def half0

bend-collections-laws-crypto@1.0.0.0 · proofs/math/typed/f64bits.bend:325

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/proofs/lib/logic.bend as L
import bend-collections-laws-crypto@1.0.0.0/proofs/math/typed/width.bend as WW
import bend-collections-laws-crypto@1.0.0.0/proofs/math/typed/u32laws.bend as LW

325# the sign bit c of a 32-bit word is 0 or 1
326def half0(+h: U32) -> {Nat.is_eq(C.half(C.high(31n, v(h))), 0n) == True{} : Bool}:
327  L.subst(Nat, z => {Nat.is_eq(z, 0n) == True{} : Bool}, C.high(32n, v(h)), C.high(1n, C.high(31n, v(h))), WW.high_comp(1n, 31n, v(h)), LW.vb(h))