Specifying pin placement with this notation (e.g. IOR4B) allows
to use the same constraint file without changes for different
packages and even different families.
The vendor router also understands this notation.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
This replaces the arch-specific DelayInfo structure with new DelayPair
(min/max only) and DelayQuad (min/max for both rise and fall) structures
that form part of common code.
This further reduces the amount of arch-specific code; and also provides
useful data structures for timing analysis which will need to delay
with pairs/quads of delays as it is improved.
While there may be a small performance cost to arches that didn't
separate the rise/fall cases (arches that aren't currently separating
the min/max cases just need to be fixed...) in DelayInfo, my expectation
is that inlining will mean this doesn't make much difference.
Signed-off-by: gatecat <gatecat@ds0.me>
This Arch API dates from when we were first working out how to
implement placement validity checking, and in practice is little used by
the core parts of placer1/HeAP and the Arch implementation involves a
lot of duplication with isBelLocationValid.
In the short term; placement validity checking is better served by the
combination of checkBelAvail and isValidBelForCellType before placement;
followed by isBelLocationValid after placement (potentially after
moving/swapping multiple cells).
Longer term, removing this API makes things a bit cleaner for a new
validity checking API.
Signed-off-by: gatecat <gatecat@ds0.me>
This is a basic implementation, without considering "M of N"
arrangements (e.g. for LUT permuation where you only want to route to 1
out of 4/6 sinks) or using a type other than IdString to identify bel
pins.
But this is also enough to start working out where in nextpnr will break
due to removing the 1:1 cell:bel pin cardinality, as a next step.
Signed-off-by: gatecat <gatecat@ds0.me>
Single argument constructors will silently convert to that type. This
is typically not the right thing to do. For example, the nexus and
ice40 arch_pybindings.h files were incorrectly parsing bel name strings,
etc.
Signed-off-by: Keith Rothman <537074+litghost@users.noreply.github.com>
