5200 Splash Screen

[DanBoris]

Here's a challenge for everyone. I have the disassmbly of the 5200 bios on my page (http://atarihq.com/danb) that I have commented most of it, but for the life of me I can't figure out the part of the code that draws the startup screen with the Atari logo.

 

There are two parts to the code, $FD93 - $FE01 draw the Fuji logo, and $FE03-$FE61 draw the "ATARI". It isn't doing a straight copy of graphics data to RAM, it's using some tricky algorithm to do it.

 

Any one have any ideas on how this works?

 

Dan

[jindroush]

quote:

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Originally posted by Dan Boris:

but for the life of me I can't figure out the part of the code that draws the startup screen with the Atari logo.

 

Any one have any ideas on how this works?

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See my homepage, I posted revised 5200 disassembly which explains that.