Add registers in rust

bench/programs_rust/hello-rust/src/main.rs

@@ -0,0 +1,26 @@
+#![no_std]
+#![no_main]
+
+use core::arch::asm;
+
+use fpga_lib::{panic_handler, register::X31};
+
+panic_handler! {}
+
+#[unsafe(no_mangle)]
+pub extern "C" fn _start() -> ! {
+    X31::write_const::<0xdead1ffffffff>();
+    let test = X31::read() + 10;
+    unsafe {
+        asm!(
+            "add x31, x0, x0",
+            "add x31, x0, {}", in(reg) test
+        );
+
+        const VGA: *mut u8 = 0x80000000 as *mut u8;
+        VGA.write_volatile(255);
+        // VGA.add(1).write_volatile(255);
+    }
+
+    loop {}
+}