diff --git a/snes-core/src/utils/addressing.rs b/snes-core/src/utils/addressing.rs
new file mode 100644
index 0000000..ffb4689
--- /dev/null
+++ b/snes-core/src/utils/addressing.rs
@@ -0,0 +1,336 @@
+use crate::bus::Bus;
+/// NOTE: These functions only return the `address` in BUS of where the actual value is stored.
+
+/// OPCODE #const
+pub fn immediate(pc_addr: u32) -> u32 {
+    pc_addr + 1
+}
+
+/// OPCODE addr
+pub fn absolute(bus: &Bus, pc_addr: u32) -> u32 {
+    (pc_addr & 0xFF0000) |
+    (bus.read(pc_addr + 1) as u32) |
+    ((bus.read(pc_addr + 2) as u32) << 8)
+}
+
+/// OPCODE long
+pub fn absolute_long(bus: &Bus, pc_addr: u32) -> u32 {
+    (bus.read(pc_addr + 1) as u32) |
+    ((bus.read(pc_addr + 2) as u32) << 8) |
+    ((bus.read(pc_addr + 3) as u32) << 16)
+}
+
+/// OPCODE dp
+pub fn direct_page(bus: &Bus, pc_addr: u32, direct_page_register: u16) -> u32 {
+    (bus.read(pc_addr + 1) as u32) + direct_page_register as u32
+}
+
+/// OPCODE (dp)
+pub fn direct_page_indirect(bus: &Bus, pc_addr: u32, direct_page_register: u16) -> u32 {
+    let addr = direct_page(bus, pc_addr, direct_page_register);
+    let dbr = pc_addr & 0xFF0000;
+    dbr | ((bus.read(addr) as u32) << 8) | (bus.read(addr + 1) as u32)
+}
+
+/// OPCODE [dp]
+pub fn direct_page_indirect_long(bus: &Bus, pc_addr: u32, direct_page_register: u16) -> u32 {
+    let addr = direct_page(bus, pc_addr, direct_page_register);
+    ((bus.read(addr) as u32) << 16) |
+    ((bus.read(addr + 1) as u32) << 8) |
+    (bus.read(addr + 2) as u32)
+}
+
+/// OPCODE addr,X
+/// OPCODE addr,Y
+pub fn absolute_indexed(bus: &Bus, pc_addr: u32, xy: u16) -> u32 {
+    absolute(bus, pc_addr) + (xy as u32)
+}
+
+/// OPCODE long,X
+/// OPCODE long,Y
+pub fn absolute_long_indexed(bus: &Bus, pc_addr: u32, xy: u16) -> u32 {
+    absolute_long(bus, pc_addr) + (xy as u32)
+}
+
+/// OPCODE dp,X
+/// OPCODE dp,Y
+pub fn direct_page_indexed(bus: &Bus, pc_addr: u32, direct_page_register: u16, xy: u16) -> u32 {
+    direct_page(bus, pc_addr, direct_page_register) + (xy as u32)
+}
+
+/// OPCODE (dp,X)
+/// OPCODE (dp,Y)
+pub fn direct_page_indexed_indirect(bus: &Bus, pc_addr: u32, direct_page_register: u16, xy: u16) -> u32 {
+    direct_page_indirect(bus, pc_addr, direct_page_register + xy)
+}
+
+/// OPCODE (dp),X
+/// OPCODE (dp),Y
+pub fn direct_page_indirect_indexed(bus: &Bus, pc_addr: u32, direct_page_register: u16, xy: u16) -> u32 {
+    direct_page_indirect(bus, pc_addr, direct_page_register) + (xy as u32)
+}
+
+/// OPCODE [dp],X
+/// OPCODE [dp],Y
+pub fn direct_page_indirect_long_indexed(bus: &Bus, pc_addr: u32, direct_page_register: u16, xy: u16) -> u32 {
+    direct_page_indirect_long(bus, pc_addr, direct_page_register) + (xy as u32)
+}
+
+/// OPCODE sr,S
+pub fn stack_relative(bus: &Bus, pc_addr: u32, stack_pointer: u16) -> u32 {
+    absolute_indexed(bus, pc_addr, stack_pointer)
+}
+
+/// OPCODE (sr,S),X
+/// OPCODE (sr,S),Y
+pub fn stack_relative_indirect_indexed(bus: &Bus, pc_addr: u32, stack_pointer: u16, xy: u16) -> u32 {
+    absolute_indexed(bus, pc_addr, stack_pointer) + (xy as u32)
+}
+
+#[cfg(test)]
+mod addressing_modes_tests {
+    use super::*;
+
+    #[test]
+    fn test_immediate() {
+        let pc_addr = 0x000000;
+        assert_eq!(immediate(pc_addr),  0x0001);
+    }
+
+    #[test]
+    fn test_absolute() {
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        bus.write(pc_addr + 1, 0x01);
+        bus.write(pc_addr + 2, 0x02);
+        assert_eq!(absolute(&bus, pc_addr), 0x000201);
+
+        let mut bus = Bus::new();
+        let pc_addr = 0x7F0000;
+        bus.write(pc_addr + 1, 0x01);
+        bus.write(pc_addr + 2, 0x02);
+        assert_eq!(absolute(&bus, pc_addr), 0x7F0201);
+    }
+
+    #[test]
+    fn test_absolute_long() {
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        bus.write(pc_addr + 1, 0x01);
+        bus.write(pc_addr + 2, 0x02);
+        bus.write(pc_addr + 3, 0x03);
+        assert_eq!(absolute_long(&bus, pc_addr), 0x030201);
+
+        let mut bus = Bus::new();
+        let pc_addr = 0x7E0010;
+        bus.write(pc_addr + 1, 0x01);
+        bus.write(pc_addr + 2, 0x02);
+        bus.write(pc_addr + 3, 0x03);
+        assert_eq!(absolute_long(&bus, pc_addr), 0x030201);
+    }
+
+    #[test]
+    fn test_direct_page() {
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        assert_eq!(direct_page(&bus, pc_addr, 0x00), 0x000055);
+
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        assert_eq!(direct_page(&bus, pc_addr, 0x01), 0x000056);
+    }
+
+    #[test]
+    fn test_direct_page_indirect() {
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        bus.write(dp as u32, 0x02);
+        bus.write((dp + 1) as u32, 0x01);
+        assert_eq!(direct_page_indirect(&bus, pc_addr, 0x00), 0x000201);
+
+        let pc_addr = 0x7E0010;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        bus.write(dp as u32, 0x02);
+        bus.write((dp + 1) as u32, 0x01);
+        assert_eq!(direct_page_indirect(&bus, pc_addr, 0x00), 0x7E0201);
+
+        let pc_addr = 0x7E0010;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        bus.write((dp + 1) as u32, 0x02);
+        bus.write((dp + 2) as u32, 0x01);
+        assert_eq!(direct_page_indirect(&bus, pc_addr, 0x01), 0x7E0201);
+    }
+
+    #[test]
+    fn test_direct_page_indirect_long() {
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        bus.write(dp as u32, 0x03);
+        bus.write((dp + 1) as u32, 0x02);
+        bus.write((dp + 2) as u32, 0x01);
+        assert_eq!(direct_page_indirect_long(&bus, pc_addr, 0x00), 0x030201);
+
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        bus.write((dp + 1) as u32, 0x03);
+        bus.write((dp + 2) as u32, 0x02);
+        bus.write((dp + 3) as u32, 0x01);
+        assert_eq!(direct_page_indirect_long(&bus, pc_addr, 0x01), 0x030201);
+    }
+
+    #[test]
+    fn test_absolute_indexed() {
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        bus.write(pc_addr + 1, 0x01);
+        bus.write(pc_addr + 2, 0x02);
+        assert_eq!(absolute_indexed(&bus, pc_addr, 0x02), 0x000203);
+
+        let mut bus = Bus::new();
+        let pc_addr = 0x7F0000;
+        bus.write(pc_addr + 1, 0x01);
+        bus.write(pc_addr + 2, 0x02);
+        assert_eq!(absolute_indexed(&bus, pc_addr, 0x02), 0x7F0203);
+    }
+
+    #[test]
+    fn test_absolute_long_indexed() {
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        bus.write(pc_addr + 1, 0x01);
+        bus.write(pc_addr + 2, 0x02);
+        bus.write(pc_addr + 3, 0x03);
+        assert_eq!(absolute_long_indexed(&bus, pc_addr, 0x02), 0x030203);
+
+        let mut bus = Bus::new();
+        let pc_addr = 0x7E0010;
+        bus.write(pc_addr + 1, 0x01);
+        bus.write(pc_addr + 2, 0x02);
+        bus.write(pc_addr + 3, 0x03);
+        assert_eq!(absolute_long_indexed(&bus, pc_addr, 0x02), 0x030203);
+    }
+
+    #[test]
+    fn test_direct_page_indexed() {
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        assert_eq!(direct_page_indexed(&bus, pc_addr, 0x00, 0x01), 0x000056);
+
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        assert_eq!(direct_page_indexed(&bus, pc_addr, 0x01, 0x01), 0x000057);
