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archapi: Use arbitrary rather than actual placement in predictDelay

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This makes predictDelay be based on an arbitrary belpin pair rather
than a arc of a net based on cell placement. This way 'what-if'
decisions can be evaluated without actually changing placement;
potentially useful for parallel placement.

A new helper predictArcDelay behaves like the old predictDelay to
minimise the impact on existing passes; only arches need be updated.

Signed-off-by: gatecat <gatecat@ds0.me>
This commit is contained in:
gatecat
2021-12-19 16:41:34 +00:00
parent 56d5507333
commit ddb084e9a8
26 changed files with 89 additions and 70 deletions
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9
generic/arch.cc
View File

@@ -509,11 +509,12 @@ delay_t Arch::estimateDelay(WireId src, WireId dst) const
return (dx + dy) * args.delayScale + args.delayOffset;
}
delay_t Arch::predictDelay(const NetInfo *net_info, const PortRef &sink) const
delay_t Arch::predictDelay(BelId src_bel, IdString src_pin, BelId dst_bel, IdString dst_pin) const
{
const auto &driver = net_info->driver;
auto driver_loc = getBelLocation(driver.cell->bel);
auto sink_loc = getBelLocation(sink.cell->bel);
NPNR_UNUSED(src_pin);
NPNR_UNUSED(dst_pin);
auto driver_loc = getBelLocation(src_bel);
auto sink_loc = getBelLocation(dst_bel);
int dx = abs(sink_loc.x - driver_loc.x);
int dy = abs(sink_loc.y - driver_loc.y);

2
generic/arch.h
View File

@@ -287,7 +287,7 @@ struct Arch : ArchAPI<ArchRanges>
const std::vector<GroupId> &getGroupGroups(GroupId group) const override;
delay_t estimateDelay(WireId src, WireId dst) const override;
delay_t predictDelay(const NetInfo *net_info, const PortRef &sink) const override;
delay_t predictDelay(BelId src_bel, IdString src_pin, BelId dst_bel, IdString dst_pin) const override;
delay_t getDelayEpsilon() const override { return 0.001; }
delay_t getRipupDelayPenalty() const override { return 0.015; }
float getDelayNS(delay_t v) const override { return v; }