diff --git a/include/coreinit/memorymap.h b/include/coreinit/memorymap.h
index 2565c73c..afdb9118 100644
--- a/include/coreinit/memorymap.h
+++ b/include/coreinit/memorymap.h
@@ -26,6 +26,9 @@ typedef enum OSMemoryMapMode
 uint32_t
 OSEffectiveToPhysical(uint32_t virtualAddress);
 
+BOOL
+OSIsAddressValid(uint32_t virtualAddress);
+
 /**
  * Allocates virtual address range for later mapping.
  *