A mechanism is provided for merging in a network processor results from a parser and results from an external coprocessor providing processing support requested by said parser. The mechanism enqueues in a result queue both parser results needing to be merged with a coprocessor result and parser results which have no need to be merged with a coprocessor result. An additional queue is used to enqueue the addresses of the result queue where the parser results are stored. The result from the coprocessor is received in a simple response register. The coprocessor result is read by the result queue management logic from the response register and merged to the corresponding incomplete parser result read in the result queue at the address enqueued in the additional queue.