2.3.3. Hit-Under-Miss

Hit-Under-Miss (HUM) translates a TLB miss transaction and passes the transaction to a downstream slave if the translated TLB miss transaction results in a TLB hit. HUM characteristics for read and write transactions are as follows:

Example 2.1 shows a hit under miss condition.

Example 2.1. Hit under miss

Consider that the write buffer depth is eight and there are two missed write transactions of lengths four and three. Both missed write transactions are stored in the write buffer during the PTWs for the transactions. If you perform another transaction before the missed write transactions are processed, the new transaction is passed through.


If the write buffer is full with missed write transactions, HUM cannot happen.

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