Some models have I/O cells that are IOBUFs, and other types (IBUFs and
OBUFs) are obtained by feeding 1 or 0 to the OEN input. This is done
with general-purpose routing so it's best to do it here to avoid
conflicts.
For this purpose, in the new bases, these special cells are of type IOBS
(IOB Simplified).
The proposed changes are compatible with bases of previous versions of
Apycula and do not require changing .CST constraint files.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
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>
Instead of parsing the partnumber with a regular expression,
a simple table is used. This is done because the structure
of the partnumber changes as new features appear (e.g., ES instead of C6/I5)
This commit does not yet disable the very first regular expression check.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
* A hardwired MUX within each logical cell is used.
* The delay is equal 0.
* No user placement constraints.
* The output route contains dummy PIPs. They are ignored by gowin_pack, but it may be worth removing them.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
Added support for the INS_LOC instruction in the constraints file
(.CST), which is used to specify object placement.
Expanded treatment of IO_LOC/IO_PORT constraints, which now can
be applied to both ports and IO buffers.
Port constraints have priority.
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>
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>
