Renesas SH7781 用户手册

7.   Memory Management Unit (MMU) 

Rev.1.00  Jan. 10, 2008  Page 164 of 1658 
REJ09B0261-0100 

 

The UTLB is used for the following two purposes: 

1.  To translate a virtual address to a physical address in a data access 

2.  As a table of address translation information to be recorded in the ITLB in the event of an 

ITLB miss 

 

The UTLB is so called because of its use for the above two purposes. Information in the address 
translation table located in external memory is cached into the UTLB. The address translation 
table contains virtual page numbers and address space identifiers, and corresponding physical page 
numbers and page management information. Figure 7.6 shows the UTLB configuration. The 
UTLB consists of 64 fully-associative type entries. Figure 7.7 shows the relationship between the 
page size and address format. 

PPN[28:10]

PPN[28:10]

PPN[28:10]

SZ[1:0]

SZ[1:0]

SZ[1:0]

SH

SH

SH

C

C

C

PR[1:0]

PR[1:0]

PR [1:0]

ASID[7:0]

ASID[7:0]

ASID[7:0]

VPN[31:10]

VPN[31:10]

VPN[31:10]

V

V

V

Entry 0

Entry 1

Entry 2

D

D

D

WT

WT

WT

PPN[28:10] SZ[1:0] SH C PR[1:0]

ASID[7:0]

VPN[31:10] V

Entry 63

D WT

 

Legend: 

•  VPN: Virtual page number 

For 1-Kbyte page: Upper 22 bits of virtual address 

For 4-Kbyte page: Upper 20 bits of virtual address 

For 64-Kbyte page: Upper 16 bits of virtual address 

For 1-Mbyte page: Upper 12 bits of virtual address 

•  ASID: Address space identifier 

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, this identifier is compared with the ASID in PTEH when address comparison is 
performed.