Non-blocking processor bus bridge for network processors or the like

In a bridge coupling between a first bus and a second bus, a method for communicating between the first and second buses comprising:

• A) receiving from the first bus a candidate request having an identification field, the identification field having a value;
• B) matching the identification field value of the candidate request to an identification field value of at least one request buffered in a plurality of FIFO buffers;
• C) entering the candidate request into the FIFO buffer having at least one request therein with an identification field value that matches the identification field value of the candidate request;
• D) entering, if the candidate request was not entered in step C), the candidate request into one of the FIFO buffers having no requests therein or into one of the buffers having at least one request therein with an identification field value that does not match the identification field value of the candidate request;
• E) reading a buffered request from a specified one of the FIFO buffers;
• F) transmitting the read buffered request over the second bus;
• G) receiving a response to the transmitted request from the second bus;
• H) transmitting the received response over the first bus;
• and
• I) removing the request read from the selected one of the FIFO buffers;
• wherein each buffered request has an associated flow index that identifies which one of the FIFO buffers contains the buffered request, and in step C) the candidate request is entered into the one of the FIFO buffers specified by the flow index of one of the buffered requests that has an identification field value that was matched in step B).

A bridge for communicating between a first bus and a second bus, comprising:

• a receiver, coupled to the first bus, adapted to receive candidate requests, each candidate request having an associated identification field, the associated identification field having a value;
• a memory, coupled to the receiver, for storing requests, each request having an associated identification field, and each identification field having a value;
• a plurality of buffers, coupled to the memory, for buffering requests corresponding to those stored in the memory;
• a controller coupled to the memory and the plurality of buffers;
• a transmitter, coupled to the plurality of buffers and the second bus, adapted to transmit a request from a specified one of the buffers for execution by a subsystem coupled to the second bus;
• wherein the controller is adapted to:
• A) match the identification field value of the candidate request to identification field values of requests stored in the memory;
• B) enter the candidate request into the memory and into a) the buffer having at least one buffered request therein with a corresponding identification field value stored in the memory that matches that of the candidate request, b) one of the buffers having no buffered requests therein, or c) one of the buffers having at least one buffered request therein with a corresponding identification field value stored in the memory that does not match the identification field value of the candidate request;
• and
• C) remove the request from the memory and from the specified buffer after the buffered request is executed by the subsystems;
• wherein each stored request has an associated initial identification match field stored in the memory, the initial identification match field indicating the order in which candidate requests are entered into a buffer in step B).