feat: initial registers support

src/cpu.rs

+const RAM_SIZE: usize = 8192;
+
 pub struct Cpu {
     pc: u16,
     sp: u16,
@@ -9,9 +11,40 @@ pub struct Cpu {
     reg_f: u8,
     reg_h: u8,
     reg_l: u8,
+    ram: [u8; RAM_SIZE],
 }
 
 impl Cpu {
+    pub fn new() -> Cpu {
+        Cpu {
+            pc: 0x0,
+            sp: 0x0,
+            reg_a: 0x0,
+            reg_b: 0x0,
+            reg_c: 0x0,
+            reg_d: 0x0,
+            reg_e: 0x0,
+            reg_f: 0x0,
+            reg_h: 0x0,
+            reg_l: 0x0,
+            ram: [0u8; RAM_SIZE],
+        }
+    }
+
+    pub fn clock(&mut self) {
+        // fetches the current instruction and increments
+        // the PC (program counter) accordingly
+        let instruction = self.ram[self.pc as usize];
+        self.pc += 1;
+
+        let opcode = instruction & 0xf000;
+        let address = instruction & 0x0fff;
+        let x = ((instruction & 0x0f00) >> 8) as usize;
+        let y = ((instruction & 0x00f0) >> 4) as usize;
+        let nibble = (instruction & 0x000f) as u8;
+        let byte = (instruction & 0x00ff) as u8;
+    }
+
     #[inline(always)]
     fn reg_af(&self) -> u16 {
         (self.reg_a as u16) << 8 | self.reg_f as u16