diff --git a/src/runtime.rs b/src/runtime.rs
index f765f5f..8308249 100644
--- a/src/runtime.rs
+++ b/src/runtime.rs
@@ -270,15 +270,7 @@ impl RunState {
         match trap_vect {
             // getc
             0x20 => {
-                if stdin().is_terminal() {
-                    let cons = Term::stdout();
-                    let c = cons.read_char().unwrap();
-                    *self.reg(0) = c as u16;
-                } else {
-                    let mut buf = [0; 1];
-                    stdin().read_exact(&mut buf).unwrap();
-                    *self.reg(0) = buf[0] as u16;
-                }
+                *self.reg(0) = read_input() as u16;
             }
             // out
             0x21 => {
@@ -305,19 +297,10 @@ impl RunState {
             }
             // in
             0x23 => {
-                if stdin().is_terminal() {
-                    let mut cons = Term::stdout();
-                    let c = cons.read_char().unwrap();
-                    *self.reg(0) = c as u16;
-                    write!(cons, "{c}").unwrap();
-                    cons.flush().unwrap();
-                } else {
-                    let mut buf = [0; 1];
-                    stdin().read_exact(&mut buf).unwrap();
-                    *self.reg(0) = buf[0] as u16;
-                    print!("{}", buf[0] as char);
-                    stdout().flush().unwrap();
-                }
+                let ch = read_input();
+                *self.reg(0) = ch as u16;
+                print!("{}", ch);
+                stdout().flush().unwrap();
             }
             // putsp
             0x24 => {
@@ -348,3 +331,16 @@ impl RunState {
         }
     }
 }
+
+// Read one byte from stdin or unbuffered terminal
+fn read_input() -> u8 {
+    if stdin().is_terminal() {
+        let cons = Term::stdout();
+        let ch = cons.read_char().unwrap();
+        ch as u8
+    } else {
+        let mut buf = [0; 1];
+        stdin().read_exact(&mut buf).unwrap();
+        buf[0]
+    }
+}