Add execution to VM via file, starting to iron out bugs

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/vm/tick.rs

@@ -1,4 +1,5 @@
 use crate::vm::{error::*, flags::Flags, inst::*, reg::*, vm::*};
+use std::io::stdin;
 
 impl Vm {
     pub fn tick(&mut self) -> Result<()> {
@@ -120,6 +121,12 @@ impl Vm {
             _ => panic!("unknown instruction opcode: 0x{:04x}", op),
         }
 
+        println!("op: {:04x} {}", op, inst_name(op).unwrap());
+        println!("ip: {:05x}", self.ip());
+        println!("next_ip: {:05x}", next_ip);
+        let mut _line = String::new();
+        stdin().read_line(&mut _line).unwrap();
+    
         self.set_reg(IP, next_ip);
 
         Ok(())