commit - 0867526a43a25c34561967b854d40ce32ab6d174
commit + 0a7f71f87659d462e65e5bd93676f449a510572d
blob - 57d0136c7ccfbf290ae6c5a25dbe8272db144dbb
blob + 5eb4797855ab2813d2ab84f03f306b91fc948005
--- src/chip8.rs
+++ src/chip8.rs
@@ -45,8 +45,9 @@ impl Chip8 {
 
     /// Execute a given instruction.
     pub fn execute(&mut self, instruction: u16) -> Result<(), String> {
+        let nnn = instruction & 0x0FFF;
         match instruction & 0xF000 {
-            0x0 => match instruction & 0x0FFF {
+            0x0 => match nnn {
                 // CLS
                 0x0E0 => {
                     self.video_driver.clear();
@@ -66,8 +67,13 @@ impl Chip8 {
             },
             // JP
             0x1 => {
-                self.pc = instruction & 0x0FFF;
+                self.pc = nnn;
             },
+            // CALL
+            0x2 => {
+                self.stack.push(self.pc + 1);
+                self.pc = nnn;
+            },
             _ => {
                 return Err(format!("{:#06x}: not an instruction", instruction));
             }