diff --git a/components/rustlib/src/lib.rs b/components/rustlib/src/lib.rs
index ad14f10..a2f83e6 100644
--- a/components/rustlib/src/lib.rs
+++ b/components/rustlib/src/lib.rs
@@ -1,8 +1,11 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
+#![feature(asm)]
+
 #[cfg(not(feature = "std"))]
 use core::panic::PanicInfo;
 
+
 /// Create aliases for FFI types for esp32c3, which doesn't have std.
 #[cfg(not(feature = "std"))]
 mod ffi {
@@ -31,6 +34,19 @@ pub extern "C" fn add_in_rust(x: i32, y: i32) -> i32 {
     x + y
 }
 
+#[no_mangle]
+pub extern "C" fn add_in_rust_inline_asm(mut x: i32, y: i32) -> i32 {
+    unsafe {
+        sys::validate_param_in_c(0, x);
+        sys::validate_param_in_c(1, y);
+    }
+    unsafe {
+        // more detail available: https://doc.rust-lang.org/beta/unstable-book/library-features/asm.html
+        asm!("add {0}, {0}, {1}", inout(reg) x, in(reg) y);
+    }
+    x
+}
+
 #[cfg(not(feature = "std"))]
 #[panic_handler]
 fn panic(_info: &PanicInfo) -> ! {
diff --git a/main/main.c b/main/main.c
index 92e6838..eac3bba 100644
--- a/main/main.c
+++ b/main/main.c
@@ -40,6 +40,11 @@ void app_main(void)
     int sum = add_in_rust(x, y);
     printf("Rust calculated %d + %d = %d\n\n", x, y, sum);
 
+    x = 9;
+    y = 10;
+    sum = add_in_rust_inline_asm(x, y);
+    printf("Rust calculated (using asm!) %d + %d = %d\n\n", x, y, sum);
+
     for (int i = 10; i >= 0; i--) {
         printf("Restarting in %d seconds...\n", i);
         vTaskDelay(1000 / portTICK_PERIOD_MS);