diff options
Diffstat (limited to 'passes/pmgen/ice40_wrapcarry.cc')
| -rw-r--r-- | passes/pmgen/ice40_wrapcarry.cc | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/passes/pmgen/ice40_wrapcarry.cc b/passes/pmgen/ice40_wrapcarry.cc index b84790d8f..8b3cf38bb 100644 --- a/passes/pmgen/ice40_wrapcarry.cc +++ b/passes/pmgen/ice40_wrapcarry.cc @@ -51,6 +51,9 @@ void create_ice40_wrapcarry(ice40_wrapcarry_pm &pm) cell->setParam("\\LUT", st.lut->getParam("\\LUT_INIT")); cell->attributes = std::move(st.carry->attributes); + auto it = cell->attributes.find(ID::keep); + if (it != cell->attributes.end() && !it->second.as_bool()) + cell->attributes.erase(it); cell->attributes.insert(st.lut->attributes.begin(), st.lut->attributes.end()); pm.autoremove(st.carry); @@ -69,6 +72,11 @@ struct Ice40WrapCarryPass : public Pass { log("into an internal $__ICE40_CARRY_WRAPPER cell for preservation across technology\n"); log("mapping."); log("\n"); + log("Attributes on both cells will be merged, with SB_CARRY attributes having priority\n"); + log("over SB_LUT4 attributes, except when (* keep *) attributes present on the SB_CARRY4\n"); + log("that logically evaluate to false will be dropped (thus allowing the keep attribute,\n"); + log("if any, on the SB_LUT4 to be adopted).\n"); + log("\n"); } void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE { |