Possibly. I guess the other part that gets me is that you could make the straight-line sequence quite a bit shorter (and with a constant stack footprint) by reo

Possibly. I guess the other part that gets me is that you could make the straight-line sequence quite a bit shorter (and with a constant stack footprint) by reordering stack arguments slightly. Their code starts with a value on the stack, primes the unrolled loop and then goes into a series of nested constructs like: DUP X1 = SWAP DUP X2 = SWAP DUP X3 = SWAP DUP X4 = ... SWAP DROP OR OR OR This builds up a growing mound of flags on the stack and then collapses them down at the end. As the mound is built, the value is constantly flipped up to the top of the stack and then covered with a flag. A better way to do this would be to collapse the flags as you go: DUP X1 = OVER X2 = OR OVER X3 = OR ... SWAP XN = OR