From 3876eba0504bfe13e9522d48130bfafc7d8b1e8d Mon Sep 17 00:00:00 2001
From: Jason Hilder <jhilder95@gmail.com>
Date: Wed, 27 May 2026 07:16:39 +0200
Subject: [PATCH] added the last set of instructions.

---
 src/machine/cpu.odin | 78 +++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 70 insertions(+), 8 deletions(-)

diff --git a/src/machine/cpu.odin b/src/machine/cpu.odin
index 87d89bd..a024317 100644
--- a/src/machine/cpu.odin
+++ b/src/machine/cpu.odin
@@ -1,6 +1,7 @@
 package machine
 
 import "core:log"
+import "core:math/rand"
 import "base:intrinsics"
 
 // CPU.odin -> instructions, fetch, decode, execute, run loop
@@ -51,10 +52,22 @@ cycle :: proc(s: ^System) {
 		case 0x9: op_skip_reg_condition(s, vx_idx, vy_idx, false)
 		case 0xA: op_set(s, nnn)
 		case 0xB: op_jp_offset(s, nnn)
+		case 0xC: op_rnd(s, vx_idx, kk)
 		case 0xD: op_draw(s, vx_idx, vy_idx, last_nibble)
+		case 0xE: {
+			switch kk {
+				case 0x9E: op_skip_on_keypress(s, vx_idx)
+				case 0xA1: op_skip_on_nokeypress(s, vx_idx)
+			}
+		}
 		case 0xF: {
 			switch kk {
+				case 0x07: op_ld_dt(s, vx_idx)
+				case 0x0A: op_get_key(s, vx_idx)
+				case 0x15: op_set_dt(s, vx_idx)
+				case 0x18: op_set_st(s, vx_idx)
 				case 0x1E: op_add_i(s, vx_idx)
+				case 0x29: op_set_i(s, vx_idx)
 				case 0x33: op_split_i(s, vx_idx)
 				case 0x55: op_mem_set(s, vx_idx)
 				case 0x65: op_mem_get(s, vx_idx)
@@ -194,7 +207,11 @@ op_jp_offset :: proc(s: ^System, nnn: u16) {
 	s.pc += u16(s.v[0])
 }
 
-// Cxkk - RND Vx, byte : @TODO!
+// Cxkk - RND Vx, byte
+op_rnd :: proc(s: ^System, vx_idx: u16, kk: u8) {
+	rand_int := u8(rand.int_max(256))
+	s.v[vx_idx] = (rand_int & kk)
+}
 
 // Dxyn - DRW Vx, Vy, nibble
 op_draw :: proc(s: ^System, vx_idx, vy_idx, n: u16) {
@@ -233,12 +250,54 @@ op_draw :: proc(s: ^System, vx_idx, vy_idx, n: u16) {
 	}
 }
 
-// Ex9E - SKP Vx : @TODO
-// ExA1 - SKNP Vx : @TODO
-// Fx07 - LD Vx, DT : @TODO
-// Fx0A - LD Vx, K : @TODO
-// Fx15 - LD DT, Vx : @TODO
-// Fx18 - LD ST, Vx : @TODO
+// Ex9E - SKP Vx
+op_skip_on_keypress :: proc(s: ^System, vx_idx: u16) {
+	reg_value := s.v[vx_idx]
+	if s.keypad[reg_value] {
+		s.pc += 2
+	}
+}
+
+// ExA1 - SKNP Vx
+op_skip_on_nokeypress :: proc(s: ^System, vx_idx: u16) {
+	reg_value := s.v[vx_idx]
+	if !s.keypad[reg_value] {
+		s.pc += 2
+	}
+}
+
+// Fx07 - LD Vx, DT
+op_ld_dt :: proc(s: ^System, vx_idx: u16) {
+	s.v[vx_idx] = s.delay_timer
+}
+
+// Fx0A - LD Vx, K
+op_get_key :: proc(s: ^System, vx_idx: u16) {
+	for val, kp_idx in s.keypad {
+		if val == true {
+			s.v[vx_idx] = u8(kp_idx)
+
+			// return here so it does not decrement
+			return
+		}
+	}
+
+	// if loop does not return decrement go into loop
+	s.pc -= 2
+}
+
+
+// Fx15 - LD DT, Vx
+op_set_dt :: proc(s: ^System, vx_idx: u16) {
+	// set delay timer to value of x register
+	s.delay_timer = s.v[vx_idx]
+}
+
+// Fx18 - LD ST, Vx
+op_set_st :: proc(s: ^System, vx_idx: u16) {
+	// set sound timer to value of x register
+	s.sound_timer = s.v[vx_idx]
+}
 
 // Fx1E - ADD I, Vx
 op_add_i :: proc(s: ^System, vx_idx: u16) {
@@ -246,7 +305,10 @@ op_add_i :: proc(s: ^System, vx_idx: u16) {
 	s.v[0xF] = u8(1) if s.i > 0xFFF else u8(0)
 }
 
-// Fx29 - LD F, Vx : @TODO
+// Fx29 - LD F, Vx
+op_set_i :: proc(s: ^System, vx_idx: u16) {
+	s.i = u16(s.v[vx_idx]) * 5
+}
 
 // Fx33 - LD B, Vx
 op_split_i :: proc(s: ^System, vx_idx: u16) {