Add architecture-specific GetPteDistance

xtoskrnl/mm/amd64/pagemap.cc

@@ -289,6 +289,28 @@ MM::PageMap::GetPteAddress(IN PVOID Address)
     return (PMMPTE)(PageMapInfo.PteBase + Offset);
 }
 
+/**
+ * Calculates the distance between two PTE pointers.
+ *
+ * @param EndPte
+ *        Pointer to the ending Page Table Entry.
+ *
+ * @param StartPte
+ *        Pointer to the starting Page Table Entry.
+ *
+ * @return This routine returns a signed value representing the number of PTEs between EndPte and StartPte.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+LONG
+MM::PageMap::GetPteDistance(PMMPTE EndPte,
+                            PMMPTE StartPte)
+{
+    /* Return distance between PTE pointers */
+    return ((ULONG_PTR)EndPte - (ULONG_PTR)StartPte) / sizeof(MMPTE);
+}
+
 /**
  * Gets the index of the PTE (Page Table Entry), that maps given address.
  *