Digi NS9215 Computer Hardware User Manual


 
WORKING WITH THE CPU
MemoryManagement Unit (MMU)
116 Hardware Reference NS9215
Translation
sequence for large
page references
Because the upper four bits of the page index and low-order four bits of the coarse
page table index overlap, each coarse page table entry for a large page must be
duplicated 16 times (in consecutive memory locations) in the coarse page table.
If the large page descriptor is included in a fine page table, the high-order six bits
of the page index and low-order six bits of the fine page table overlap. Each fine
page table entry for a large page must be duplicated 64 times.
31 14 13 0
Translation base
1
Translation table base
31 1413 0
Translation base
2
Table index 0 0
31 2019 0
Table index Page index
First-level descriptor
31 0
Coarse page table base address
2
01
1345
Domain 1
31 0
Coarse page table base address
table index
1615 1211
Modified virtual address
8910
12910
31 1615 121110 9 8 7 6 5 4 3 2 1 0
00L2 table index
01BCAP0AP1AP2AP3Page base address
Page base address
31 01615
Page index
Physical address
Second-level descriptor