1. A printbar comprising: a printhead; and a controller to control the printhead having a plurality of nozzles, the controller to: copy firing instructions assigned over a first network to a plurality of shift registers, to a plurality of parallel registers that correspond to the plurality of shift registers; select a primitive sequence including a respective firing order of a plurality of primitives included in the primitive sequence; provide the primitive sequence, over a second network, to the parallel registers; associate the plurality of primitives with respective subgroups of the plurality of parallel registers, wherein a firing instruction of each of the parallel registers is associated with a primitive of the plurality of primitives; and select a firing instruction of a parallel register included in a subgroup of the parallel registers associated with a first primitive in the primitive sequence to be printed.