Added "dfflibmap -prepare" help

diff --git a/passes/techmap/dfflibmap.cc b/passes/techmap/dfflibmap.cc
index 58f0c25427b6e7e31279d6ebb0c277e12d146daf..cc6f97c7e991cbc9e8cf7a4004e6e2a42a953c01 100644 (file)
--- a/passes/techmap/dfflibmap.cc
+++ b/passes/techmap/dfflibmap.cc
@@ -457,7 +457,7 @@ struct DfflibmapPass : public Pass {
        virtual void help()
        {
                log("\n");
-               log("    dfflibmap -liberty <file> [selection]\n");
+               log("    dfflibmap [-prepare] -liberty <file> [selection]\n");
                log("\n");
                log("Map internal flip-flop cells to the flip-flop cells in the technology\n");
                log("library specified in the given liberty file.\n");
@@ -465,6 +465,10 @@ struct DfflibmapPass : public Pass {
                log("This pass may add inverters as needed. Therefore it is recommended to\n");
                log("first run this pass and then map the logic paths to the target technology.\n");
                log("\n");
+               log("When called with -prepare, this command will convert the internal FF cells\n");
+               log("to the internal cell types that best match the cells found in the given\n");
+               log("liberty file.\n");
+               log("\n");
        }
        virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
        {