fix(verilog): keep simtime monotonic in readdata

.github/workflows/ci.yml

@@ -115,6 +115,12 @@ jobs:
       - name: Install Icarus Verilog
         run: sudo apt-get update && sudo apt-get install -y iverilog
 
+      - name: Run Verilog read tests
+        run: |
+          mkdir -p "$RUNNER_TEMP/verilog/in1"
+          iverilog -g2012 -I. -o "$RUNNER_TEMP/verilog/test_read_simtime" tests/verilog/test_read_simtime.v
+          cd "$RUNNER_TEMP/verilog" && vvp test_read_simtime
+
       - name: Run Verilog interop tests
         run: julia --color=yes tests/julia/test_verilog_interop.jl
 

concore.v

@@ -126,6 +126,7 @@ module concore;
     input [`CONCORE_MAXLEN*8-1:0] name;
     input [`CONCORE_MAXLEN*8-1:0] initstr;
     reg datavalid;
+    real readtime;
     reg [(`CONCORE_MAXLEN+`INPATHLEN)*8-1:0] fname; //room for 6 extra chars
     reg [7:0] asciiport;
     integer i;
@@ -189,13 +190,16 @@ module concore;
        $fclose(fin);
      end
     //parse
-    literal_eval(datavalid,simtime);
+    literal_eval(datavalid,readtime);
     if (datavalid == 0)
       begin
         retrycount = retrycount + 1;
       end
     //time
    end //datavalid
+    // keep simtime monotonic like the other bindings, an older file or the
+    // init string used for a missing file must not move it back
+    if (readtime > simtime) simtime = readtime;
     end
   endtask
 

concoredocker.v

@@ -126,6 +126,7 @@ module concore;
     input [`CONCORE_MAXLEN*8-1:0] name;
     input [`CONCORE_MAXLEN*8-1:0] initstr;
     reg datavalid;
+    real readtime;
     reg [(`CONCORE_MAXLEN+`INPATHLEN)*8-1:0] fname; //room for 6 extra chars
     reg [7:0] asciiport;
     integer i;
@@ -189,13 +190,16 @@ module concore;
        $fclose(fin);
      end
     //parse
-    literal_eval(datavalid,simtime);
+    literal_eval(datavalid,readtime);
     if (datavalid == 0)
       begin
         retrycount = retrycount + 1;
       end
     //time
    end //datavalid
+    // keep simtime monotonic like the other bindings, an older file or the
+    // init string used for a missing file must not move it back
+    if (readtime > simtime) simtime = readtime;
     end
   endtask
 

tests/protocol_fixtures/cross_runtime_matrix.phase2.json

@@ -268,9 +268,9 @@
           "note": "Audit planned in phase 2."
         },
         "verilog": {
-          "status": "not_audited",
+          "status": "observed_pass",
           "classification": "implementation_defined",
-          "note": "May require binding-specific interpretation."
+          "note": "readdata() falls back to the init string, so data and simtime match the fixture. concore.v has no success flag to return, so the ok=False part has no equivalent. Checked by tests/verilog/test_read_simtime.v."
         }
       }
     },
@@ -304,9 +304,9 @@
           "note": "Audit planned in phase 2."
         },
         "verilog": {
-          "status": "not_audited",
+          "status": "observed_pass",
           "classification": "implementation_defined",
-          "note": "May require binding-specific interpretation."
+          "note": "readdata() only moves simtime forward, an older file timestamp leaves it unchanged. Checked by tests/verilog/test_read_simtime.v."
         }
       }
     }

tests/test_protocol_conformance_phase2.py

@@ -93,3 +93,11 @@ def test_phase2_matrix_cpp_status_is_recorded_for_each_case():
             assert cpp_result["status"] == "observed_fail"
         else:
             assert cpp_result["status"] == "observed_pass"
+
+
+# concore.v only has the file based read path, so the read_file cases are the
+# ones that apply to it. tests/verilog/test_read_simtime.v checks both in CI.
+def test_phase2_matrix_verilog_read_file_cases_pass():
+    for row in _phase2_matrix()["cases"]:
+        if row["target"] == "read_file":
+            assert row["runtime_results"]["verilog"]["status"] == "observed_pass"

tests/verilog/test_read_simtime.v

@@ -0,0 +1,29 @@
+`include "concore.v"
+
+// read_file cases from tests/protocol_fixtures/python_phase1_cases.json
+// run from a directory that has an empty in1/ folder
+module test_read_simtime;
+reg [8*10-1:0] missing_init = "[0.0, 5.0]";
+reg [8*10-1:0] ym_init = "[0.0, 0.0]";
+integer f;
+
+initial begin
+  // read_file/missing_file_returns_default_and_false
+  concore.simtime = 4;
+  concore.readdata(1, "missing", missing_init);
+  if (concore.simtime != 4) $fatal(1, "missing file: simtime is %f, expected 4", concore.simtime);
+  if (concore.data[0] != 5.0) $fatal(1, "missing file: data[0] is %f, expected 5.0", concore.data[0]);
+
+  // read_file/older_timestamp_does_not_decrease_simtime
+  f = $fopen("in1/ym", "w");
+  $fwrite(f, "[7.0, 3.14]");
+  $fclose(f);
+  concore.simtime = 10;
+  concore.readdata(1, "ym", ym_init);
+  if (concore.simtime != 10) $fatal(1, "older timestamp: simtime is %f, expected 10", concore.simtime);
+  if (concore.data[0] != 3.14) $fatal(1, "older timestamp: data[0] is %f, expected 3.14", concore.data[0]);
+
+  $display("read simtime tests passed");
+  $finish;
+end
+endmodule