IIGS tech questions...

["RedskullDC" <redskulldc@oohay.moc.ua>]

Hi All,

I've scoured the IIGS tech manuals for any information on these
2 topics, but none of them seem to go into the detail I was hoping for.

Can anyone help with these before I resort to the logic analyzer?

1. In superhires modes (either 320 or 640x200) when *exactly* does the
video hardware re-read the SCB/palette information for each line about to be
displayed, and in what order?

The SCB for the line to be displayed would have to be read first to 
ascertain
exactly which colour palette has to be loaded, and also whether an interrupt
has to be generated for the line in question.

Does the video hardware buffer the pallette bytes before the line is 
displayed,
(implying that the pallette for the line to be displayed is fixed) or does 
it do a
read of screen data, then another read of the pallette on the fly (allowing
pallette changes mid-line)?

I'm guessing that it reads the SCB then palette data on the negative 
transition
of the Horiz sync pulse, though it could be anywhere in the front/back 
porch,
horiz sync area.

2. Do the read/write main/alt softswitches only affect bank 00, or
do they affect all even numbered RAM banks? (except E0/E1)

For instance, if I have readALT turned on, and I read $02/1000,
will I get the contents of $03/1000?

I know the whole main/alt setup is unnecessary when running in 65816
native mode.

Cheers,
Red