During the years I came across chips designated 65C02 which did not have the bit manipulation etc. "new" instructions. Clearly, there were several second-sourcing companies, some of them might have chosen to designate a 6502-like design as "C" simply to stress the CMOS technology.
Also, according to wikipedia, NES contains a derivative which lacks the BCD mode. http://en.wikipedia.org/wiki/Ricoh_2A03 All I want to say is that there are variants which should perhaps be considered when planning a 65x02 port. JW ----- Original Message --------------- Subject: Re: [Sdcc-user] Adding support for the 6502 processor From: Groepaz <groe...@gmx.net> Date: Wed, 5 Sep 2012 12:52:24 +0200 To: sdcc-user@lists.sourceforge.net >On Wednesday 05 September 2012, Masur Jonathan wrote: >> > Also, as a remark, the 6502 has a derivative, the 65C02; of which >> > there also exists variants with "secret" (more or less officially >> > supported) instructions. >> >> Exact, the 65C02 has some extra instructions. It is used in the >> TurboGraphix-16 / PC-Engine video game console. > >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) ------------------------------------------------------------------------------ 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
