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Date   : Tue, 07 Dec 2004 14:42:24 +0000 (GMT)
From   : Tom Walker <tommowalker@...>
Subject: Re: mode switching

> Beware of writing directly to &FE20.  If the OS IRQ
> handlers *ever* get a
> look in, they will return ?&FE20 back to what they
> think it should be for
> the current mode.  This is weird but seems to happen
> for some reason (on a
> Master at least).

This is done to update the flashing colours (which are
determined by bit 0 of &FE20). You could work around
this by altering the RAM copy instead (&248 on OS 1.2)
but I'm not sure if this is the same for all versions.

Tom


               
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