A network device includes one or more ports, match-action circuitry, and an action processor. The one or more ports are to exchange packets between the network device and a network. The match-action circuitry is to match at least some of the packets to one or more rules so as to set respective actions to be performed, at least one of the actions including a programmable action. The instruction processor is to perform the programmable action by running user-programmable software code. The instruction processor includes architectural registers, one or more of the architectural registers being accessible by the match-action circuitry, and the match-action circuitry is to write into the architectural registers information for performing the programmable action.