Hi! On Tue, Nov 06, 2012 at 10:15:04PM +0100, Christian Dirks wrote: > The screen scrolling seems very slow to me. > Since I haven't seen a working P500 before, I don't know, if it is > alwas that slow. Scrolling (and video output in general) is slow on the P500. Commodore seems to have had issues with accessing the VIC and the video/color RAM, so they used rather complex write routines. See the routines wrtvic, wrtvram and wrtcram in the ROM listing: http://www.von-bassewitz.de/uz/oldcomputers/p500/rom500.s.html#AALV Fortunately the routines to write the RAM are called via vectors: http://www.von-bassewitz.de/uz/oldcomputers/p500/rom500.s.html#AAL5 Since most versions of the P500 don't have the access problems, one can change the write vectors to point to simple write routines instead of the complex original ones. This will speedup the output considerately. > The ROMs are -02's. These are the latest ROMs known to exist. At least to me:-) Regards Uz -- Ullrich von Bassewitz uz@musoftware.de Message was sent through the cbm-hackers mailing listReceived on 2012-11-06 22:00:36
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