SH7751 Datasheet, PDF (192/1224 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

3. Memory Management Unit (MMU)
6. Finally, execute the exception handling return instruction (RTE), terminate the exception
handling routine, and return control to the normal flow. The RTE instruction should be issued
at least one instruction after the LDTLB instruction.
3.7 Memory-Mapped TLB Configuration
To enable the ITLB and UTLB to be managed by software, their contents can be read and written
by a P2 area program with a MOV instruction in privileged mode. Operation is not guaranteed if
access is made from a program in the other area. A branch to an area other than the P2 area should
be made at least 8 instructions after this MOV instruction. The ITLB and UTLB are allocated to
the P4 area in physical address space. VPN, V, and ASID in the ITLB can be accessed as an
address array, PPN, V, SZ, PR, C, and SH as data array 1, and SA and TC as data array 2. VPN,
D, V, and ASID in the UTLB can be accessed as an address array, PPN, V, SZ, PR, C, D, WT, and
SH as data array 1, and SA and TC as data array 2. V and D can be accessed from both the address
array side and the data array side. Only longword access is possible. Instruction fetches cannot be
performed in these areas. For reserved bits, a write value of 0 should be specified; their read value
is undefined.
3.7.1 ITLB Address Array
The ITLB address array is allocated to addresses H'F200 0000 to H'F2FF FFFF in the P4 area. An
address array access requires a 32-bit address field specification (when reading or writing) and a
32-bit data field specification (when writing). Information for selecting the entry to be accessed is
specified in the address field, and VPN, V, and ASID to be written to the address array are
specified in the data field.
In the address field, bits [31:24] have the value H'F2 indicating the ITLB address array, and the
entry is selected by bits [9:8]. As longword access is used, 0 should be specified for address field
bits [1:0].
In the data field, VPN is indicated by bits [31:10], V by bit [8], and ASID by bits [7:0].
The following two kinds of operation can be used on the ITLB address array:
1. ITLB address array read
VPN, V, and ASID are read into the data field from the ITLB entry corresponding to the entry
set in the address field.
2. ITLB address array write
VPN, V, and ASID specified in the data field are written to the ITLB entry corresponding to
the entry set in the address field.
Rev.4.00 Oct. 10, 2008 Page 94 of 1122
REJ09B0370-0400