std::sys contains a set of system-level utility procedures.
|truncate_stack||Removes elements deep in the stack until the depth of the stack is exactly 16. The elements are removed in such a way that the top 16 elements of the stack remain unchanged. If the stack would otherwise contain more than 16 elements at the end of execution, then adding a call to this function at the end will reduce the size of the public inputs that are shared with the verifier.|
Input: Stack with 16 or more elements.
Output: Stack with only the original top 16 elements.