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[interchange] Scale edge cost of pseudo pips.

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Previous pseudo pips were the same cost as regular pips, but this is
definitely too fast, and meant that the router was prefering them.

Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
This commit is contained in:
Keith Rothman 2021-04-01 15:18:17 -07:00
parent 9b82ded77b
commit c11ad31393
2 changed files with 12 additions and 5 deletions
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11
fpga_interchange/arch.cc
View File

@ -1959,6 +1959,17 @@ void Arch::explain_bel_status(BelId bel) const
site.explain(getCtx());
}
DelayQuad Arch::getPipDelay(PipId pip) const {
// FIXME: Implement when adding timing-driven place and route.
const auto & pip_data = pip_info(chip_info, pip);
// Scale pseudo-pips by the number of wires they consume to make them
// more expensive than a single edge. This approximation exists soley to
// make the non-timing driven solution avoid thinking that pseudo-pips
// are the same cost as regular pips.
return DelayQuad(100*(1+pip_data.pseudo_cell_wires.size()));
}
// Instance constraint templates.
template void Arch::ArchConstraints::bindBel(Arch::ArchConstraints::TagState *, const Arch::ConstraintRange);
template void Arch::ArchConstraints::unbindBel(Arch::ArchConstraints::TagState *, const Arch::ConstraintRange);

6
fpga_interchange/arch.h
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@ -622,11 +622,7 @@ struct Arch : ArchAPI<ArchRanges>
return canonical_wire(chip_info, pip.tile, loc_info(chip_info, pip).pip_data[pip.index].dst_index);
}
DelayQuad getPipDelay(PipId pip) const final
{
// FIXME: Implement when adding timing-driven place and route.
return DelayQuad(100);
}
DelayQuad getPipDelay(PipId pip) const final;
DownhillPipRange getPipsDownhill(WireId wire) const final
{