Posted By
gerliczer
on 2019-01-06
13:38:47
|  Re: LUMYDCTT - RenderGFX - Need some help
I think you misunderstood how FLI works, MMS. The attribute memory change does not take two raster lines, it can be done in one. But bad lines, where the TED reads attribute data, come in pairs, therefore you have to do $FF14 and $FF06 writes in every second line, unless you want colour and luminance maps mixed up. One load-store pair (sg like LDA im, STA abs) takes 6 clock cycles, so one could naively think that four updates could be done per raster line as there are up to 22+3 cycles in a bad line, but the $FF06 write must happen exactly at a specific cycle in the line which makes four register updates not feasible. AFAIK, even three is only doable with trickery.
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