Tlb Protection Violation Exception - Hitachi SH7709S Hardware Manual

2. If using software for way selection for entry replacement, write the desired value to the RC
field in MMUCR.
3. Issue the LDTLB instruction to load the contents of PTEH and PTEL into the TLB.
4. Issue the return from exception handler (RTE) instruction to terminate the handler routine and
return to the instruction stream.
3.5.2

TLB Protection Violation Exception

A TLB protection violation exception results when the virtual address and the address array of the
selected TLB entry are compared and a valid entry is found to match, but the type of access is not
permitted by the access rights specified in the PR field. TLB protection violation exception
processing includes both hardware and software operations.
Hardware Operations: In a TLB protection violation exception, the SH7709S hardware executes
a set of prescribed operations, as follows:
1. The VPN field of the virtual address causing the exception is written to the PTEH register.
2. The virtual address causing the exception is written to the TEA register.
3. Either exception code H'0A0 for a load access, or H'0C0 for a store access, is written to the
EXPEVT register.
4. The PC value indicating the address of the instruction in which the exception occurred is
written into SPC (if the exception occurred in a delay slot, the PC value indicating the address
of the related delayed branch instruction is written into SPC).
5. The contents of SR at the time of the exception are written to SSR.
6. The MD bit in SR is set to 1 to place the SH7709S in the privileged mode.
7. The BL bit in SR is set to 1 to mask any further exception requests.
8. The register bank (RB) bit in SR is set to 1.
9. The way that generated the exception is set in the RC field in MMUCR.
10. Execution branches to the address obtained by adding the value of the VBR contents and
H'00000100 to invoke the TLB protection violation exception handler.
Software (TLB Protection Violation Handler) Operations: Software resolves the TLB
protection violation and issues the RTE (return from exception handler) instruction to terminate
the handler and return to the instruction stream.
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