diff options
Diffstat (limited to 'ice40')
| -rw-r--r-- | ice40/arch.cc | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/ice40/arch.cc b/ice40/arch.cc index f008b617..eb26ae5a 100644 --- a/ice40/arch.cc +++ b/ice40/arch.cc @@ -865,15 +865,22 @@ TimingPortClass Arch::getPortTimingClass(const CellInfo *cell, IdString port, Id return TMG_COMB_INPUT; if (port == id_COUT || port == id_LO) return TMG_COMB_OUTPUT; - if (cell->lcInfo.dffEnable) { - clockPort = id_CLK; - if (port == id_O) + if (port == id_O) { + // LCs with no inputs are constant drivers + if (cell->lcInfo.inputCount == 0) + return TMG_IGNORE; + if (cell->lcInfo.dffEnable) { + clockPort = id_CLK; return TMG_REGISTER_OUTPUT; + } else - return TMG_REGISTER_INPUT; - } else { - if (port == id_O) return TMG_COMB_OUTPUT; + } + else { + if (cell->lcInfo.dffEnable) { + clockPort = id_CLK; + return TMG_REGISTER_INPUT; + } else return TMG_COMB_INPUT; } |