Subject: [stella] ? memory ? From: Thomas Dunn <td629@xxxxxxxxx> Date: Thu, 19 Jul 2001 11:46:40 -0700 (PDT) |
Hello all, I am new to 2600 programming, I have been reading the Stella Programmers Guide and the stuff at Nick Bensema's page. I don't really know anything about hardware, but I've had a little assembly experience. I WANT TO WRITE A GAME :) I have a few questions about memory in stella programming. Some of the things I will write are statements, hoping you'll correct me if I'm wrong. TIA --- You write to TIA addresses or registers for graphics, etc. Are these really registers, or is it just some memory space. Is this really in the TIA, or is it writing into the 6502's memory? If its really in the TIA, why can I say $06 for COLUP0 and not have it just reference the the 6th byte in the 6502's memory? 6502 ---- The 6502 has 65535 byte-sized locations. Where is it safe to store stuff without messing up other stuff? PIA --- In the PIA part of the Stella guide, it says "The PIA has 128 bytes of RAM located in the Stella memory map from HEX address 80 to FF." So the PIA writes to memory on the 6502 to get its work done, right? It also says the stack is normally located from FF on down The book I got out of the library, _6502 Software Design_ by Leo Scanlon says the stack is in $0100 thru $01FF which seems to contradict what the Stella guide says. Is this a difference in the 6502 vs 6507? program memory -------------- I get that your program and game data is in the .bin file, or on the cartridge. When you turn on the 2600, I suppose it just starts reading the first byte off the cartridge? (maybe after doing a little initialization ?) I've seen stuff about different cartridge sizes, 4K 8K etc what are the space limitations for the game? I thank those who've taken the time to read my questions, Tom Dunn __________________________________________________ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail http://personal.mail.yahoo.com/ - Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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