Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!crdgw1!crdos1!davidsen From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) Newsgroups: comp.arch Subject: Re: Bitfield instructions--a good idea? Message-ID: <3365@crdos1.crd.ge.COM> Date: 24 Apr 91 14:33:09 GMT References: <1991Apr15.193425.3436@waikato.ac.nz> <1991Apr23.053619.13474@kithrup.COM> <9104231527.AA09611@iecc.cambridge.ma.us> Reply-To: davidsen@crdos1.crd.ge.com (bill davidsen) Organization: GE Corp R&D Center, Schenectady NY Lines: 20 In article <9104231527.AA09611@iecc.cambridge.ma.us> johnl@iecc.cambridge.ma.us (John R. Levine) writes: | Recent models of screen buffer do remap all of the planes at the same | place in the address space, which makes a lot of this moot unless you can | do a page flush without a context switch. But even that's possible on the | 386 -- it does let you enable individual device addresses for user I/O. I have been waiting for frame buffers to come out with an option to map the whole thing in extended memory, say between 15-16MB. I predicted this as a popular enhancement when EGA first came out, and I was wrong. I find it hard to belive that no one has done this, since even a 286 can use it, but I don't know of anyone who has. And I'm told that the new XGA from IBM is still bank swapping so they can use an 8086. Slavish dedication to being backward. Ur, backward compatibility I meant, didn't i? -- bill davidsen (davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen) "Most of the VAX instructions are in microcode, but halt and no-op are in hardware for efficiency"