Le 05.09.2012 12:52, Groepaz a écrit : > > err, no - the PCE uses a NEC "HuC6280" CPU, which is "6502 like", but contains > a bunch of rather specific extension which can not be found in any other CPU > (eg block copy, paging support) > > an actual 65C02 can be found in the NES aka famicom :) > > that said, only the 6502 (and 6510) contains such "secret" (as in > undocumented) instructions. the opcode matrix of the 65C02 is completely > defined (and further undocumented instructions replaced by either NOP or > actual new instructions) >
You are right - I assumed the PC-Engine Hu CPU was just a 65C02 with some extra hardware, but it appears to have custom instructions. The NES does not technically contain a 6502 but a 2A03 or 2A07 (NTSC/PAL), both of which contains the die of a regular 6502, lacking decimal mode as it was pointed out. Sounds like it will be more complicated than I expected to handle all these variants properly and to test them (assuming the goal is to produce the most efficient code possible on any given variant), but the plain 6502 is a must-start (since all other variants can run plain 6502 code just fine). ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Sdcc-user mailing list Sdcc-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/sdcc-user
