Am Sonntag, 30. August 2020, 14:23:27 CEST schrieb Marko Mäkelä: > On Fri, Aug 28, 2020 at 11:52:36PM +0100, smf wrote: > >You can do that, but registers aren't really what you would consider > >ram. The 4 bit color ram doesn't particularly count either. > > > >Try executing code stored there. > > BTDT, about 26 years ago. You should still be able to find my program > "dadb" somewhere, and it should work on a decent emulator. Most of the > time, the program is executing RTS instructions that are half fetched > from the color RAM, half from the normal RAM by the previous VIC-II half > cycle. The stack is filled with $da, which will cause the RTS to jump > to $dadb. It took me a week to write the program, because unlike with > the predecessor program that was running in open address space ($de00 to > $dfff), also the least significant address bits matter. Sometimes, the > program would have to fetch a non-zero nibble from the color RAM, so > that it could change the screen color depending on whether the space bar > was being held down. here: https://sourceforge.net/p/vice-emu/code/HEAD/tree/testprogs/C64/openio/ ;) -- http://hitmen.eu http://ar.pokefinder.org http://vice-emu.sourceforge.net http://magicdisk.untergrund.net Unix *is* user-friendly; it's just picky about its friends.Received on 2020-08-30 15:02:12
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