From: Stefan Reinauer (stepan@suse.de)
Date: Tue 02 Mar 1999 - 00:56:12 IST
Hi... I started making a motherboard independant version of svgalib for alpha AXP. The problem of current implementations is that you have to compile a new version for each motherboard type and that newer motherboards like the 164LX and 164UX don't work properly. Well.. my implementation is still in it's beginnings and the patch I applied now to this mail is not even a bit cleaned up. It's just the current q&d state of the art. As far as my understanding of Alpha AXP architecture is, there are different types of memory access: a) Sparse memory. This is a quite old type of memory access. The framebuffer of a graphics device is not mapped at a single position but cut into several pieces, like patches. b) Dense Memory. This allows a "linear framebuffer access". This dense memory can be accessed in 8/16/32/64 bit accesses on some machines but only in 32/64 bit aligned accesses on others Now, there are different kinds of motherboards: a) Some have only Sparse Memory Architecture. Afaik, this are only "Jensen Boards" b) Some have both, allowing Dense memory access in 8bit accesses as well (164LX, Multia) c) Some have both, allowing Dense memory access only in 32/64 bit accesses (164UX) d) Some (EV6) have only dense memory and only allow 32/64 bit aligned access. (dp264) At the current time only type b) is tested and maybe a) works. c) and d) still need to be worked on, but that ought to be trivial. (Well I thought, the whole concept of alpha memory architecture is trivial when I started) Some of my code is "stolen" from glibc and XFree. Just to mention it. Regards, Stefan Reinauer(stepan@suse.de) -- SuSE GmbH Can you afford *NOT* Schanzäckerstr. 10 to use Linux? D-90443 Nürnberg Germany AlphaPowered
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