r8a77850anbg Renesas Electronics Corporation., r8a77850anbg Datasheet - Page 232

• Manufacturer Part Number: r8a77850anbg
• Description: Renesas 32-bit Risc Microcomputer Superh? Risc Engine Family
• Manufacturer: Renesas Electronics Corporation.

7. Memory Management Unit (MMU)
• WT: Write-through bit
• UB: Buffered write bit
7.8.4
This LSI supports the following PMB functions.
1. Only memory-mapped write can be used for writing to the PMB. The LDTLB instruction
2. Software must ensure that every accessed P1 or P2 address has a corresponding PMB entry
3. The SH-4A does not guarantee the operation when multiple hit occurs in the PMB. Special
4. The PMB does not have an associative write function.
5. Since there is no PR field in the PMB, read/write protection cannot be preformed. The address
6. Both entries from the UTLB and PMB are mixed and recorded in the ITLB by means of the
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Specifies the cache write mode.
0: Copy-back mode
1: Write-through mode
Specifies whether a buffered write is performed.
0: Buffered write (Data access of subsequent processing proceeds without waiting for the write
1: Unbuffered write (Data access of subsequent processing is stalled until the write has
cannot be used to write to the PMB.
before the access occurs. When an access to an address in the P1 or P2 area which is not
recorded in the PMB is made, this LSI is reset by the TLB. In this case, the accessed address in
the P1 or P2 area which causes the TLB reset is stored in the TEA and code H′140 in the
EXPEVT.
care should be taken when the PMB mapping information is recorded by software.
translation target of the PMB is the P1 or P2 address. In user mode access, an address error
exception occurs.
hardware ITLB miss handling. However, these entries can be identified by checking whether
VPN[31:30] is 10 or not. When an entry from the PMB is recorded in the ITLB, H′00, 01, and
1 are recorded in the ASID, PR, and SH fields which do not exist in the PMB, respectively.
to complete.)
completed.)
PMB Function