diff --git a/src/Bus.zig b/src/Bus.zig
index ec3ec77..a1190e7 100644
--- a/src/Bus.zig
+++ b/src/Bus.zig
@@ -8,6 +8,7 @@ const Iwram = @import("bus/Iwram.zig");
 const Ppu = @import("ppu.zig").Ppu;
 const Scheduler = @import("scheduler.zig").Scheduler;
 
+const io = @import("bus/io.zig");
 const Allocator = std.mem.Allocator;
 const log = std.log.scoped(.Bus);
 const Self = @This();
@@ -44,7 +45,7 @@ pub fn read32(self: *const Self, addr: u32) u32 {
         0x0000_0000...0x0000_3FFF => self.bios.get32(addr),
         0x0200_0000...0x0203_FFFF => self.iwram.get32(addr - 0x0200_0000),
         0x0300_0000...0x0300_7FFF => self.ewram.get32(addr - 0x0300_0000),
-        0x0400_0000...0x0400_03FE => self.io.read32(addr),
+        0x0400_0000...0x0400_03FE => io.read32(self, addr),
 
         // Internal Display Memory
         0x0500_0000...0x0500_03FF => self.ppu.palette.get32(addr - 0x0500_0000),
@@ -70,7 +71,7 @@ pub fn write32(self: *Self, addr: u32, word: u32) void {
         // General Internal Memory
         0x0200_0000...0x0203_FFFF => self.iwram.set32(addr - 0x0200_0000, word),
         0x0300_0000...0x0300_7FFF => self.ewram.set32(addr - 0x0300_0000, word),
-        0x0400_0000...0x0400_03FE => self.io.write32(addr, word),
+        0x0400_0000...0x0400_03FE => io.write32(self, addr, word),
 
         // Internal Display Memory
         0x0500_0000...0x0500_03FF => self.ppu.palette.set32(addr - 0x0500_0000, word),
@@ -87,7 +88,7 @@ pub fn read16(self: *const Self, addr: u32) u16 {
         0x0000_0000...0x0000_3FFF => self.bios.get16(addr),
         0x0200_0000...0x0203_FFFF => self.iwram.get16(addr - 0x0200_0000),
         0x0300_0000...0x0300_7FFF => self.ewram.get16(addr - 0x0300_0000),
-        0x0400_0000...0x0400_03FE => self.io.read16(addr),
+        0x0400_0000...0x0400_03FE => io.read16(self, addr),
 
         // Internal Display Memory
         0x0500_0000...0x0500_03FF => self.ppu.palette.get16(addr - 0x0500_0000),
@@ -112,7 +113,7 @@ pub fn write16(self: *Self, addr: u32, halfword: u16) void {
         // General Internal Memory
         0x0200_0000...0x0203_FFFF => self.iwram.set16(addr - 0x0200_0000, halfword),
         0x0300_0000...0x0300_7FFF => self.ewram.set16(addr - 0x0300_0000, halfword),
-        0x0400_0000...0x0400_03FE => self.io.write16(addr, halfword),
+        0x0400_0000...0x0400_03FE => io.write16(self, addr, halfword),
 
         // Internal Display Memory
         0x0500_0000...0x0500_03FF => self.ppu.palette.set16(addr - 0x0500_0000, halfword),
@@ -129,7 +130,7 @@ pub fn read8(self: *const Self, addr: u32) u8 {
         0x0000_0000...0x0000_3FFF => self.bios.get8(addr),
         0x0200_0000...0x0203_FFFF => self.iwram.get8(addr - 0x0200_0000),
         0x0300_0000...0x0300_7FFF => self.ewram.get8(addr - 0x0300_0000),
-        0x0400_0000...0x0400_03FE => self.io.read8(addr),
+        0x0400_0000...0x0400_03FE => io.read8(self, addr),
 
