Method and apparatus for non-sequential resource access

Abstract

A method and apparatus for non-sequential access to shared resources in a multiple requestor system uses a variety of tags to effectively re-order the data at its destination. In simplest form, the tag directs switching logic to where in a buffer to locate another tag for direction information or where in a buffer or processor (register) to put the response associated with the tag. For example, loading data from memory requires that the requestor provide a request signal, an address, and a request tag. The request signal validates the address and request tag. The address specifies the location of the requested data in memory. The request tag specifies where to put the data when it is returned to the processor. The switching logic for the requestor includes a tag queue for storing the request tags associated with the resource requests, logic means for associating the respective request tag from the tag queue with a resource response, and means for returning the resource response and respective request tag to the requestor. The switching logic associated with the shared resource includes switching means to route the request into and out of the shared resource, control logic to correctly route the request, logic to handle multiple decision requests, and logic to store or retrieve the ultimate data entity being requested.