def step_fit

bend-collections-laws-crypto@1.0.0.0 · proofs/crypto/poly1305/value.bend:337

import Base
import bend-collections-laws-crypto@1.0.0.0/spec/lib/common.bend as C
import bend-collections-laws-crypto@1.0.0.0/src/crypto/poly1305/limbs.bend as Li
import bend-collections-laws-crypto@1.0.0.0/proofs/crypto/poly1305/arith.bend as A

337# the sum u + ds[0] of one carry step, exact and within 9 + j bits
338def step_fit(+ds: List<&2, U32>, +u: U32, +j: Nat, +hd: {fit_all(ds, Nat.add(8n, j)) == True{} : Bool}, +hu: {C.fits(Nat.add(8n, j), v(u)) == True{} : Bool}) -> {C.fits(Nat.add(9n, j), Nat.add(v(u), v(Li.hd0(ds)))) == True{} : Bool}:
339  A.fits_add(Nat.add(8n, j), v(u), v(Li.hd0(ds)), hu, hd0_fit(ds, Nat.add(8n, j), hd))