Re: Hardware emulation of 6509 using 6502?

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Wed, 15 Nov 2017 14:21:56 +0100 Message-ID: <cf3b54c5-144a-0a3e-f6d7-5204c17ad0d4@laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 11/15/2017 02:16 PM, smf wrote:
> On 15/11/2017 11:48, Gerrit Heitsch wrote:
>> Illegal Opcodes were never guaranteed. If you want those to work, you 
>> have to stick to 6502 from MOS, everyone else might have made small 
>> changes to the mask or the process which caused some illegal opcodes 
>> to behave differently.
> 
> In terms of the second source suppliers, I believe they were under 
> contractual obligation to produce exactly what MOS told them & if there 
> are variances then you'll see them in MOS chips too.

Does this still apply to chips made after CSG/MOS went out of business? 
Also, I have doubts about the later 6502 still being NMOS.

  Gerrit

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