feat: call prototype

src/cpu.rs

@@ -221,7 +221,7 @@ pub const INSTRUCTIONS: [(fn(&mut Cpu), u8, &'static str); 256] = [
     (nop, 4, "NOP"),
     (nop, 4, "NOP"),
     (nop, 4, "NOP"),
-    (nop, 4, "NOP"),
+    (call_u16, 24, "CALL u16"),
     (nop, 4, "NOP"),
     (nop, 4, "NOP"),
     // 0xd opcodes
@@ -780,6 +780,12 @@ fn xor_a_a(cpu: &mut Cpu) {
     cpu.set_carry(false);
 }
 
+fn call_u16(cpu: &mut Cpu) {
+    // @todo push stack and set the current PC
+    // to be able to jump
+    cpu.sp += 1;
+}
+
 fn ld_mff00u8_a(cpu: &mut Cpu) {
     let byte = cpu.read_u8();
     cpu.mmu.write(0xff0c + byte as u16, cpu.a);