+    }
+
+    #[test]
+    fn test_direct_page_indexed_indirect() {
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        bus.write((dp + 1) as u32, 0x02);
+        bus.write((dp + 2) as u32, 0x01);
+        assert_eq!(direct_page_indexed_indirect(&bus, pc_addr, 0x00, 0x01), 0x000201);
+
+        let pc_addr = 0x7E0010;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        bus.write((dp + 1) as u32, 0x02);
+        bus.write((dp + 2) as u32, 0x01);
+        assert_eq!(direct_page_indexed_indirect(&bus, pc_addr, 0x00, 0x01), 0x7E0201);
+
+        let pc_addr = 0x7E0010;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        bus.write((dp + 2) as u32, 0x02);
+        bus.write((dp + 3) as u32, 0x01);
+        assert_eq!(direct_page_indexed_indirect(&bus, pc_addr, 0x01, 0x01), 0x7E0201);
+    }
+
+    #[test]
+    fn test_direct_page_indirect_indexed() {
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        bus.write(dp as u32, 0x02);
+        bus.write((dp + 1) as u32, 0x01);
+        assert_eq!(direct_page_indirect_indexed(&bus, pc_addr, 0x00, 0x01), 0x000202);
+
+        let pc_addr = 0x7E0010;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        bus.write(dp as u32, 0x02);
+        bus.write((dp + 1) as u32, 0x01);
+        assert_eq!(direct_page_indirect_indexed(&bus, pc_addr, 0x00, 0x01), 0x7E0202);
+
+        let pc_addr = 0x7E0010;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        bus.write((dp + 1) as u32, 0x02);
+        bus.write((dp + 2) as u32, 0x01);
+        assert_eq!(direct_page_indirect_indexed(&bus, pc_addr, 0x01, 0x01), 0x7E0202);
+    }
+
+    #[test]
+    fn test_direct_page_indirect_long_indexed() {
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        bus.write(dp as u32, 0x03);
+        bus.write((dp + 1) as u32, 0x02);
+        bus.write((dp + 2) as u32, 0x01);
+        assert_eq!(direct_page_indirect_long_indexed(&bus, pc_addr, 0x00, 0x02), 0x030203);
+
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        let dp = 0x55;
+        bus.write(pc_addr + 1, dp);
+        bus.write((dp + 1) as u32, 0x03);
+        bus.write((dp + 2) as u32, 0x02);
+        bus.write((dp + 3) as u32, 0x01);
+        assert_eq!(direct_page_indirect_long_indexed(&bus, pc_addr, 0x01, 0x02), 0x030203);
+    }
+
+    #[test]
+    fn test_stack_relative() {
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        bus.write(pc_addr + 1, 0x01);
+        bus.write(pc_addr + 2, 0x02);
+        assert_eq!(stack_relative(&bus, pc_addr, 0x02), 0x000203);
+
+        let mut bus = Bus::new();
+        let pc_addr = 0x7F0000;
+        bus.write(pc_addr + 1, 0x01);
+        bus.write(pc_addr + 2, 0x02);
+        assert_eq!(stack_relative(&bus, pc_addr, 0x02), 0x7F0203);
+    }
+
+    #[test]
+    fn test_stack_relative_indirect_indexed() {
+        let mut bus = Bus::new();
+        let pc_addr = 0x000000;
+        bus.write(pc_addr + 1, 0x01);
+        bus.write(pc_addr + 2, 0x02);
+        assert_eq!(stack_relative_indirect_indexed(&bus, pc_addr, 0x02, 0x02), 0x000205);
+
+        let mut bus = Bus::new();
+        let pc_addr = 0x7F0000;
+        bus.write(pc_addr + 1, 0x01);
+        bus.write(pc_addr + 2, 0x02);
+        assert_eq!(stack_relative_indirect_indexed(&bus, pc_addr, 0x02, 0x02), 0x7F0205);
+    }
+}
\ No newline at end of file
diff --git a/snes-core/src/utils/mod.rs b/snes-core/src/utils/mod.rs
index 0040cfb..e9761e3 100644
--- a/snes-core/src/utils/mod.rs
+++ b/snes-core/src/utils/mod.rs
@@ -1 +1,2 @@
 pub mod alu;
+pub mod addressing;