[hatari-devel] Palette register handling in TT emulation

["Roger Burrows" <rfburrows@xxxxxxxxx>]

I'm working on improving TT video support in EmuTOS and I'm using Hatari 1.9 
under Linux for testing.

I was trying to understand the interaction between the ST(e)-compatible palette 
registers and the TT palette registers, so I wrote a test program and ran it on 
my TT.  It seems that (assuming the bank# in the TT shifter control is 0), the 
first 16 TT palette registers map directly to the ST(e)-compatible registers, 
and vice versa.

If that's correct, then I think that Hatari is doing it wrong.  When I write to 
e.g. 0x00ff8242 (ST palette register 1), the word at 0x00ff8402 (TT palette 
register 1) isn't updated immediately.  Similarly, writing to TT Palette 
register 1 doesn't update ST palette register 1 immediately.  This is different 
from real hardware.

Roger Burrows