Re: Hardware emulation of 6509 using 6502?

From: Michał Pleban <*lists_at_michau.name*> Date: Sat, 04 Nov 2017 19:13:19 +0100 Message-ID: <59FE033F.1000707@michau.name> · lists_at_michau.name

Hello!

Mia Magnusson wrote:

> Maybe this is a bit too hard to actually do, but my idea is to keep
> track of what the CPU does and detect the LDA and STA Y-indirect
> instructions and then temporarily switch in the relevant bank during
> the correct cycle. 

I don't think that it should be difficult. The 6502 emits SYNC signal
when it is fetching a new opcode. It can then be checked if it's LDA/STA
(xx),Y opcode and appropriate memory bank can be switched. Nothing a
CPLD could not solve.

Regards,
Michau.

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