diff --git a/core/include/nova64_api.h b/core/include/nova64_api.h
new file mode 100644
index 0000000..1c84685
--- /dev/null
+++ b/core/include/nova64_api.h
@@ -0,0 +1,6 @@
+#ifndef NOVA64_API_H
+#define NOVA64_API_H
+
+void register_nova64_imports(void);
+
+#endif // NOVA64_API_H
diff --git a/core/src/nova64_api.c b/core/src/nova64_api.c
new file mode 100644
index 0000000..95050b2
--- /dev/null
+++ b/core/src/nova64_api.c
@@ -0,0 +1,24 @@
+#include "FreeRTOS.h"
+#include "task.h"
+#include "wasm_export.h"
+#include "projdefs.h"
+
+static void native_yield(wasm_exec_env_t exec_env, uint32_t timeout_ms) {
+  if (timeout_ms == 0) {
+    // Gibt die Rest-Quantenzeit ab, blockiert aber nicht künstlich
+    taskYIELD();
+  } else {
+    // Blockiert den Task für x Millisekunden
+    vTaskDelay(pdMS_TO_TICKS(timeout_ms));
+  }
+}
+
+static NativeSymbol native_symbols[] = {
+    {"yield", (void *)native_yield, "(i)", NULL},
+    // { "flush_framebuffer",  (void*)native_flush_framebuffer, "()",  NULL }
+};
+
+void register_nova64_imports(void) {
+  wasm_runtime_register_natives("nova64", native_symbols,
+                                sizeof(native_symbols) / sizeof(NativeSymbol));
+}
\ No newline at end of file
diff --git a/core/src/wasm_runner.c b/core/src/wasm_runner.c
index 38e4d99..0683460 100644
--- a/core/src/wasm_runner.c
+++ b/core/src/wasm_runner.c
@@ -1,6 +1,7 @@
 #include "wasm_runner.h"
 #include "nova64_fs.h"
 #include "nova64_internal.h"
+#include "nova64_api.h"
 #include "wasm_export.h"
 #include <stdlib.h>
 
@@ -17,6 +18,7 @@ uint32_t stack_size = 8092, heap_size = 8092;
 bool wasm_runner_initialize(void) {
 
   wasm_runtime_init();
+  register_nova64_imports();
   nova64_log("WASM runtime initialized successfully.\n");
 
   const char *module_file = "SYS:/init.wasm";
@@ -44,7 +46,33 @@ bool wasm_runner_initialize(void) {
   wasm_module_inst_t module_inst = wasm_runtime_instantiate(
       module, stack_size, heap_size, error_buf, sizeof(error_buf));
 
-  wasm_exec_env_t exec_env = wasm_runtime_create_exec_env(module_inst, stack_size);
-  
+  wasm_function_inst_t start_func =
+      wasm_runtime_lookup_function(module_inst, "_start");
+
+  if (start_func == NULL) {
+    nova64_log("Failed to find '_start' function in WASM module: %s\n",
+               wasm_runtime_get_exception(module_inst));
+    free(buffer);
+    return false;
+  }
+
+  wasm_exec_env_t exec_env =
+      wasm_runtime_create_exec_env(module_inst, stack_size);
+
+  uint32_t argv[2] = {5, 3}; // Example arguments for the "add" function
+
+  if (wasm_runtime_call_wasm(exec_env, start_func, 2, argv)) {
+    nova64_log("WASM module executed successfully. Sum: %d\n", argv[0]);
+  } else {
+    nova64_log("Failed to execute WASM module: %s\n",
+               wasm_runtime_get_exception(module_inst));
+  }
+
+  wasm_runtime_destroy_exec_env(exec_env);
+  wasm_runtime_deinstantiate(module_inst);
+  wasm_runtime_unload(module);
+  free(buffer);
+  wasm_runtime_destroy();
+
   return true;
 }
diff --git a/simulator/sd/slot0/init.wasm b/simulator/sd/slot0/init.wasm
index 3ef499b..dd9f70d 100644
Binary files a/simulator/sd/slot0/init.wasm and b/simulator/sd/slot0/init.wasm differ
diff --git a/software/build.bat b/software/build.bat
index 9c4868b..19ae4d5 100644
--- a/software/build.bat
+++ b/software/build.bat
@@ -1 +1,4 @@
-tinygo build -o ../simulator/sd/slot0/init.wasm -target wasm-unknown init.go
\ No newline at end of file
+@REM tinygo build -o ../simulator/sd/slot0/init.wasm -target wasm-unknown init.go
+
+@REM zig build-exe init.zig -target wasm32-freestanding -fno-entry -O ReleaseSmall -femit-bin=../simulator/sd/slot0/init.wasm
+zig build-exe init.zig -target wasm32-freestanding -O ReleaseSmall -femit-bin=../simulator/sd/slot0/init.wasm
\ No newline at end of file
diff --git a/software/init.go b/software/init.go
index 39166ef..a1dbd3c 100644
--- a/software/init.go
+++ b/software/init.go
@@ -2,7 +2,9 @@ package main
 
 // Declare a main function, this is the entrypoint into our go module
 // That will be run. In our example, we won't need this
-func main() {}
+func main() {
+	_ = add(1, 2)
+}
 
 // This exports an add function.
 // It takes in two 32-bit integer values
diff --git a/software/init.zig b/software/init.zig
new file mode 100644
index 0000000..4b81eca
--- /dev/null
+++ b/software/init.zig
@@ -0,0 +1,12 @@
+extern "nova64" fn yield(timeout_ms: u32) void;
+
+pub fn main() void {
+    _ = add(1, 2);
+    while (true) {
+        yield(16); // Yield for 1 second
+    }
+}
+
+export fn add(a: i32, b: i32) i32 {
+    return a + b;
+}