Re: [stella] Supercharger strangeness

Subject: Re: [stella] Supercharger strangeness
From: Eckhard Stolberg <Eckhard_Stolberg@xxxxxxxxxxxxxxxxxxxxx>
Date: Sat, 05 Aug 2000 13:10:05 +0200
>It seems to be related to the placement of instructions in the bank 
>switch code. ???

Like putting that code in the $F0xx area? ;-)

When SC writing is enabled, an access to an address in the $F0xx page
might trigger a write to an address a couple of address changes later.
If you execute the bankswitching code in the $F0xx page, accesses to
$FFF8 will take the value to be written from the last address that was
accessed in $F0xx. So depending on which address you put the STA $FFF8 at,
the last fetch when the processor reads that instuction might be on
an address which has the bits set for a working bankswitching/write-enable
value or not. In general it's best not to execute any code at $F0xx while
SC writing is enabled.

Ciao, Eckhard Stolberg

Archives (includes files) at
Unsub & more at

Current Thread