pages, the L2 entry contains a 20-bit pointer to the base address of a 4-KB page in main memory.For large pages, the structure is more complex. As with virtual addresses for small pages, a virtual address for a large page structure includes a 12-bit index into the level one table and an 8-bit index into the L2 table. For the 64-KB large pages, the page index portion of the virtual address must be 16 bits. To accommodate all of these bits in a 32-bit format, there is a 4-bit overlap between the page index field and the L2 table index field. ARM accommodates this overlap by requiring that each page table entry in a L2 page table that supports large pages be replicated 16 times. In effect, the size of the L2 page table is reduced from 256 entries to 16 entries, if all of the entries refer to large pages. However, a given L2 page can service a mixture of large and small pages, hence the need for the replication for large page entries.
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