Where possible at least, and disable-able with `-nocteval`.
`$lcu` doesn't work because it uses ports `P, G, CI, CO` instead of the standard `A, B, C, Y`.
`$alu` and `$fa` have more than one output so they don't work either (and in the case of `$alu` it has extra inputs too).
`$macc` is at least supported, but `CellTypes::eval()` doesn't have an implementation so it fails (which would also be true for `$lcu`, `$alu`, and `$fa`; if they weren't being rejected based on ports).
Also add `test_cell -list [all|evaluable|missing]` which prints the list of cell types supported by test_cell, cell types marked evaluable, and cell types marked evaluable but not supported by test_cell respectively. Potential for listing cell types supported by test_cell but *not* marked evalulable, though that list is currently empty.
Add `tests/various/evaluable.sh` to exercise this.
Looks up the cell type for each cell in the design, returning the value of `CellType::is_<property>`.
Only works for exact match, and only for internal cells.
Also add a simple test checking a small design with an $add cell and an $sdff cell.
The B port is for single-bit summands. These can just as well be
represented as an additional summand on the A port (which supports
summands of arbitrary width). An upcoming `$macc_v2` cell won't be
special-casing single-bit summands in any way.
In preparation, make the following changes:
* remove the `bit_ports` field from the `Macc` helper (instead add any
single-bit summands to `ports` next to other summands)
* leave `B` empty on cells emitted from `Macc::to_cell`
Previously the `abc9_box` mode was reserved to modules with the
`blackbox` or `whitebox` attribute. Allow `abc9_box` on ordinary modules
when doing hierarchical synthesis.
`abc9_ops -prep_box` command interprets the `abc9_box` attribute and
prepares a .box file for ABC consumption. Previously this command was
removing the attribute as it was processing each module which prevented
repeated invocation of this command unless the box definitions were
refreshed from a source file.
Also the command was keeping existing `abc9_box_id` attributes instead
of overwriting them with values from a new number sequence.
Change both behaviors to allow repeated invocations of the command on
the same design.
