Section 3 Memory Management Unit (MMU)
Rev. 5.00 May 29, 2006 page 62 of 698
REJ09B0146-0500
3.3.2
TLB Indexing
The TLB uses a 4-way set associative scheme, so entries must be selected by index. VPN bits 16
to 12 and ASID bits in PTEH 4 to 0 are used as the index number regardless of the page size. The
index number can be generated in two different ways depending on the setting of the IX bit in
MMUCR.
1. When IX = 0, VPN bits 16 to 12 alone are used as the index number
2. When IX = 1, VPN bits 16 to 12 are EX-ORed with ASID bits 4 to 0 to generate a 5-bit index
number
The second method is used to prevent lowered TLB efficiency that results when multiple
processes run simultaneously in the same virtual address space (multiple virtual memory) and a
specific entry is selected by indexing of each process. Figures 3.5 and 3.6 show the indexing
schemes.
31
16
11
12
17
0
31
0
PTEH register
Virtual address
VPN
0
ASID
7
10
Index
ASID(4 to 0)
Exclusive-OR
Ways 0 to 3
VPN(31–17)
VPN(11, 10)
ASID(7–0)
V
0
31
Address array
Data array
PPN(3–0)
PR(1, 0) SZ C
D SH
Figure 3.5 TLB Indexing (IX = 1)
Summary of Contents for SH7706 Series
Page 8: ...Rev 5 00 May 29 2006 page viii of xlviii ...
Page 160: ...Section 5 Cache Rev 5 00 May 29 2006 page 112 of 698 REJ09B0146 0500 ...
Page 370: ...Section 11 Watchdog Timer WDT Rev 5 00 May 29 2006 page 322 of 698 REJ09B0146 0500 ...
Page 554: ...Section 17 Pin Function Controller PFC Rev 5 00 May 29 2006 page 506 of 698 REJ09B0146 0500 ...
Page 576: ...Section 18 I O Ports Rev 5 00 May 29 2006 page 528 of 698 REJ09B0146 0500 ...
Page 746: ...Index Rev 5 00 May 29 2006 page 698 of 698 REJ09B0146 0500 ...
Page 749: ...SH7706 Group Hardware Manual ...