Address translation in a data processing apparatus

A method of data processing comprising the steps of:

• performing, by data processing circuitry, data processing operations on data items stored in a memory and retrieved via a memory hierarchy;
• storing address translations between first set memory addresses and second set memory addresses in address translation storage;
• detecting an address translation between the first set memory address and the second set memory address has been stored in the storing address translations step and responding to a request issued as part of performing data processing operations comprising a first set memory address to return a response comprising a second set memory address;
• detecting the address translation between the first set memory address and the second set memory address has not been stored in the storing address translations step and forwarding the request towards the memory in the memory hierarchy;
• storing entries for received requests from the data processing circuitry in a pending request storage prior to being received by the address translation storage;
• performing a memory address comparison of the first set memory address of the request with the first set memory address of an earlier request indicated by a stored entry of the pending request storage;
• determining that the memory address comparison indicates that the earlier request has been forwarded towards the memory and that an expected response to the earlier request will provide the address translation, and in response to the determining, intercepting the request to delay its reception by the address translation storage;
• and
• detecting the expected response to the earlier request providing the address translation and releasing the request to the address translation storage.

Apparatus for data processing comprising:

• means for performing data processing operations on data items stored in a memory and retrieved via a memory hierarchy;
• means for storing address translations between first set addresses and second set addresses;
• means for responding to a request issued by the means for performing data processing operations comprising a first set address to return a response comprising a second set address if an address translation between the first set address and the second set address has been stored in the means for storing address translations;
• means for forwarding the request towards the memory in the memory hierarchy if the address translation between the first set address and the second set address has not been stored in the means for storing address translations;
• means for storing entries for received requests in a pending request storage from the means for performing data processing operations prior to being received by the means for storing address translations, for performing in response to reception of the request a memory address comparison of the first set memory address of the request with the first set memory address of an earlier request indicated by a stored entry of the pending request storage, and for intercepting the request to delay its reception by the means for storing address translations if the memory address comparison is indicative that the earlier request has been forwarded towards the memory and an expected response to the earlier request will provide the address translation;
• and
• means for releasing the request to the means for storing address translations in response to the earlier request providing the address translation.