Implemented $_DFFSR_ expression generator in verilog backend

diff --git a/backends/verilog/verilog_backend.cc b/backends/verilog/verilog_backend.cc
index 66a4978088afbbf511f7ba342faac921c5a09507..b9d5e5ec2134b3c2d6193769942f65c0ecd34b4b 100644 (file)
--- a/backends/verilog/verilog_backend.cc
+++ b/backends/verilog/verilog_backend.cc
@@ -434,6 +434,49 @@ bool dump_cell_expr(FILE *f, std::string indent, RTLIL::Cell *cell)
                return true;
        }
 
+       if (cell->type.substr(0, 8) == "$_DFFSR_")
+       {
+               char pol_c = cell->type[8], pol_s = cell->type[9], pol_r = cell->type[10];
+
+               std::string reg_name = cellname(cell);
+               bool out_is_reg_wire = is_reg_wire(cell->connections["\\Q"], reg_name);
+
+               if (!out_is_reg_wire)
+                       fprintf(f, "%s" "reg %s;\n", indent.c_str(), reg_name.c_str());
+
+               dump_attributes(f, indent, cell->attributes);
+               fprintf(f, "%s" "always @(%sedge ", indent.c_str(), pol_c == 'P' ? "pos" : "neg");
+               dump_sigspec(f, cell->connections["\\C"]);
+               fprintf(f, " or %sedge ", pol_s == 'P' ? "pos" : "neg");
+               dump_sigspec(f, cell->connections["\\S"]);
+               fprintf(f, " or %sedge ", pol_r == 'P' ? "pos" : "neg");
+               dump_sigspec(f, cell->connections["\\R"]);
+               fprintf(f, ")\n");
+
+               fprintf(f, "%s" "  if (%s", indent.c_str(), pol_r == 'P' ? "" : "!");
+               dump_sigspec(f, cell->connections["\\R"]);
+               fprintf(f, ")\n");
+               fprintf(f, "%s" "    %s <= 0;\n", indent.c_str(), reg_name.c_str());
+
+               fprintf(f, "%s" "  else if (%s", indent.c_str(), pol_s == 'P' ? "" : "!");
+               dump_sigspec(f, cell->connections["\\S"]);
+               fprintf(f, ")\n");
+               fprintf(f, "%s" "    %s <= 1;\n", indent.c_str(), reg_name.c_str());
+
+               fprintf(f, "%s" "  else\n", indent.c_str());
+               fprintf(f, "%s" "    %s <= ", indent.c_str(), reg_name.c_str());
+               dump_cell_expr_port(f, cell, "D", false);
+               fprintf(f, ";\n");
+
+               if (!out_is_reg_wire) {
+                       fprintf(f, "%s" "assign ", indent.c_str());
+                       dump_sigspec(f, cell->connections["\\Q"]);
+                       fprintf(f, " = %s;\n", reg_name.c_str());
+               }
+
+               return true;
+       }
+
 #define HANDLE_UNIOP(_type, _operator) \
        if (cell->type ==_type) { dump_cell_expr_uniop(f, indent, cell, _operator); return true; }
 #define HANDLE_BINOP(_type, _operator) \
@@ -573,7 +616,7 @@ bool dump_cell_expr(FILE *f, std::string indent, RTLIL::Cell *cell)
                return true;
        }
 
-       // FIXME: $_SR_[PN][PN]_, $_DFFSR_[PN][PN][PN]_, $_DLATCH_[PN]_
+       // FIXME: $_SR_[PN][PN]_, $_DLATCH_[PN]_
        // FIXME: $sr, $dffsr, $dlatch, $memrd, $memwr, $mem, $fsm
 
        return false;