question: public static void copy ( long [ ] src , int srcOffset , long [ ] dst , int dstOffset , int len ) { int srcLimit = srcOffset + len ; while ( srcOffset < srcLimit ) { int srcIdx = srcOffset & 63 ; int dstIdx = dstOffset & 63 ; int srcRemainder = 64 - srcIdx ; int dstRemainder = 64 - dstIdx ; int chunkLen = Math . min ( srcRemainder , dstRemainder ) ; long mask = maskBelow ( chunkLen ) << srcIdx ; dst [ dstOffset > > 6 ] |= ( ( src [ srcOffset > > 6 ] & mask ) > > > srcIdx ) << dstOffset ; srcOffset += chunkLen ; dstOffset += chunkLen ; } }
target:  Copies a bit range from one vector to another.