         // Internal Display Memory
         0x0500_0000...0x0500_03FF => self.ppu.palette.get8(addr - 0x0500_0000),
@@ -154,7 +155,7 @@ pub fn write8(self: *Self, addr: u32, byte: u8) void {
         // General Internal Memory
         0x0200_0000...0x0203_FFFF => self.iwram.set8(addr - 0x0200_0000, byte),
         0x0300_0000...0x0300_7FFF => self.ewram.set8(addr - 0x0300_0000, byte),
-        0x0400_0000...0x0400_03FE => self.io.write8(addr, byte),
+        0x0400_0000...0x0400_03FE => io.write8(self, addr, byte),
 
         // External Memory (Game Pak)
         0x0E00_0000...0x0E00_FFFF => std.debug.panic("[Bus:8] write 0x{X:} to 0x{X:} in Game Pak SRAM", .{ byte, addr }),
diff --git a/src/bus/io.zig b/src/bus/io.zig
index 134fedb..277c7b2 100644
--- a/src/bus/io.zig
+++ b/src/bus/io.zig
@@ -2,6 +2,7 @@ const std = @import("std");
 
 const Bit = @import("bitfield").Bit;
 const Bitfield = @import("bitfield").Bitfield;
+const Bus = @import("../Bus.zig");
 
 pub const Io = struct {
     const Self = @This();
@@ -66,69 +67,6 @@ pub const Io = struct {
             .keyinput = .{ .raw = 0x03FF },
         };
     }
-
-    pub fn read32(self: *const Self, addr: u32) u32 {
-        return switch (addr) {
-            0x0400_0000 => self.dispcnt.raw,
-            0x0400_0004 => self.dispstat.raw,
-            0x0400_0006 => self.vcount.raw,
-            0x0400_0200 => self.ie.raw,
-            0x0400_0208 => @boolToInt(self.ime),
-            else => std.debug.panic("[I/O:32] tried to read from {X:}", .{addr}),
-        };
-    }
-
-    pub fn write32(self: *Self, addr: u32, word: u32) void {
-        switch (addr) {
-            0x0400_0000 => self.dispcnt.raw = @truncate(u16, word),
-            0x0400_0200 => self.ie.raw = @truncate(u16, word),
-            0x0400_0208 => self.ime = word & 1 == 1,
-            else => std.debug.panic("[I/O:32] tried to write 0x{X:} to 0x{X:}", .{ word, addr }),
-        }
-    }
-
-    pub fn read16(self: *const Self, addr: u32) u16 {
-        return switch (addr) {
-            0x0400_0000 => self.dispcnt.raw,
-            0x0400_0004 => self.dispstat.raw,
-            0x0400_0006 => self.vcount.raw,
-            0x0400_0130 => self.keyinput.raw,
-            0x0400_0200 => self.ie.raw,
-            0x0400_0208 => @boolToInt(self.ime),
-            else => std.debug.panic("[I/O:16] tried to read from {X:}", .{addr}),
-        };
-    }
-
-    pub fn write16(self: *Self, addr: u32, halfword: u16) void {
-        switch (addr) {
-            0x0400_0000 => self.dispcnt.raw = halfword,
-            0x0400_0004 => self.dispstat.raw = halfword,
-            0x0400_0008 => self.bg0cnt.raw = halfword,
-            0x0400_0010 => self.bg0hofs.raw = halfword,
-            0x0400_0012 => self.bg0vofs.raw = halfword,
-            0x0400_0200 => self.ie.raw = halfword,
-            0x0400_0202 => self.irq.raw = halfword,
-            0x0400_0208 => self.ime = halfword & 1 == 1,
-            else => std.debug.panic("[I/O:16] tried to write 0x{X:} to 0x{X:}", .{ halfword, addr }),
-        }
-    }
-
-    pub fn read8(self: *const Self, addr: u32) u8 {
-        return switch (addr) {
-            0x0400_0000 => @truncate(u8, self.dispcnt.raw),
-            0x0400_0004 => @truncate(u8, self.dispstat.raw),
-            0x0400_0200 => @truncate(u8, self.ie.raw),
-            0x0400_0006 => @truncate(u8, self.vcount.raw),
-            else => std.debug.panic("[I/O:8] tried to read from {X:}", .{addr}),
-        };
-    }
-
-    pub fn write8(self: *Self, addr: u32, byte: u8) void {
-        switch (addr) {
-            0x0400_0208 => self.ime = byte & 1 == 1,
-            else => std.debug.panic("[I/0:8] tried to write 0x{X:} to 0x{X:}", .{ byte, addr }),
-        }
-    }
 };
 
