Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!rex!ames!eos!data.nas.nasa.gov!mustang!nntp-server.caltech.edu!toddpw From: toddpw@nntp-server.caltech.edu (Todd P. Whitesel) Newsgroups: comp.sys.apple2 Subject: Re: Stripes Message-ID: <1991Feb5.122542.2153@nntp-server.caltech.edu> Date: 5 Feb 91 12:25:42 GMT References: Organization: California Institute of Technology, Pasadena Lines: 38 gt0t+@andrew.cmu.edu (Gregory Ross Thompson) writes: > Well, the horizontal beam register really flies. You can't do much >at all with it, and what you can do is VERY CPU intensive. So, having >different colored text would be really hard. In fact, I think the >best you'd be able to do is maybe, MAYBE have it change the color >every 7 characters or so. It's 3 40-column characters. 2 is possible, but you can't get stable positioning because of a logic hack in the FPI chip. When the CPU is in fast mode, the refresh counter for the main DRAMs runs independently and does not take advantage of I/O accesses when it could. I've verified that this is the case by testing code that would produce a stable display if this weren't true -- but it wiggled. > That horizontal counter flies like a bat >out of hell. To use it at all, you have to put the GS in slow mode, >read the register, execute a bunch of NOP's depending on what the >value of the register is, and then change the color. Kinda rough. Nah, it's not too bad. I've figured out how to install a task in the heartbeat queue that maintains a display at the bottom of the screen in the border during normal system operation -- this is subject to interrupt conditions, however, so disk, AppleTalk, and usually mouse activity near the bottom of the screen can cause it to flicker. But it NEVER moves. It either appears where it's supposed to or it doesn't. Eventually I will be making this into a border clock NDA or something like that -- it does affect system performance somewhat so I wouldn't expect anybody to keep it up all the time. But it does impress the Mac people who know anything about programming. Actually, I've been thinking about writing a generic display facility for border color hacks -- say, a sort of bordercolor character driver? Reroute 12/ to .BORDER and everything pumped to stderr zooms by in the border... Todd Whitesel toddpw @ tybalt.caltech.edu