1 files changed, 22 insertions, 0 deletions
diff --git a/arch/x86_64/include/x86_64/memory/page_utilities.hpp b/arch/x86_64/include/x86_64/memory/page_utilities.hpp
new file mode 100644
index 0000000..efd1b80
--- /dev/null
+++ b/arch/x86_64/include/x86_64/memory/page_utilities.hpp
@@ -0,0 +1,22 @@
+#ifndef TEACHOS_X86_64_PAGE_UTILITIES_HPP
+#define TEACHOS_X86_64_PAGE_UTILITIES_HPP
+
+#include "kapi/memory.hpp"
+
+#include <cstddef>
+
+namespace teachos::memory::x86_64
+{
+
+  template<std::size_t Level>
+    requires(Level > 0uz && Level < 5uz)
+  constexpr auto pml_index(page page) noexcept -> std::size_t
+  {
+    constexpr auto shift_width = (Level - 1) * 9;
+    constexpr auto index_mask = 0x1ffuz;
+    return page.number() >> shift_width & index_mask;
+  }
+
+}  // namespace teachos::memory::x86_64
+
+#endif
+\ No newline at end of file