Bits are 0 by default anyway, so if they are unknown (because icestorm
is too od) but we want them at 0 ... it's not much of an issue.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Technically you can enable it independently on CORE and GLOBAL
output, but this is not exposed in the classic primitive, so
we do the same as icecube2 and enable/disable it for both output
path depending on the argument
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
This uses a new data structure for net.users that allows gaps, so
removing a port from a net is no longer an O(n) operation on the number
of users the net has.
Signed-off-by: gatecat <gatecat@ds0.me>
This replaces RelPtrs and a separate length field with a Rust-style
slice containing both a pointer and a length; with bounds checking
always enforced.
Thus iterating over these structures is both cleaner and safer.
Signed-off-by: D. Shah <dave@ds0.me>
This helps make new nextpnr compatible with old chipdbs when a parameters
goes from single bit to multi bit.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
* Instead of "patching" input_en, we completely separate config for
normal and LVDS pair.
- For normal pair, nothing changes
- For LVDS pairs, the IE/REN bits are always set as if the input buffer
are disabled. Then if input_en was set to 1 (i.e. the input is
actually for something), then we set the IoCtrl.LVDS bit.
- Also for LVDS, if input is used, pullups are forcibly disabled.
* When scanning for unused IOs, never process those part of a LVDS pair.
They will have been configured by the complement
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
During packing we replace them by standard SB_IO cells and create the
'fake' SB_GB that matches that IO site global buffer connection.
It's done in a separate pass because we need to make sure the nextpnr iob
have been dealt first so we have our final Bel location on the SB_IO.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Those are cells that are created mainly to handle the various sources a
global network can be driven from other than a user net.
When the flag is set, this means the global network usually driven by
this BEL is in fact driven by something else and so that SB_GB BEL and
matching global network can't be used.
This is also what gets used to set the extra bits during bitstream
generation.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
