>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 http://www.biglist.com/lists/stella/archives/
Unsub & more at http://www.biglist.com/lists/stella/
