There is provided an apparatus, method and medium. The apparatus comprises a store buffer to store a plurality of store requests, where each of the plurality of store requests identifies a storage address and a data item to be transferred to storage beginning at the storage address, where the data item comprises a predetermined number of bytes. The apparatus is responsive to a memory access instruction indicating a store operation specifying storage of N data items, to determine an address allocation order of N consecutive store requests based on a copy direction hint indicative of whether the memory access instruction is one of a sequence of memory access instructions each identifying one of a sequence of sequentially decreasing addresses, and to allocate the N consecutive store requests to the store buffer in the address allocation order.