CHAPTER 2 VR4120A
Preliminary User’s Manual S15543EJ1V0UM 181
Figure 2-86. Writeback & Refill Flow
EOD ?
Yes
No
Write-back
to memory
EOD ?
Refill Start
Write data
to cache
Error bit
OK
Bus Error Exception
Cache line
Invalid
Yes
Error
No
Remark Write-back Procedure:
On a store miss write-back, data tag is checked and data is transferred to the write buffer. If an error is detected in
the data field, the write back is not terminated; the erroneous data is still written out to main memory. If an error is
detected in the tag field, the write-back bus cycle is not issued.
The cache data may not be checked during CACHE operation.
2.7.7 Manipulation of the caches by an external agent
The VR4120A does not provide any mechanisms for an external agent to examine and manipulate the state and
contents of the caches.