def Word64.zigzag
import bend-kit-protobuf@0.2.0.0/protobuf.bend as Protobufimport Base
40def Word64.zigzag(w: Word64) -> Word64:
41 Word64{+h, +l} = w
42 +mask = (0 - (h >> 31n) : U32)
43 Word64{(((h << 1n) .|. (l >> 31n)) .^. mask : U32), ((l << 1n) .^. mask : U32)}