On 2007-09-01, Farhan Mohamed Ali wrote: > > So, let's consider integrating Farhan's version in the nanocontroller. > > Given that the VGA code will use 16 bit, would it be better to reduce the > > multiplier to 16x16->32? Will this be insufficient for the DMA code? > > (Does DMA require multiply at all, other than powers of 2?) Conversely is > > 33 cycles multiply to slow for the VGA code, and would 17 cycles be fast > > enough? > > > > 16x16 will take 9 cycles. Perhaps it could be fast enough to be clocked > at 200mhz if it is a dedicated 16x16 part. I'll try this out. I will also > try adding a special mode to the current 32x32 version that assumes 16 > bit inputs and takes 9 cycles to complete for that mode.
To complete your corrections, the 32x32 radix-4 multiplier is 17 cycles, not 33 as I said. I think a 16x16 mode is more interesting than early-termination. Now, we're also getting down to quite manageable delays, as seen from the programmer trying to fill in the instruction slots. This also means the cycles used on I/O become more important. _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
