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Re: 65816/GS - move SHGR memory?

On 11/8/2012 8:53 PM, Steve Nickolas wrote:

On Thu, 8 Nov 2012, Charlie wrote:


Maybe I'm missing something in this discussion but can't you just
BLOAD your picture into bank $00 and use the AUXMOVE routine at $C311
to move the picture to bank $01. If shadowing isn't inhibited (it
rarely is but you can check the shadow register at $C035) then $E1 and
$01 contain the same data. Then turn on SHR with softswitch $C029.
No 16-bit code should be necessary to move or display SHR.


Hm. That may be possible (I have my own version of AUXMOVE that I use in
QIX).

In my experiments a few years ago, though, sometimes fiddling with data
in bank $01 using 65C02 code didn't have the results on bank $E1.


From the IIgs Firmware Reference:
"When shadowing is enabled, whenever the Apple IIGS writes into bank $00 (or bank $01), the system automatically synchronizes with the Mega II and writes the same data into bank $E0 (or bank $E1)."
I will back off on what I said about the shadowing rarely being inhibited because while playing with moving picture data in the monitor (in 8 bit mode) something had set the 'inhibit SHR shadow bit' in $C035 (bit 3). I reset it and was able to move data from bank $00 to $01 via the monitor commands and it shadowed to bank $E1 and displayed on the screen. 

Charlie