On Thu, Nov 27, 2014 at 10:56:41AM +0100, Anders Carlsson wrote: >Groepaz wrote: > >>>Does anyone have a NES? Were undocumented opcodes used in any NES games? >>iirc the flag is ignored... and there are illegal opcodes, but they >>dont exactly match the known ones -> >>http://en.wikipedia.org/wiki/2A03 > >See also this page discussing the 6502 decimal mode, which mentions >that the 2A03 handles setting and clearing the decimal flag, but >doesn't implement the decimal mode. This is achieved by removing five >transistors in the core. > >http://visual6502.org/wiki/index.php?title=6502DecimalMode Thanks, this was the missing piece of information. Isn't it ironic how Nintendo is allowed to copy from others but not vice versa? As far as I understand, it is not a copyright violation to copy a physical item if some minor details change. It would be legal, provided that no patents, design patents or trademarks are violated either. Marko Message was sent through the cbm-hackers mailing listReceived on 2014-11-27 14:00:04
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