ProofBytes.byte_shrn.k: def of lawful-words@0.1.0.0
Import: import lawful-words@0.1.0.0/proof_bytes.bend as ProofBytes
Lines 669-680 of lawful-words@0.1.0.0/proof_bytes.bend: https://jend.leeeet.dev/read.txt?path=lawful-words@0.1.0.0/proof_bytes.bend&start_line=669&end_line=680

import Base
import lawful-words@0.1.0.0/defs.bend as D

def byte_shrn.k(+w: U32, +s: Nat, +j: Nat, +k: Nat) ->
  {D.bit(D.byte(U32.shrn(w, Nat.mul(8n, s)), j), k) == D.bit(D.byte(w, Nat.add(j, s)), k) : Bool}:
  +l = Nat.is_lt(k, 8n)
  +i = Nat.add(Nat.mul(8n, j), k)
  %Equal.sym(Bool, D.bit(D.byte(U32.shrn(w, Nat.mul(8n, s)), j), k), Bool.and(l, D.bit(U32.shrn(w, Nat.mul(8n, s)), i)), bit_byte(U32.shrn(w, Nat.mul(8n, s)), j, k)) :
    {_ == D.bit(D.byte(w, Nat.add(j, s)), k) : Bool}
  %Equal.sym(Bool, D.bit(U32.shrn(w, Nat.mul(8n, s)), i), D.bit(w, Nat.add(i, Nat.mul(8n, s))), bit_shrn(w, Nat.mul(8n, s), i)) :
    {Bool.and(l, _) == D.bit(D.byte(w, Nat.add(j, s)), k) : Bool}
  %Equal.sym(Bool, D.bit(D.byte(w, Nat.add(j, s)), k), Bool.and(l, D.bit(w, Nat.add(Nat.mul(8n, Nat.add(j, s)), k))), bit_byte(w, Nat.add(j, s), k)) :
    {Bool.and(l, D.bit(w, Nat.add(i, Nat.mul(8n, s)))) == _ : Bool}
  %idx_add(j, s, k) : {Bool.and(l, D.bit(w, Nat.add(i, Nat.mul(8n, s)))) == Bool.and(l, D.bit(w, _)) : Bool}
  {==}

Uses (14):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool.and
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.sym
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.add
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.is_lt
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.mul
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.shrn
  https://jend.leeeet.dev/definition.txt?path=lawful-words@0.1.0.0/defs.bend&name=bit
  https://jend.leeeet.dev/definition.txt?path=lawful-words@0.1.0.0/defs.bend&name=byte
  https://jend.leeeet.dev/definition.txt?path=lawful-words@0.1.0.0/proof_bytes.bend&name=bit_byte
  https://jend.leeeet.dev/definition.txt?path=lawful-words@0.1.0.0/proof_bytes.bend&name=bit_shrn
  https://jend.leeeet.dev/definition.txt?path=lawful-words@0.1.0.0/proof_bytes.bend&name=idx_add