HD6417320 RENESAS [Renesas Technology Corp], HD6417320 Datasheet - Page 240

• Manufacturer Part Number: HD6417320
• Description: Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7700 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 4 Memory Management Unit (MMU)
Rev. 3.00 Jan. 18, 2008 Page 178 of 1458
REJ09B0033-0300
[Legend]
VPN:
ASID: Address space identifier
SH:
SZ:
V:
PPN:
PR:
C:
D:
Virtual page number
Upper 19 bits of virtual address for a 1-kbyte page, or upper 20 bits of logical address for a 4-kbyte page. Since VPN
bits 16 to 12 are used as the index number, they are not stored in the TLB entry. Attention must be paid to the
synonym problem (see section 4.4.4, Avoiding Synonym Problems).
Indicates the process that can access a virtual page. In single virtual memory mode and user mode, or in multiple
virtual memory mode, if the SH bit is 0, the address is compared with the ASID in PTEH when address comparison is
performed.
Share status bit
0: Page not shared between processes
1: Page shared between processes
Page-size bit
0: 1-kbyte page
1: 4-kbyte page
Valid bit
Indicates whether entry is valid.
0: Invalid
1: Valid
Cleared to 0 by a power-on reset. Not affected by a manual reset.
Physical page number
Upper 22 bits of physical address. PPN bits 11 to10 are not used in case of a 4-kbyte page.
Protection key field
2-bit field encoded to define the access rights to the page.
00: Reading only is possible in privileged mode.
01: Reading/writing is possible in privileged mode.
10: Reading only is possible in privileged/user mode.
11: Reading/writing is possible in privileged/user mode.
Cacheable bit
Indicates whether the page is cacheable.
0: Non-cacheable
1: Cacheable
Dirty bit
Indicates whether the page has been written to.
0: Not written to
1: Written to
VPN (31 to 17) VPN (11 to 10) ASID V
(15)
Figure 4.7 Virtual address and TLB Structure
31
31
(2)
Virtual address (1-kbyte page)
Virtual address (4-kbyte page)
VPN
VPN
(8)
TLB entry
(1)
12
(19)
PPN
10
11
9
Offset
Offset
PR SZ
(2)
(1) (1) (1) (1)
0
0
C D
SH