Patent ID: 6601151
Filing Date: 2003-07-29
Classification: G06F

Abstract:
A memory access request handling unit for a data processing system that includes a source of memory access requests and a data storage element for servicing memory access requests, the memory access request handling unit comprising:an input for receiving memory access requests; an output for transmitting memory access requests; a queue comprising a plurality of queue elements arranged to receive, and to store temporarily, memory access requests received at the input pending transmission to the output; a list store comprising a plurality of list elements, each arranged to store a list entry derived from a memory access request that has been transmitted from the queue to the output and not yet completed; and comparison logic operable to perform a comparison operation on at least two of the memory access requests stored in at least two of the plurality of queue elements with the list entries stored in the list store, and to select, as a result of the comparison operation, at least one of the at least two of the memory access requests for transmission from the queue to the output, said comparison operation having an operand based upon a probability associated with each of the at least two memory access requests being able to be currently serviced by the data storage element.