On 5/26/05, Alexander van Heukelum <[EMAIL PROTECTED]> wrote: > Hi! > > Would it be an option to do all drawing in a line-by-line fashion?
What do you mean? That video memory would be accessed linearly? That is the general idea. > For > the bios graphics modes, each line occupies more or less contiguous > memory in the vga buffer (worst case is 1280 bytes per line for > mode 13h, because it's only using every 4th byte of every vga plane). > For non-bios modes (including the win95 splashscreen), the memory > access would sometimes need to be split in two because of strange > address wraps. For text modes, caching the character set(s) would be > beneficial. Worst case here is 512 characters of 32 bytes each: 16kb > total. Could this amount of memory be allocated on the fpga? There's no reason to store the VGA memory on-chip. We're fast enough that we can put it in graphics memory. I think, however, that even done poorly, the translation code will be fast enough, but if every instruction involves a lookup to execute, that'll come out too slow. In order to make memory reads efficient enough for the nanocontroller, the read instructions should be split in two. One instruction (like a prefetch) requests the memory, and another pulls it out of a FIFO. You can then write the code to absorb some of the latency. _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
