Implement $countones, $isunknown and $onehot{,0}

diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index 1594877711669c3bd02506f1e264005f2b40d2c6..5c4dd290f7b8640b110c98d00776da145fb84872 100644 (file)
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -3148,6 +3148,34 @@ skip_dynamic_range_lvalue_expansion:;
                                goto apply_newNode;
                        }
 
+                       if (str == "\\$countones" || str == "\\$isunknown" || str == "\\$onehot" || str == "\\$onehot0") {
+                               if (children.size() != 1)
+                                       log_file_error(filename, location.first_line, "System function %s got %d arguments, expected 1.\n",
+                                                       RTLIL::unescape_id(str).c_str(), int(children.size()));
+
+                               AstNode *countbits = clone();
+                               countbits->str = "\\$countbits";
+
+                               if (str == "\\$countones") {
+                                       countbits->children.push_back(mkconst_bits({RTLIL::State::S1}, false));
+                                       newNode = countbits;
+                               } else if (str == "\\$isunknown") {
+                                       countbits->children.push_back(mkconst_bits({RTLIL::Sx}, false));
+                                       countbits->children.push_back(mkconst_bits({RTLIL::Sz}, false));
+                                       newNode = new AstNode(AST_GT, countbits, mkconst_int(0, false));
+                               } else if (str == "\\$onehot") {
+                                       countbits->children.push_back(mkconst_bits({RTLIL::State::S1}, false));
+                                       newNode = new AstNode(AST_EQ, countbits, mkconst_int(1, false));
+                               } else if (str == "\\$onehot0") {
+                                       countbits->children.push_back(mkconst_bits({RTLIL::State::S1}, false));
+                                       newNode = new AstNode(AST_LE, countbits, mkconst_int(1, false));
+                               } else {
+                                       log_abort();
+                               }
+
+                               goto apply_newNode;
+                       }
+
                        if (current_scope.count(str) != 0 && current_scope[str]->type == AST_DPI_FUNCTION)
                        {
                                AstNode *dpi_decl = current_scope[str];