[Open-graphics] Documenting Hardware Design Process

[Timothy Normand Miller]

On 11/28/07, Viktor Pracht <ViktorPracht at gmx.de> wrote:
>
> What can the really expensive tools do that Icarus can't?
>

The really expensive tools are smart.  Icarus, Synplicity, ISE's
synthesizer, and other basic ones like that aren't; they just make the
most direct translation from Verilog to technology cells.  Then it's
up to P&R to make it fit.  The smart tools look ahead, consider timing
earlier in the process, and they'll refactor your logic to meet
constraints.  You know how, hypothetically, any chunk of combinatorial
logic can be converted into two levels of AND and OR gates (with some
inverters).  So if your logic doesn't meet timing, a smart tool can
see that your logic has too many layers and reorganize it so that it
has fewer (up to practical limits).  These toy FPGA tools don't do any
of that, or if they do anything like that at all, they do a lousy job
of it.

-- 
Timothy Normand Miller
http://www.cse.ohio-state.edu/~millerti
Open Graphics Project