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Yeah. When I was a kid I hit on a relative addressing bug in the 6502 processor. I wrote a fast screen scroll routine in assembler but it just did not work pro
by MattPalmer1086 4y ago
Yeah. When I was a kid I hit on a relative addressing bug in the 6502 processor. I wrote a fast screen scroll routine in assembler but it just did not work properly.
It was inconceivable to me that the hardware was at fault. I just assumed I didn't understand it well enough, and this was pre internet so there were no other sources of information.
- _the_inflator 4y agoVSP or what is the $d011 trickery called that can move the screen from left to right. It is only after 25+ years that I found out on CSDB, that there were several CPU revisions that made the effect somewhat tricky in itself.
- MattPalmer1086 4y agoHuh I never knew about that one. Seems to be a C64 hack. I had a Tangerine Microtan 65: https://en.m.wikipedia.org/wiki/Tangerine_Microtan_65 https://en.m.wikipedia.org/wiki/Tangerine_Microtan_65 It was amazing what people did with hardware back then.