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SubjectRe: NES scrolling  
Posted bymcmartin
Posted on5/31/02 04:32 AM
From IP12.234.128.26  



Are you approaching this from an "I want scrolling to work right in my emulator" sense?

There's an internal 16-bit pointer into VRAM which is modified by writes to $2000, $2005, and $2006. Loopy's documents show which bits in the even/odd writes to $2005/$2006 modify which bits of that pointer. It then discusses how the pointer is modified during non-VBLANK. All the Weird Scrolling Tricks wind up falling directly out of those patterns.



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Entire Thread
Subject  Posted byPosted On
*NES scrolling  elm_775/30/02 08:17 AM
..Re: NES scrolling  mcmartin5/31/02 04:32 AM
..*Re: NES scrolling  elm_775/31/02 08:05 AM
...*Re: NES scrolling  mcmartin5/31/02 10:01 PM
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