diff --git a/include/Util.h b/include/Util.h
index fed441b..2e3d58d 100644
--- a/include/Util.h
+++ b/include/Util.h
@@ -106,4 +106,38 @@ template <class X, class Y> struct is_comparable {
 
 template <class X, class Y> constexpr bool is_comparable_v = is_comparable<X, Y>::value;
 
+// trim from start (in place)
+inline void ltrim(std::string& s) {
+  s.erase(s.begin(), std::find_if(s.begin(), s.end(), [](unsigned char ch) { return !std::isspace(ch); }));
+}
+
+// trim from end (in place)
+inline void rtrim(std::string& s) {
+  s.erase(std::find_if(s.rbegin(), s.rend(), [](unsigned char ch) { return !std::isspace(ch); }).base(), s.end());
+}
+
+// trim from both ends (in place)
+inline void trim(std::string& s) {
+  rtrim(s);
+  ltrim(s);
+}
+
+// trim from start (copying)
+inline std::string ltrim_copy(std::string s) {
+  ltrim(s);
+  return s;
+}
+
+// trim from end (copying)
+inline std::string rtrim_copy(std::string s) {
+  rtrim(s);
+  return s;
+}
+
+// trim from both ends (copying)
+inline std::string trim_copy(std::string s) {
+  trim(s);
+  return s;
+}
+
 #endif
diff --git a/include/VirtualMachine.h b/include/VirtualMachine.h
index db3bd73..45f33af 100644
--- a/include/VirtualMachine.h
+++ b/include/VirtualMachine.h
@@ -11,6 +11,7 @@
 #include <cstdlib>
 #include <functional>
 #include <iostream>
+#include <iterator>
 #include <utility>
 #include <variant>
 
@@ -19,6 +20,10 @@ struct FunctionEntry {
       : _name(std::move(name)), _argument_count(arg_count), _address(adr) {
   }
 
+  FunctionEntry(std::string name, uint8_t arg_count, const std::string& label)
+      : _name(std::move(name)), _argument_count(arg_count), _label(label) {
+  }
+
   auto name() const -> const std::string& {
     return _name;
   }
@@ -28,11 +33,18 @@ struct FunctionEntry {
   auto address() const -> std::size_t {
     return _address;
   }
+  auto label() const -> const std::string& {
+    return _label;
+  }
+  void address(std::size_t adr) {
+    _address = adr;
+  }
 
 private:
   std::string _name;
   uint8_t _argument_count;
   std::size_t _address;
+  std::string _label;
 };
 
 template <class VM> using NativeFunction = std::function<ResultOr<bool>(VM* vm, const std::vector<VMType>&)>;
diff --git a/src/pasm/pasm.cpp b/src/pasm/pasm.cpp
index aaccf8c..7521ed6 100644
--- a/src/pasm/pasm.cpp
+++ b/src/pasm/pasm.cpp
@@ -1,5 +1,214 @@
 #include "VirtualMachine.h"
+#include "Util.h"
+#include <filesystem>
+#include <format>
+#include <ostream>
+#include <fstream>
+#include <vector>
+
+template <typename... Args> void print(std::format_string<Args...> fmt, Args&&... args) {
+  std::print(std::cout, fmt, std::forward<Args>(args)...);
+}
+
+struct PasmOption {
+  std::string output_file;
+};
+
+void fatal() {
+  print("pasm: fatal: no input file specified\n Type pasm -h for help.\n\n");
+}
+
+void usage() {
+  print("Usage: pasm [options...] filename\n");
+  print("       pasm -v\n");
+  print("Options (values in brackets indicate defaults):\n\n");
+  print("    -h            show this text and exit\n");
+  print("    -v            print the pasm version number and exit\n");
+  print("    -o outfile    write output to outfile\n");
+}
+
+void version() {
+  print("pasm version 0.0.1 compiled on ...\n");
+}
+
+void print_usage_and_exit_if(bool condition) {
+  if (condition) {
+    usage();
+    std::exit(0);
+  }
+}
+
+auto options(const std::vector<std::string>& args) -> PasmOption {
+  PasmOption opt;
+  for (std::size_t i = 1; i < args.size(); ++i) {
+    if (args[i] == "-v") {
+      version();
+      std::exit(0);
+    }
+    if (args[i] == "-h") {
+      print_usage_and_exit_if(true);
+    }
+    if (args[i] == "-o") {
+      print_usage_and_exit_if(i + 1 >= args.size());
+      opt.output_file = args[i + 1];
+      i++;
+    }
+  }
+  return opt;
+}
+
+void inc_index_if_whitespace(std::size_t& i, const std::string& str) {
+  if (i >= str.length()) {
+    return;
+  }
+  if (str[i] == ' ' || str[i] == '\t' || str[i] == '\n') {
+    for (; i < str.length(); ++i) {
+      if (str[i] != ' ' && str[i] != '\t' && str[i] != '\n') {
+        break;
+      }
+    }
+  }
+}
+
+void store_value_until_whitespace(std::size_t& i, std::string& value, const std::string& str) {
+  for (; i < str.length(); ++i) {
+    if (str[i] == ' ' || str[i] == '\t' || str[i] == '\n') {
+      break;
+    }
+    value += str[i];
+  }
+}
+
+void extract_value(std::string& value, const std::string& line) {
+  std::size_t i = 0;
+  inc_index_if_whitespace(i, line);
+  store_value_until_whitespace(i, value, line);
+}
+
+void parse_function_entry_item(std::size_t& i, std::string& value, const std::string& entry, std::size_t line_nr) {
+  inc_index_if_whitespace(i, entry);
+  store_value_until_whitespace(i, value, entry);
+  if (value.length() == 0) {
+    std::string trimmed_entry = trim_copy(entry);
+    print("pasm: Missing function entry item in line {}! Content is {}\n", line_nr, trimmed_entry);
+    exit(1);
+  }
+}
+
+auto make_function_entry(const std::string& entry, std::size_t line_nr) -> FunctionEntry {
+  std::string fname;
+  std::string argC;
+  std::string label;
+  std::size_t i = 0;
+
+  parse_function_entry_item(i, fname, entry, line_nr);
+  parse_function_entry_item(i, argC, entry, line_nr);
+  parse_function_entry_item(i, label, entry, line_nr);
+  inc_index_if_whitespace(i, entry);
+  if (i < entry.length()) {
+    print("pasm: parsing error in function section line {}! valid format is: [function name] [argument] [count label] "
+          "not {}\n",
+          line_nr, entry);
+    std::exit(1);
+  }
+  bool is_zero = false;
+  if (argC.length() == 1 && argC[0] == '0') {
+    is_zero = true;
+  }
+  uint8_t arg_count = std::atoi(argC.c_str());
+
+  if (arg_count == 0 && !is_zero) {
+    print("pasm: parsing error in function section in line {}! argument count is not a number: {}\n", line_nr, argC);
+    std::exit(1);
+  }
+
+  return FunctionEntry(fname, arg_count, label);
+}
+
+auto parse_function_entries(std::ifstream& stream, std::size_t& line_nr) -> std::vector<FunctionEntry> {
+  std::string entry;
+  std::vector<FunctionEntry> f_entries;
+  bool valid_block = false;
+  while (!std::getline(stream, entry).eof()) {
+    line_nr++;
+    std::string first_item;
+    extract_value(first_item, entry);
+    if (first_item.length() > 0 && first_item[0] == '#') {
+      // comment
+      continue;
+    }
+    if (first_item == "$end") {
+      valid_block = true;
+      break;
+    }
+    FunctionEntry e = make_function_entry(entry, line_nr);
+    f_entries.push_back(e);
+  }
+  if (!valid_block) {
+    print("pasm: parsing error in function section! function section not closed with $end\n");
+    std::exit(1);
+  }
+  return f_entries;
+}
+
+void check_is_stream_open(std::ifstream& stream, const std::string& file) {
+  if (!stream.is_open()) {
+    if (!std::filesystem::is_regular_file(file)) {
+      print("pasm: fatal: unable to open file `{}' File path doesn't refer to a regular file\n", file);
+    } else {
+      print("pasm: fatal: unable to open file `{}' Possible cause:\n", file);
+      print("       - No read access to the file.\n");
+      print("       - The file is locked by  another process.\n");
+      print("       - A file system error occured.\n");
+      print("       - Unknown error.\n");
+    }
+    std::exit(1);
+  }
+}
+
+void run(const PasmOption& opt, const std::string& file) {
+  std::ifstream stream(file, std::ios::binary);
+  check_is_stream_open(stream, file);
+  std::string line;
+  std::size_t line_nr = 0;
+  std::vector<FunctionEntry> function_entries;
+  while (!std::getline(stream, line).eof()) {
+    line_nr++;
+    std::string header;
+    extract_value(header, line);
+    if (header.length() > 0 && header[0] == '#') {
+      continue;
+    }
+    if (header == "$function_section") {
+      if (function_entries.size() == 0) {
+        function_entries = parse_function_entries(stream, line_nr);
+      } else {
+        print("pasm: fatal: multiple function_section found in line {}!", line_nr);
+        std::exit(0);
+      }
+    }
+    if (header == "$code_section") {
+      // parse_code_section(stream, line_nr);
+    }
+  }
+}
 
 auto main(int argc, char** argv) -> int {
+  if (argc < 2) {
+    fatal();
+    return 1;
+  }
+  std::vector<std::string> args(argv, argv + argc);
+  PasmOption opt;
+  if (argv[1][0] == '-') {
+    opt = options(args);
+  }
+  std::string input_file = *(args.end() - 1);
+  if (!std::filesystem::exists(input_file)) {
+    print("pasm: fatal: unable to open input file `{}' No such file or directory\n", input_file);
+    std::exit(1);
+  }
+
+  run(opt, input_file);
   return 0;
 }
diff --git a/tests/pasm_tests/syntax_failed1.pasm b/tests/pasm_tests/syntax_failed1.pasm
new file mode 100644
index 0000000..d9ac0d0
--- /dev/null
+++ b/tests/pasm_tests/syntax_failed1.pasm
@@ -0,0 +1,4 @@
+$function_section
+  2 foo_label
+$end
+# RESULT:pasm: Missing function entry item in line 2! Content is 2 foo_label
diff --git a/tests/pasm_tests/syntax_failed2.pasm b/tests/pasm_tests/syntax_failed2.pasm
new file mode 100644
index 0000000..eb461c4
--- /dev/null
+++ b/tests/pasm_tests/syntax_failed2.pasm
@@ -0,0 +1,3 @@
+$function_section
+ foo  2 foo_label
+#RESULT:pasm: parsing error in function section! function section not closed with $end
diff --git a/tests/pasm_tests/syntax_failed3.pasm b/tests/pasm_tests/syntax_failed3.pasm
new file mode 100644
index 0000000..047ddef
--- /dev/null
+++ b/tests/pasm_tests/syntax_failed3.pasm
@@ -0,0 +1,4 @@
+$function_section
+ foo a foo_label
+$end
+#RESULT:pasm: parsing error in function section in line 2! argument count is not a number: a
diff --git a/tests/pasm_tests/syntax_test.pasm b/tests/pasm_tests/syntax_test.pasm
new file mode 100644
index 0000000..42427ff
--- /dev/null
+++ b/tests/pasm_tests/syntax_test.pasm
@@ -0,0 +1,4 @@
+$function_section
+  foo 2 foo_label
+$end
+# RESULT:
diff --git a/toolchain/executable_tester.py b/toolchain/executable_tester.py
new file mode 100644
index 0000000..3e9d952
--- /dev/null
+++ b/toolchain/executable_tester.py
@@ -0,0 +1,77 @@
+import subprocess
+import os
+import re
+
+# Pfade anpassen
+PASM_EXECUTABLE = "./pasm"  # Pfad zur ausführbaren Datei
+TEST_DIR = "./tests/pasm_tests"    # Ordner mit den Testdateien
+
+def run_test(input_file):
+    # Input-Datei lesen
+    with open(input_file, "r") as file:
+        lines = file.readlines()
+
+    # Erwartetes Ergebnis auslesen (z. B. # RESULT: [...])
+    expected_result = None
+    for line in lines:
+        match = re.match(r"#[ ]*[Rr][Ee][Ss][Uu][Ll][Tt]:\s*(.*)", line)
+        if match:
+            expected_result = match.group(1).strip()
+            break
+
+    if expected_result is None:
+        print(f"❌ Expected result not definied in {input_file}!")
+        return False
+
+    # `pasm` mit der Input-Datei ausführen
+    try:
+        result = subprocess.run(
+            [PASM_EXECUTABLE, input_file],
+            input="".join(lines),  # Input übergeben
+            text=True,             # Textausgabe aktivieren
+            capture_output=True    # Ausgabe abfangen
+        )
+    except FileNotFoundError:
+        print(f"❌ Executable '{PASM_EXECUTABLE}' not found!")
+        return False
+
+    # Ausgabe überprüfen
+    actual_result = result.stdout.strip()
+    if len(expected_result) > 0 and actual_result == expected_result:
+        print(f"✅ Test {os.path.basename(input_file)} passed!")
+        return True
+    else:
+        if len(expected_result)==0:
+            if result.returncode == 0:
+                print(f"✅ Test {os.path.basename(input_file)} passed!")
+                return True
+        print(f"❌ Test {os.path.basename(input_file)} failed!")
+        print(f"  Expected: {expected_result}")
+        print(f"    Result: {actual_result}")
+        return False
+
+def main():
+    # Alle `.input`-Dateien im Testverzeichnis finden
+    input_files = [f for f in os.listdir(TEST_DIR) if f.endswith(".pasm")]
+
+    if not input_files:
+        print("❌ No input file found!")
+        return
+
+    # Tests ausführen
+    passed = 0
+    failed = 0
+    for input_file in input_files:
+        if run_test(os.path.join(TEST_DIR, input_file)):
+            passed += 1
+        else:
+            failed += 1
+
+    # Zusammenfassung
+    print("\n--- Test conclusion ---")
+    print(f"Passed: {passed}")
+    print(f"Failed: {failed}")
+    print(f"Sum: {len(input_files)}")
+
+if __name__ == "__main__":
+    main()