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Parametric muxcover costs as per @daveshah1

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This commit is contained in:
Eddie Hung 2019-07-08 11:08:20 -07:00
parent eb19abbb44
commit dbe1326573
1 changed files with 14 additions and 16 deletions
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30
techlibs/xilinx/synth_xilinx.cc
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@ -280,23 +280,21 @@ struct SynthXilinxPass : public ScriptPass
}
else if (widemux > 0) {
run("simplemap t:$mux");
std::string muxcover_args = " -nodecode";
constexpr int cost_mux2 = 100;
std::string muxcover_args = stringf(" -nodecode -mux2=%d", cost_mux2);
switch (widemux) {
// NB: Cost of mux2 is 100; mux8 should cost between 3 and 4
// of those so that 4:1 muxes and below are implemented
// out of mux2s
case 5: muxcover_args += " -mux8=350 -mux16=400"; break;
case 6: muxcover_args += " -mux8=450 -mux16=500"; break;
case 7: muxcover_args += " -mux8=550 -mux16=600"; break;
case 8: muxcover_args += " -mux8=650 -mux16=700"; break;
case 9: muxcover_args += " -mux16=750"; break;
case 10: muxcover_args += " -mux16=850"; break;
case 11: muxcover_args += " -mux16=950"; break;
case 12: muxcover_args += " -mux16=1050"; break;
case 13: muxcover_args += " -mux16=1150"; break;
case 14: muxcover_args += " -mux16=1250"; break;
case 15: muxcover_args += " -mux16=1350"; break;
default: muxcover_args += " -mux16=1450"; break;
case 5:
case 6:
case 7:
case 8: muxcover_args += stringf(" -mux8=%d -mux16=%d", cost_mux2*(widemux-1)-1, cost_mux2*(widemux-1)); break;
case 9:
case 10:
case 11:
case 12:
case 13:
case 14:
case 15:
default: muxcover_args += stringf(" -mux16=%d", cost_mux2*(widemux-1)-1); break;
}
run("muxcover " + muxcover_args);
}