Re: Test suite for 6509 processor

From: Michał Pleban <lists_at_michau.name>
Date: Mon, 26 Feb 2018 11:56:23 +0100
Message-ID: <5A93E7D7.9030301@michau.name>
Hello!

smf wrote:

> From my understanding of what has been said here:
> 
> Writing to 0 in any bank will cause the 6509 to start executing code in
> another bank & there won't be any code there for it.

Yes.

> The value written to 0/1 in any bank doesn't end up in ram because the
> cpu doesn't drive the data bus.

Yes.

> When I say any bank, I mean using the indirect instructions that let you
> access data in a different bank.

One thing left to check is that when you are writing to 0/1 using
indirect instruction, does the CPU clobber memory in the execution bank
or in the bank chosen by register #1 (the latter would be more logical
IMHO)?

> It also sounds like it's impossible to read location 0/1 of any bank
> that the 8088 card has written, because it will always come from the
> bank switch registers.

Yes.

Regards,
Michau.

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Received on 2018-02-26 11:01:35

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