diff --git a/kernel/register.cc b/kernel/register.cc
index fe3495dad..99225ba51 100644
--- a/kernel/register.cc
+++ b/kernel/register.cc
@@ -757,6 +757,7 @@ struct SimHelper {
 	}
 	string title;
 	string ports;
+	string source;
 	string desc;
 	string code;
 	string ver;
@@ -901,7 +902,8 @@ struct HelpPass : public Pass {
 		// source code
 		fprintf(f, "Simulation model (Verilog)\n");
 		fprintf(f, "--------------------------\n\n");
-		fprintf(f, ".. code:: verilog\n\n");
+		fprintf(f, ".. code-block:: verilog\n");
+		fprintf(f, "   :caption: %s\n\n", cell.source.c_str());
 		std::stringstream ss;
 		ss << cell.code;
 		for (std::string line; std::getline(ss, line, '\n');) {
diff --git a/techlibs/common/cellhelp.py b/techlibs/common/cellhelp.py
index 312446ad4..1d55d17f5 100644
--- a/techlibs/common/cellhelp.py
+++ b/techlibs/common/cellhelp.py
@@ -3,11 +3,13 @@
 from __future__ import annotations
 import fileinput
 import json
+from pathlib import Path
 
 class SimHelper:
     name: str = ""
     title: str = ""
     ports: str = ""
+    source: str = ""
     desc: list[str]
     code: list[str]
     ver: str = "1"
@@ -16,14 +18,19 @@ class SimHelper:
         self.desc = []
     
     def __str__(self) -> str:
+        printed_fields = [
+            "name", "title", "ports", "source", "desc", "code", "ver",
+        ]
+        # generate C++ struct
         val = "tempCell = {\n"
-        val += f'  {json.dumps(self.name)},\n'
-        val += f'  {json.dumps(self.title)},\n'
-        val += f'  {json.dumps(self.ports)},\n'
-        val += '  ' + json.dumps("\n".join(self.desc)) + ',\n'
-        val += '  ' + json.dumps("\n".join(self.code)) + ',\n'
-        val += f'  {json.dumps(self.ver)},\n'
+        for field in printed_fields:
+            field_val = getattr(self, field)
+            if isinstance(field_val, list):
+                field_val = "\n".join(field_val)
+            val += f'  {json.dumps(field_val)},\n'
         val += "};\n"
+
+        # map name to struct
         val += f'cell_help[{json.dumps(self.name)}] = tempCell;'
         val += "\n"
         val += f'cell_code[{json.dumps(self.name + "+")}] = tempCell;'
@@ -45,6 +52,8 @@ for line in fileinput.input():
         clean_line = line[7:].replace("\\", "").replace(";", "")
         simHelper.name, simHelper.ports = clean_line.split(maxsplit=1)
         simHelper.code = []
+        short_filename = Path(fileinput.filename()).name
+        simHelper.source = f'{short_filename}:{fileinput.filelineno()}'
     elif not line.startswith("endmodule"):
         line = "    " + line
     try: