diff --git a/src/grammar/Visitor.hpp b/src/grammar/Visitor.hpp
index 7550126..0f946a4 100644
--- a/src/grammar/Visitor.hpp
+++ b/src/grammar/Visitor.hpp
@@ -71,6 +71,7 @@ class Visitor
 public:
     Environment env;
     std::vector<std::string> include_paths;
+    std::string builtins_path;
 
     ScopeStack scopes;
     std::stack<fs::path> files;
@@ -82,18 +83,38 @@ class Visitor
             const std::string &target_arch,
             const std::string &target_cpu,
             const std::string &target_features,
+            const std::string &builtins_path_,
             const std::vector<std::string> &include_paths_ = {}) : env("output", target_os, target_arch, target_cpu, target_features),
                                                                    include_paths(include_paths_),
+                                                                   builtins_path(builtins_path_),
                                                                    scopes(this->env)
     {
-        this->include_paths.push_back(Environment::get_std_directory().u8string());
+        auto std_directory = Environment::get_std_directory();
+
+        if (this->builtins_path.empty())
+        {
+            this->builtins_path = (std_directory / "builtins").u8string();
+        }
+
+        this->include_paths.push_back(std_directory.u8string());
+    }
+
+    void load_builtins()
+    {
+        for (const auto &p : fs::recursive_directory_iterator(this->builtins_path, fs::directory_options::follow_directory_symlink | fs::directory_options::skip_permission_denied))
+        {
+            if (!p.is_directory())
+            {
+                this->from_file(p.path());
+            }
+        }
     }
 
     void from_file(std::string path)
     {
         if (!this->files.empty())
         {
-            if (Helpers::starts_with(path, "./"))
+            if (Helpers::starts_with(path, "./") || Helpers::starts_with(path, "../"))
             {
                 auto from = this->files.top();
                 path = from.replace_filename(path).u8string();
@@ -143,7 +164,7 @@ class Visitor
         std::ifstream stream;
         stream.open(fullpath);
 
-        files.push(fullpath);
+        this->files.push(fullpath);
 
         auto input = new ANTLRInputStream(stream);
         auto lexer = new SandLexer(input);
diff --git a/src/main.cpp b/src/main.cpp
index 70f7b67..b65fb57 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -108,6 +108,8 @@ struct Options
     std::string output_file = OUTPUT_FILENAME;
     std::vector<std::string> include_paths;
 
+    std::string builtins_path = "";
+
     std::string os = CURRENT_OS;
     std::string arch = CURRENT_ARCH;
     std::string mode = CURRENT_MODE;
@@ -157,12 +159,13 @@ bool compile(const Options &options, Sand::Debugger &debug)
     llvm::InitializeAllAsmParsers();
     llvm::InitializeAllAsmPrinters();
 
-    Sand::Visitor visitor(options.os, options.arch, options.cpu, options.features, options.include_paths);
+    Sand::Visitor visitor(options.os, options.arch, options.cpu, options.features, options.builtins_path, options.include_paths);
 
     debug.start_timer("bytecode");
 
     try
     {
+        visitor.load_builtins();
         visitor.from_file(options.entry_file);
     }
     catch (Sand::CompilationException &e)
@@ -254,6 +257,7 @@ int main(int argc, char **argv)
 
     build->add_option("-O", options.optimization_level, "Optimization level", true);
     build->add_option("-I", options.include_paths, "Include paths", true);
+    build->add_option("-B,--builtins", options.builtins_path, "Builtins path", true);
 
     build->add_option("--arch", options.arch, "Target architecture", true);
     build->add_option("--os", options.os, "Target operating system", true);
@@ -282,8 +286,9 @@ int main(int argc, char **argv)
     CLI::App *run = app.add_subcommand("run", "Run sources");
     run->add_option("ENTRY", options.entry_file, "Entry file")->required()->check(CLI::ExistingFile);
 
-    run->add_option("-O", options.optimization_level, "Optimization level");
-    run->add_option("-I", options.include_paths, "Include paths");
+    run->add_option("-O", options.optimization_level, "Optimization level", true);
+    run->add_option("-I", options.include_paths, "Include paths", true);
+    run->add_option("-B,--builtins", options.builtins_path, "Builtins path", true);
 
     run->add_option("--arch", options.arch, "Target architecture", true);
     run->add_option("--os", options.os, "Target operating system", true);
diff --git a/std/linux/crt0.sn b/std/builtins/intrinsics.sn
similarity index 92%
rename from std/linux/crt0.sn
rename to std/builtins/intrinsics.sn
index b15826b..168d874 100644
--- a/std/linux/crt0.sn
+++ b/std/builtins/intrinsics.sn
@@ -1,4 +1,4 @@
-import "./syscalls"
+import "../linux/syscalls"
 
 #[target_os = "linux"]
 #[target_arch = "x86_64"]
diff --git a/std/windows/chkstk.sn b/std/builtins/x86_64.sn
similarity index 95%
rename from std/windows/chkstk.sn
rename to std/builtins/x86_64.sn
index 0e08c3b..acef09d 100644
--- a/std/windows/chkstk.sn
+++ b/std/builtins/x86_64.sn
@@ -1,3 +1,5 @@
+let _fltused: i32 = 0;
+
 #[target_os = "windows"]
 #[target_arch = "x86_64"]
 fn __chkstk() {