode, so you could even abuse it (and also, the whole rest of the 
toolkit) for a completely different cpu just by writing some macros. (i 
wouldnt mind a decent assembler for the gameboy work hehe). maybe --cpu=none 
could do just this? would be a fancy feature imho :=)

> BTW: What is a PCEngine?

PCEngine is a console once produced by NEC, mostly known to fans of japanese 
roleplaying games (like zelda etc)[*]. its IMHO the most fancy piece of 
hardware you can get from the 8bit days, that 6502ish cpu is very cool 
(things like block-transfer commands really really come in handy :=)), lots 
of (unfortunatly banked) memory (rom) and a *cd rom* drive :O) 

http://www.zeograd.com/parse.php?src=hucf

check this site if you want to know more... there exists also a c-compiler for 
the pcengine, maybe you want to check that for inspiration or sth :) (dunno 
how good it works though, havent used that one...its looks to me as if its 
neither lcc nor small-c, so it might actually be interisting to check)

gpz

[*] the entire hardware actually suffers from the slow 8bit cpu (the rest 
could perform way better if just the cpu could deal with it), so many games 
were done that dont need to much cpu power, but on the other hand benefit 
from the storage space on the cd-rom by using lots and lots of nice 
graphics...those roleplaying games are the prime example :) there are however 
also some kickass shooters... the whole thing somehow feels like a c64 on 
steroids :)

mmh, not to forget they go for insane prices these days and original games are 
close to impossible to find :/
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