[cpu] Implement rand instruction.rs

src/device/device.rs

@@ -4,6 +4,7 @@ use std::sync::{Arc, Mutex, RwLock};
 use std::thread;
 use std::thread::{JoinHandle, sleep};
 use std::time::Duration;
+use rand::random;
 use crate::device::instruction::Instruction;
 use crate::device::timer::Timer;
 
@@ -117,7 +118,9 @@ impl Device {
             Instruction::ConditionalEqRegisterSkipNext(_, _) => {}
             Instruction::ConditionalInEqRegisterSkipNext(_, _) => {}
             Instruction::JumpWithOffset(_, _) => {}
-            Instruction::RandomOr(_, _) => {}
+            Instruction::RandomAnd(dest, n) => {
+                self.registers.v[dest] = random::<u8>() & n;
+            }
             Instruction::SkipIfKeyPressed(_) => {}
             Instruction::SkipIfKeyNotPressed(_) => {}
             Instruction::Set(x, y) => {

src/device/instruction.rs

@@ -29,7 +29,7 @@ pub enum Instruction {
     /// B(X+N)NN - Jump to address with offset. Either v0 or specified register 
     JumpWithOffset(usize, u16),
     /// CXNN - AND a random number with NN and place in register
-    RandomOr(usize, u16),
+    RandomAnd(usize, u8),
     /// DXYN - Draw pixels at xy pointed by register for n bytes long
     Draw(usize, usize, u8),
 
@@ -123,7 +123,7 @@ impl Instruction {
             0xC => {
                 let register_x = (instruction & 0xf00) >> 8;
                 let mask = instruction & 0xff;
-                Instruction::RandomOr(register_x as usize, mask)
+                Instruction::RandomAnd(register_x as usize, mask as u8)
             }
             0xD => {
                 let x = (instruction & 0xf00) >> 8;
@@ -303,7 +303,7 @@ mod tests {
     fn test_random_and() {
         let instruction_bytes = 0xcabd_u16.to_be_bytes();
         let ins = Instruction::decode_instruction(&instruction_bytes);
-        assert_eq!(ins, RandomOr(0xa, 0xbd));
+        assert_eq!(ins, RandomAnd(0xa, 0xbd));
     }