address review comments

Signed-off-by: Alessandro Comodi <[email protected]>

Author: acomodi

libs/libarchfpga/src/physical_types.h

@@ -1764,6 +1764,21 @@ struct t_arch {
     t_clock_arch* clocks = nullptr;
 
     // Constants
+    // VCC and GND cells are special virtual cells that are
+    // used to handle the constant network of the device.
+    //
+    // Similarly, the constant nets are defined to identify
+    // the generic name for the constant network.
+    //
+    // Given that usually, the constants have a dedicated network in
+    // real FPGAs, this information becomes relevant to identify which
+    // nets from the circuit netlist are belonging to the constant network,
+    // and assigned to it accordingly.
+    //
+    // NOTE: At the moment, the constant cells and nets are primarly used
+    // for the interchange netlist format, to determine which are the constants
+    // net names and which virtual cell is responsible to generate them.
+    // The information is present in the device database.
     std::string gnd_cell;
     std::string vcc_cell;
 

vpr/src/base/read_circuit.cpp

@@ -38,7 +38,7 @@ AtomNetlist read_and_process_circuit(e_circuit_format circuit_format, t_vpr_setu
     if (circuit_format == e_circuit_format::AUTO) {
         auto name_ext = vtr::split_ext(circuit_file);
 
-        VTR_LOG("%s\n", circuit_file);
+        VTR_LOGV(verbosity, "Circuit file: %s\n", circuit_file);
         if (name_ext[1] == ".blif") {
             circuit_format = e_circuit_format::BLIF;
         } else if (name_ext[1] == ".eblif") {
@@ -62,7 +62,9 @@ AtomNetlist read_and_process_circuit(e_circuit_format circuit_format, t_vpr_setu
                 netlist = read_interchange_netlist(circuit_file, arch);
                 break;
             default:
-                VTR_ASSERT(false);
+                VPR_FATAL_ERROR(VPR_ERROR_ATOM_NETLIST,
+                                "Unable to identify circuit file format for '%s'. Expect [blif|eblif|fpga-interchange]!\n",
+                                circuit_file);
                 break;
         }
     }

vpr/src/util/vpr_error.h

@@ -9,17 +9,22 @@
 
 enum e_vpr_error {
     VPR_ERROR_UNKNOWN = 0,
+
+    // Flow errors
     VPR_ERROR_ARCH,
     VPR_ERROR_PACK,
     VPR_ERROR_PLACE,
     VPR_ERROR_ROUTE,
     VPR_ERROR_TIMING,
     VPR_ERROR_POWER,
     VPR_ERROR_SDC,
-    VPR_ERROR_NET_F,
-    VPR_ERROR_PLACE_F,
-    VPR_ERROR_BLIF_F,
-    VPR_ERROR_IC_NETLIST_F,
+
+    // File parsing errors
+    VPR_ERROR_NET_F,        // Error while parsing the packed netlist file
+    VPR_ERROR_PLACE_F,      // Error while parsning the placement file
+    VPR_ERROR_BLIF_F,       // Error while parsing the blif file
+    VPR_ERROR_IC_NETLIST_F, // Error while parsing the interchange netlist file
+
     VPR_ERROR_IMPL_NETLIST_WRITER,
     VPR_ERROR_NETLIST,
     VPR_ERROR_ATOM_NETLIST,