feat: implement fetch, decode, execute loop

src/main.rs

@@ -1,3 +1,18 @@
+use gb::cpu::Cpu as LR35902;
+
 fn main() {
-    println!("Hello World!");
+    let mut game_boy = LR35902::new();
+
+    loop {
+        let pc = game_boy.register_pair(gb::cpu::RegisterPair::PC);
+        let opcode = game_boy.fetch();
+        let instruction = game_boy.decode(opcode);
+
+        println!(
+            "Addr: {:#06x} | Opcode: {:#x} | Instr: {:x?}",
+            pc, opcode, instruction
+        );
+
+        game_boy.execute(instruction);
+    }
 }