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Re: R65C02 PI
- Subject: Re: R65C02 PI
- From: shack@deimos.frii.com (Randy Shackelford)
- Date: 1996/08/27
- Newsgroups: comp.sys.apple2
- Organization: Front Range Internet, Inc, Fort Collins, Colorado
- References: <4vd6qq$8qt@newsbf02.news.aol.com> <4vh2j7$8kq@darla.visi.com> <4vmegd$b6p@nnrp1.news.primenet.com> <322252E2.678C@cup.hp.com>
In article <322252E2.678C@cup.hp.com>, Michael Mahon <mahon@cup.hp.com> wrote:
>John Bowling wrote:
>I was never a big game fan, so there may be a lot of stuff out there
>that uses undocumented opcodes, but I sure haven't seen it!
>
>The one trick I _have_ seen is the JSR-to-last-byte-of-page, but
>that 6502 bug was fixed in the 65C02, so //c's and enhanced //e's
>wouldn't be able to run even _those_ programs!
I think you mean JMP indirect, it's the one whose operand can't cross a
page boundary on a 6502.
>Since there has been little outcry about //c and //e game compatibility,
>I conclude that undocumented opcodes are not a major issue.
>
>Does anyone have a list of programs that are so affected?
All the old games which I have tried with the exception of One on One work
on a //c and IIgs for that matter.
--
Randy Shackelford US Air Force officer
shack@frii.com and Apple aficionado