diff --git a/src/core/bus/io.zig b/src/core/bus/io.zig
index 5f76d7c..a0f86d5 100644
--- a/src/core/bus/io.zig
+++ b/src/core/bus/io.zig
@@ -305,6 +305,14 @@ pub fn write(bus: *Bus, comptime T: type, address: u32, value: T) void {
             0x0400_0009 => bus.ppu.bg[0].cnt.raw = setHi(u16, bus.ppu.bg[0].cnt.raw, value),
             0x0400_000A => bus.ppu.bg[1].cnt.raw = setLo(u16, bus.ppu.bg[1].cnt.raw, value),
             0x0400_000B => bus.ppu.bg[1].cnt.raw = setHi(u16, bus.ppu.bg[1].cnt.raw, value),
+            0x0400_0040 => bus.ppu.win.h[0].raw = setLo(u16, bus.ppu.win.h[0].raw, value),
+            0x0400_0041 => bus.ppu.win.h[0].raw = setHi(u16, bus.ppu.win.h[0].raw, value),
+            0x0400_0042 => bus.ppu.win.h[1].raw = setLo(u16, bus.ppu.win.h[1].raw, value),
+            0x0400_0043 => bus.ppu.win.h[1].raw = setHi(u16, bus.ppu.win.h[1].raw, value),
+            0x0400_0044 => bus.ppu.win.v[0].raw = setLo(u16, bus.ppu.win.v[0].raw, value),
+            0x0400_0045 => bus.ppu.win.v[0].raw = setHi(u16, bus.ppu.win.v[0].raw, value),
+            0x0400_0046 => bus.ppu.win.v[1].raw = setLo(u16, bus.ppu.win.v[1].raw, value),
+            0x0400_0047 => bus.ppu.win.v[1].raw = setHi(u16, bus.ppu.win.v[1].raw, value),
             0x0400_0048 => bus.ppu.win.in.raw = setLo(u16, bus.ppu.win.in.raw, value),
             0x0400_0049 => bus.ppu.win.in.raw = setHi(u16, bus.ppu.win.in.raw, value),
             0x0400_004A => bus.ppu.win.out.raw = setLo(u16, bus.ppu.win.out.raw, value),
@@ -462,8 +470,12 @@ pub const BldY = extern union {
     raw: u16,
 };
 
+const u8WriteKind = enum { Hi, Lo };
+
 /// Write-only
 pub const WinH = extern union {
+    const Self = @This();
+
     x2: Bitfield(u16, 0, 8),
     x1: Bitfield(u16, 8, 8),
     raw: u16,
@@ -471,9 +483,18 @@ pub const WinH = extern union {
 
 /// Write-only
 pub const WinV = extern union {
+    const Self = @This();
+
     y2: Bitfield(u16, 0, 8),
     y1: Bitfield(u16, 8, 8),
     raw: u16,
+
+    pub fn set(self: *Self, comptime K: u8WriteKind, value: u8) void {
+        self.raw = switch (K) {
+            .Hi => (@as(u16, value) << 8) | self.raw & 0xFF,
+            .Lo => (self.raw & 0xFF00) | value,
+        };
+    }
 };
 
 pub const WinIn = extern union {