Updated radix-4 multiplier attached. This one has zero detection so if either input is a zero then it will only take 2 cycles to complete. Uses a bit more logic but speed is not degraded from my testing (still 120MHz). Hopefully Mark's results will agree with mine :)
The other question is, is this even beneficial? I seem to recall that zeros occur quite commonly. Even in the MIPS ISA, r0 is just a hardwired zero because of this if i remember right... so that is my justification for doing this. On Fri, August 31, 2007 1:27 pm, Timothy Normand Miller said: > That's a great page, Mark. There's a lot you can see there too, like it > demonstrates clearly things about routing, especially to/from pins. > > As for Xilinx, I think I've kinda gotten used to it over time. I have > adapted my coding style so that I am more likely to get the logic I > intend. In general, the rule of thumb I apply to chip design is that the > more you try to make the synthesizer infer (rather than telling it > directly), the more likely you are to get suboptimal results. In order > to be able to complete a design in a reasonable time, you have to strike > a balance. I use the synthesizer and timing analysis as a profiler, so I > know where to concentrate my optimization effort. > > On 8/31/07, Farhan Mohamed Ali <[EMAIL PROTECTED]> wrote: >> Thanks! So it seems to me like this compiler is a bit more consistent >> than the xilinx one. On xilinx i get rather different timing and >> utilization results between v2 and v3, even though they are logically >> the same. >> >> On Fri, August 31, 2007 11:19 am, Mark said: >>> I've posted a run-down of the multipliers so far (any important ones >>> missing?) at http://jarvin.net/opengraphics/. This includes photos >>> of the most critical path post-PAR. >>> _______________________________________________ Open-graphics >>> mailing list [email protected] >>> http://lists.duskglow.com/mailman/listinfo/open-graphics List >>> service provided by Duskglow Consulting, LLC (www.duskglow.com) >>> >>> >> >> _______________________________________________ Open-graphics mailing >> list [email protected] >> http://lists.duskglow.com/mailman/listinfo/open-graphics List service >> provided by Duskglow Consulting, LLC (www.duskglow.com) >> > > > -- Timothy Normand Miller http://www.cse.ohio-state.edu/~millerti Open > Graphics Project > >
multradix4B32_v5.v
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