diff --git a/src/hulk/cpu.d b/src/hulk/cpu.d
index 9943cd8..e4d81dd 100644
--- a/src/hulk/cpu.d
+++ b/src/hulk/cpu.d
@@ -155,6 +155,11 @@ ulong read_cr0()
     return __asm!ulong("mov %cr0, %rax", "={rax}");
 }
 
+void write_cr0(ulong v)
+{
+    __asm("mov $0, %cr0", "r", v);
+}
+
 ulong read_cr2()
 {
     return __asm!ulong("mov %cr2, %rax", "={rax}");