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Old 27 August 2009, 14:34   #19
Jgames
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Join Date: Mar 2009
Location: UK
Posts: 338
I've done some search on the cartdrige games, the wiki says this
Quote:
" In most cases the designs were fairly crude, with the entire address and data buses exposed by the port; the cartridge was memory mapped directly into the system's address space"
http://en.wikipedia.org/wiki/ROM_cartridge
This means, the cartrige is considered as RAM in the console, or the computer. It's accessed like a read only RAM to be more correct; It's like having a game from floppy already loaded to ram.
This means that writing a rom game, variables declaration must be explicitly put in a region where the ram is read and write; (the small ram the console have)
So the rom games are executed directly from the rom;

now the question i would like an answer to is how the double buffering is done, if the amount of ram is much lesser than memory needed for a full screen dispaly mode?
Maybe as i pointed before, most consoles don't do double buffering, and write directly to Vram?, or write to a non displayable portion of Vram and flip (change address) to this vram when wanting to display; like DOS Modex (that uses 256 kb of vram, making it capable of using 4 pages of 64kb 320*200 screens), but this needs a lot of ram (256kb) to do that.

Anyone can help?
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