def mask

bend-collections-laws-crypto@1.0.0.0 · spec/crypto/blake/blake2b.bend:216

import Base

216# The word holding block bytes pos..pos+3 when only `remain` bytes are message:
217# the bytes at or past `remain` are zero padding.
218def mask(w: U32, +pos: Nat, +remain: Nat) -> U32:
219  keep(w,Nat.sub(remain,pos))