Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!apple!baum@apple.com From: baum@apple.com (Allen Baum) Newsgroups: comp.arch Subject: more cache/uncached ld/st Message-ID: <51903@apple.Apple.COM> Date: 23 Apr 91 22:45:17 GMT References: <1991Apr15.193425.3436@waikato.ac.nz> <1991Apr23.053619.13474@kithrup.COM> <1991Apr23.152155.2298@zoo.toronto.edu> Sender: nntp@Apple.COM Organization: Apple Computer Lines: 13 In article <1991Apr23.152155.2298@zoo.toronto.edu>, henry@zoo.toronto.edu (Henry Spencer) writes: > > Anybody who caches a frame buffer is crazy. Especially if the cache isn't > write-through, in which case your frame-buffer updates show up on the screen > some arbitrary time later! > Not so. If you can use the burst transfer into the cache, and throw away the line (i.e. burst dump it) when finished, its a very large win. Of course, you need cache management instructions, and your graphics algorithms have to have a pretty good idea of how much of a cache line they're going to munge. For moving windows around, for example, you have a very good idea, and it pays.