As another data point, here are the times for 5000 repetitions of tak(18, 12, 6). smlc chunk-per-cont 43.29 smlc one-chunk 34.7 smlc hand patch 25.07 NJ 32.34 C 14.13 "smlc hand patch" is the result of taking the C code from smlc one-chunk and modifying it so that returns do not use the trampoline.