RE: [stella] Maybe silly BS idea...

Subject: RE: [stella] Maybe silly BS idea...
From: "Ronen Habot" <rhabot@xxxxxxxxxxxxxxxxxxx>
Date: Fri, 6 Dec 2002 08:02:57 -0500
Hi Manuel.

> If, in theory, I'd switch banks with
> LDA $FFF9 for example
> and on FFF9 the value 'XX' is located
> would then, on the other side, the Accu carry 'XX'?!?

I think that this would work if the value you want to place into A is located in the page you are jumping to. 
As far as I understand, the uP has to read 3 opcodes for the LDA command. It is then executing the instruction. When it executes the instruction, the address but will contain the BS address and the page will change while this command is still executing. Therefore, A will contain a value read from that address in the other page. This assumes that the BS hardware latches the page bit (A0 that becomes A12 for the EPROM) at the beginning of the cycle.


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