TODO use de-spacer algorithm for demo of data-dependent fail-first
this one should be possible to do with three sv.cmpi's for each character
(space, backslash, newline) followed by a crweird ORing them all together
into an INT, which is then popcnt'd to find the number of bits actually
copied using a VCOMPRESS mv (or ST).
another way might be to use sv.bc CTR mode which should automatically
decrement CTR by the number of bits in the predicate, saving on a popcnt.