 /// Read / Write
@@ -231,3 +169,66 @@ const InterruptRequest = extern union {
     game_pak: Bit(u16, 13),
     raw: u16,
 };
+
+pub fn read32(bus: *const Bus, addr: u32) u32 {
+    return switch (addr) {
+        0x0400_0000 => bus.io.dispcnt.raw,
+        0x0400_0004 => bus.io.dispstat.raw,
+        0x0400_0006 => bus.io.vcount.raw,
+        0x0400_0200 => bus.io.ie.raw,
+        0x0400_0208 => @boolToInt(bus.io.ime),
+        else => std.debug.panic("[I/O:32] tried to read from {X:}", .{addr}),
+    };
+}
+
+pub fn write32(bus: *Bus, addr: u32, word: u32) void {
+    switch (addr) {
+        0x0400_0000 => bus.io.dispcnt.raw = @truncate(u16, word),
+        0x0400_0200 => bus.io.ie.raw = @truncate(u16, word),
+        0x0400_0208 => bus.io.ime = word & 1 == 1,
+        else => std.debug.panic("[I/O:32] tried to write 0x{X:} to 0x{X:}", .{ word, addr }),
+    }
+}
+
+pub fn read16(bus: *const Bus, addr: u32) u16 {
+    return switch (addr) {
+        0x0400_0000 => bus.io.dispcnt.raw,
+        0x0400_0004 => bus.io.dispstat.raw,
+        0x0400_0006 => bus.io.vcount.raw,
+        0x0400_0130 => bus.io.keyinput.raw,
+        0x0400_0200 => bus.io.ie.raw,
+        0x0400_0208 => @boolToInt(bus.io.ime),
+        else => std.debug.panic("[I/O:16] tried to read from {X:}", .{addr}),
+    };
+}
+
+pub fn write16(bus: *Bus, addr: u32, halfword: u16) void {
+    switch (addr) {
+        0x0400_0000 => bus.io.dispcnt.raw = halfword,
+        0x0400_0004 => bus.io.dispstat.raw = halfword,
+        0x0400_0008 => bus.io.bg0cnt.raw = halfword,
+        0x0400_0010 => bus.io.bg0hofs.raw = halfword,
+        0x0400_0012 => bus.io.bg0vofs.raw = halfword,
+        0x0400_0200 => bus.io.ie.raw = halfword,
+        0x0400_0202 => bus.io.irq.raw = halfword,
+        0x0400_0208 => bus.io.ime = halfword & 1 == 1,
+        else => std.debug.panic("[I/O:16] tried to write 0x{X:} to 0x{X:}", .{ halfword, addr }),
+    }
+}
+
+pub fn read8(bus: *const Bus, addr: u32) u8 {
+    return switch (addr) {
+        0x0400_0000 => @truncate(u8, bus.io.dispcnt.raw),
+        0x0400_0004 => @truncate(u8, bus.io.dispstat.raw),
+        0x0400_0200 => @truncate(u8, bus.io.ie.raw),
+        0x0400_0006 => @truncate(u8, bus.io.vcount.raw),
+        else => std.debug.panic("[I/O:8] tried to read from {X:}", .{addr}),
+    };
+}
+
+pub fn write8(self: *Bus, addr: u32, byte: u8) void {
+    switch (addr) {
+        0x0400_0208 => self.io.ime = byte & 1 == 1,
+        else => std.debug.panic("[I/0:8] tried to write 0x{X:} to 0x{X:}", .{ byte, addr }),
+    }
+}