The following cells are supported by this pass (ie. will be ingested,
and can be specified as allowed targets):
- $_DFF_[NP]_
- $_DFFE_[NP][NP]_
- $_DFF_[NP][NP][01]_
- $_DFFE_[NP][NP][01][NP]_
- $_ALDFF_[NP][NP]_
- $_ALDFFE_[NP][NP][NP]_
- $_DFFSR_[NP][NP][NP]_
- $_DFFSRE_[NP][NP][NP][NP]_
- $_SDFF_[NP][NP][01]_
- $_SDFFE_[NP][NP][01][NP]_
- $_SDFFCE_[NP][NP][01][NP]_
- $_SR_[NP][NP]_
- $_DLATCH_[NP]_
- $_DLATCH_[NP][NP][01]_
- $_DLATCHSR_[NP][NP][NP]_
The following transformations are performed by this pass:
- upconversion from a less capable cell to a more capable cell, if the less
capable cell is not supported (eg. dff -> dffe, or adff -> dffsr)
- unmapping FFs with clock enable (due to unsupported cell type or -mince)
- unmapping FFs with sync reset (due to unsupported cell type or -minsrst)
- adding inverters on the control pins (due to unsupported polarity)
- adding inverters on the D and Q pins and inverting the init/reset values
(due to unsupported init or reset value)
- converting sr into adlatch (by tying D to 1 and using E as set input)
- emulating unsupported dffsr cell by adff + adff + sr + mux
- emulating unsupported dlatchsr cell by adlatch + adlatch + sr + mux
- emulating adff when the (reset, init) value combination is unsupported by
dff + adff + dlatch + mux
- emulating adlatch when the (reset, init) value combination is unsupported by
- dlatch + adlatch + dlatch + mux
If the pass is unable to realize a given cell type (eg. adff when only plain dff
is available), an error is raised.