A permute unit includes permute logic and a crossbar working in cycles defined by clocking signals and generates one valid output vector per cycle by treating two parallel input vectors per cycle. The permute unit is double pumped by performing two inner cycles per outer cycle defined by the clocking signals. In the first inner cycle, first halves of both input vectors are treated. In the second inner cycle, second halves of both input vectors are treated and a valid output vector is generated from the results of the treatments within the first and the second inner cycles.