trap: OUT

src/vm/instruction.rs

@@ -289,7 +289,7 @@ fn op_trap(vm: &mut VM, instr: u16) {
     let trap_vector = instr & 0xff;
     match trap_vector {
         0x20 => trap_getc(vm),
-        0x21 => todo!("OUT"),
+        0x21 => trap_out(vm),
         0x22 => trap_puts(vm),
         0x23 => todo!("IN"),
         0x24 => todo!("PUTSP"),
@@ -315,3 +315,11 @@ fn trap_getc(vm: &mut VM) {
     while vm.mem.get_mem(0xFE00) & (1 << 15) == 0 {}
     vm.registers.r0 = vm.mem.get_mem(0xFE02) & 0xFF;
 }
+
+fn trap_out(vm: &mut VM) {
+    let val = char::from_u32((vm.registers.r0 & 0xFF).into());
+    match val {
+        Some(c) => print!("{}", c),
+        None => {}
+    }
+}