mul

test/init1.rs

@@ -51,23 +51,64 @@ struct Stderr;
 impl core::fmt::Write for Stderr {
     fn write_str(&mut self, s: &str) -> core::fmt::Result {
         let ret = write(2, s.as_bytes());
-        if ret < 0 { Err(core::fmt::Error) } else { Ok(()) }
+        if ret < 0 {
+            Err(core::fmt::Error)
+        } else {
+            Ok(())
+        }
     }
 }
 
+macro_rules! eprintln {
+    ($($tt:tt)*) => {
+        writeln!(Stderr, $($tt)*).unwrap();
+    };
+}
+macro_rules! eprint {
+    ($($tt:tt)*) => {
+        write!(Stderr, $($tt)*).unwrap();
+    };
+}
+
 #[panic_handler]
 fn handle(info: &core::panic::PanicInfo<'_>) -> ! {
     let _ = writeln!(Stderr, "panicked: {}", info.message());
     unsafe { core::arch::asm!("unimp", options(noreturn)) }
 }
 
-#[no_mangle]
-fn _start() {
-    write(1, b"enter a number: ");
-    let mut buf = [0; 10];
-    let len = read(0, &mut buf);
-    let buf = &buf[..(len as usize)];
-    let n = str::from_utf8(buf).unwrap().trim().parse::<i32>().unwrap();
+fn input() -> u64 {
+    eprint!("enter a number: ");
 
-    exit(n);
+    loop {
+        let mut buf = [0; 10];
+        let len = read(0, &mut buf);
+        let buf = &buf[..(len as usize)];
+        let n = str::from_utf8(buf).unwrap().trim();
+        match n.parse::<u64>() {
+            Ok(v) => return v,
+            Err(_) => {
+                eprint!("not a valid number, try again: ");
+            }
+        }
+    }
+}
+
+
+#[no_mangle]
+fn _start() -> ! {
+    let random_number = 45;
+
+    loop {
+        let n = input();
+        if n == random_number {
+            eprintln!("correct!");
+            break;
+        } else if n < random_number {
+            eprintln!("random number is greater");
+        } else {
+            eprintln!("random number is smaller");
+        }
+    }
+
+    exit(0);
 }