extract_counter: Allow forbidding async reset

diff --git a/passes/techmap/extract_counter.cc b/passes/techmap/extract_counter.cc
index 5e4fc7c8a64dd764a677a32056bef34da6328068..9186b7696f1ae0999188953d066aabb25c746320 100644 (file)
--- a/passes/techmap/extract_counter.cc
+++ b/passes/techmap/extract_counter.cc
@@ -111,6 +111,7 @@ struct CounterExtractionSettings
        pool<RTLIL::IdString>& parallel_cells;
        int maxwidth;
        int minwidth;
+       bool allow_arst;
 };
 
 //attempt to extract a counter centered on the given adder cell
@@ -241,6 +242,9 @@ int counter_tryextract(
                extract.has_reset = false;
        else if(count_reg->type == ID($adff))
        {
+               if (!settings.allow_arst)
+                       return 25;
+
                extract.has_reset = true;
 
                //Check polarity of reset - we may have to add an inverter later on!
@@ -395,7 +399,7 @@ void counter_worker(
        //Do nothing, unless extraction was forced in which case give an error
        if(reason != 0)
        {
-               static const char* reasons[25]=
+               static const char* reasons[]=
                {
                        "no problem",                                                                   //0
                        "counter is too large/small",                                   //1
@@ -421,7 +425,8 @@ void counter_worker(
                        "Underflow value is not equal to init value",   //21
                        "RESERVED, not implemented",                                    //22, kept for compatibility but not used anymore
                        "Reset is not to zero or COUNT_TO",                             //23
-                       "Clock enable configuration is unsupported"             //24
+                       "Clock enable configuration is unsupported",    //24
+                       "Async reset used but not permitted"                    //25
                };
 
                if(force_extract)
@@ -579,6 +584,9 @@ struct ExtractCounterPass : public Pass {
                log("    -minwidth N\n");
                log("        Only extract counters at least N bits wide (default 2)\n");
                log("\n");
+               log("    -allow_arst yes|no\n");
+               log("        Allow counters to have async reset (default yes)\n");
+               log("\n");
                log("    -pout X,Y,...\n");
                log("        Only allow parallel output from the counter to the listed cell types\n");
                log("        (if not specified, parallel outputs are not restricted)\n");
@@ -595,6 +603,7 @@ struct ExtractCounterPass : public Pass {
                        .parallel_cells = _parallel_cells,
                        .maxwidth = 64,
                        .minwidth = 2,
+                       .allow_arst = true,
                };
 
                size_t argidx;
@@ -635,6 +644,12 @@ struct ExtractCounterPass : public Pass {
                                settings.minwidth = atoi(args[++argidx].c_str());
                                continue;
                        }
+
+                       if (args[argidx] == "-allow_arst" && argidx+1 < args.size())
+                       {
+                               settings.allow_arst = args[++argidx] == "yes";
+                               continue;
+                       }
                }
                extra_args(args, argidx, design);