fact: Fixpoint lowWithZeroExtend m {n} : BITS n -> BITS m := if n is _.+1 then fun p => let (p,b) := splitlsb p in if m is m'.+1 then joinlsb (@lowWithZeroExtend m' _ p, b) else zero 0 else fun p => zero m.
imports: Coq(ZArith.ZArith Strings.String) mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool eqtype ssrnat seq fintype tuple zmodp)