Replace "muxcover -freedecode" with "muxcover -dmux=cost"

Signed-off-by: Clifford Wolf <clifford@clifford.at>

diff --git a/passes/techmap/muxcover.cc b/passes/techmap/muxcover.cc
index 7fa89bbe34b4694f91a0934ad071fb67d7a43d9e..b0722134e3bc867826757e56ad8cc7dec181f57b 100644 (file)
--- a/passes/techmap/muxcover.cc
+++ b/passes/techmap/muxcover.cc
@@ -23,6 +23,7 @@
 USING_YOSYS_NAMESPACE
 PRIVATE_NAMESPACE_BEGIN
 
+#define COST_DMUX   90
 #define COST_MUX2  100
 #define COST_MUX4  220
 #define COST_MUX8  460
@@ -57,9 +58,9 @@ struct MuxcoverWorker
        bool use_mux8;
        bool use_mux16;
        bool nodecode;
-       bool freedecode;
        bool nopartial;
 
+       int cost_dmux;
        int cost_mux2;
        int cost_mux4;
        int cost_mux8;
@@ -71,8 +72,8 @@ struct MuxcoverWorker
                use_mux8 = false;
                use_mux16 = false;
                nodecode = false;
-               freedecode = false;
                nopartial = false;
+               cost_dmux = COST_DMUX;
                cost_mux2 = COST_MUX2;
                cost_mux4 = COST_MUX4;
                cost_mux8 = COST_MUX8;
@@ -180,10 +181,7 @@ struct MuxcoverWorker
                if (A == State::Sx || B == State::Sx)
                        return 0;
 
-               if (freedecode)
-                       return 0;
-
-               return std::max((cost_mux2 / GetSize(std::get<1>(entry))) - 1, 1);
+               return cost_dmux / GetSize(std::get<1>(entry));
        }
 
        void implement_decode_mux(SigBit ctrl_bit)
@@ -620,14 +618,15 @@ struct MuxcoverPass : public Pass {
                log("        Default costs: $_MUX_ = %d, $_MUX4_ = %d,\n", COST_MUX2, COST_MUX4);
                log("                       $_MUX8_ = %d, $_MUX16_ = %d\n", COST_MUX8, COST_MUX16);
                log("\n");
+               log("    -dmux=cost\n");
+               log("        Use the specified cost for $_MUX_ cells used in decoders.\n");
+               log("        Default cost: %d\n", COST_DMUX);
+               log("\n");
                log("    -nodecode\n");
                log("        Do not insert decoder logic. This reduces the number of possible\n");
                log("        substitutions, but guarantees that the resulting circuit is not\n");
                log("        less efficient than the original circuit.\n");
                log("\n");
-               log("    -freedecode\n");
-               log("        Do not count cost for generated decode logic\n");
-               log("\n");
                log("    -nopartial\n");
                log("        Do not consider mappings that use $_MUX<N>_ to select from less\n");
                log("        than <N> different signals.\n");
@@ -641,8 +640,8 @@ struct MuxcoverPass : public Pass {
                bool use_mux8 = false;
                bool use_mux16 = false;
                bool nodecode = false;
-               bool freedecode = false;
                bool nopartial = false;
+               int cost_dmux = COST_DMUX;
                int cost_mux4 = COST_MUX4;
                int cost_mux8 = COST_MUX8;
                int cost_mux16 = COST_MUX16;
@@ -675,12 +674,12 @@ struct MuxcoverPass : public Pass {
                                }
                                continue;
                        }
-                       if (arg == "-nodecode") {
-                               nodecode = true;
+                       if (arg.size() >= 6 && arg.substr(0,6) == "-dmux=") {
+                               cost_dmux = atoi(arg.substr(6).c_str());
                                continue;
                        }
-                       if (arg == "-freedecode") {
-                               freedecode = true;
+                       if (arg == "-nodecode") {
+                               nodecode = true;
                                continue;
                        }
                        if (arg == "-nopartial") {
@@ -703,11 +702,11 @@ struct MuxcoverPass : public Pass {
                        worker.use_mux4 = use_mux4;
                        worker.use_mux8 = use_mux8;
                        worker.use_mux16 = use_mux16;
+                       worker.cost_dmux = cost_dmux;
                        worker.cost_mux4 = cost_mux4;
                        worker.cost_mux8 = cost_mux8;
                        worker.cost_mux16 = cost_mux16;
                        worker.nodecode = nodecode;
-                       worker.freedecode = freedecode;
                        worker.nopartial = nopartial;
                        worker.run();
                }