Re: Difference between R65C02 and original 6502 (wrt 6509 emulation)

From: Michał Pleban <lists_at_michau.name>
Date: Wed, 17 Apr 2019 13:06:17 +0200
Message-ID: <5CB708A9.7080406_at_michau.name>
Mia Magnusson wrote:

> What I'm trying to say is that if the registers at 0 and 1 are hidden
> from read, but listens to writes, in '816 mode, everything should work
> fine as the code that switches back from '816 mode to 6509 emulation
> could just write the 0/1 registers at $F0000/$F0001 as there is no risk
> of corrupting memory for the 8088 board. With those registers written
> it's then safe to switch back from '816 mode to 6509 emulation mode and
> the registers will contain the correct values even if previous code had
> written to $x0000/$x0001.

I suppose if we go the route to switch to the '816 mode to write to
memory, then switch back to the 6502 mode to call the KERNAL, then it
should probably be quite easy for the IPC code to make sure that the CPU
is found in correct bank when it is switched back to the 6502 mode?

Regards,
Michau.
Received on 2020-05-29 21:31:57

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