Constant TRUNCATE_STACK_PROC 

pub const TRUNCATE_STACK_PROC: &str = "
@locals(4)
proc truncate_stack
     loc_storew_be.0 dropw movupw.3
    sdepth neq.16
    while.true
        dropw movupw.3
        sdepth neq.16
    end
    loc_loadw_be.0
end
";

A source code of the truncate_stack procedure.