Create a netlistsvg skin with routing muxes and logic muxes

[mithro]

Logic and routing muxes should look different in the diagrams generated.

[mithro]

Vivado draws routing muxes like this;

And user controlled muxes like this;

Obviously the user controlled mux is a standard symbol, but the routing mux is not and a bit stupid. Lets not copy their symbol and instead come up with a better on.

[mithro]

The difference between a routing and logic mux is if the select signal is controllable via logic or are place and route time. I think doing something which shows that is probably a good idea.

[wifasoi]

What about this?

The only think need is create a pattern

    <pattern
       id="Hatch"
       width="4"
       height="4"
       patternTransform="rotate(-45 0 0)"
       patternUnits="userSpaceOnUse">
      <line
         x1="0"
         y1="0"
         x2="0"
         y2="4"
         style="stroke:black; stroke-width:1;fill:black;"/>
    </pattern>

and apply to the polygon with:

style=fill:url(#Hatch)

but i did not tested it with netlistsvg yet

[wifasoi]

@mithro if the symbol is ok, I'll precede to create a skin for netlistsvg; but I need more information, like a yosys netlist example with some routing muxes in it (or the name of the block, inputs, and output) and where put all my work.

[mithro]

@daveshah1 Could you help @wifasoi with getting the needed information?

[daveshah1]

From Yosys's POV both a routing mux and a logic mux are the same cell type (but a routing mux will be fed from a constant - parameters are resolved to a constant before elaboration, and the logic mux from an input). Any mux will be comprised of a cascade of $mux cells internally.

However, he mux_gen.py script, which can be assumed to be used for all muxes, will always instantiate a MUXn primitive inside a mux's simulation model. These build larger muxes out of MUX2.

Probably the best way forward would be to create separate Verilog models inside the vpr/muxes/logic and a newly created vpr/muxes/routing folder for logic and routing muxes; and modify mux_gen.py to use these accordingly. Then netlistsvg skins could be created for all of these.

[mithro]

Sounds like a good plan!