Sets the error code of the current trap. (This function is for use in trap handlers and such.)
The caller is responsible for making sure there is an active trap which takes an errorcode when making this request.
The caller is responsible for making sure there is an active trap 0e when making this request.
This routine useful when doing try/catch in the hypervisor. Any function which uses temporary trap handlers should probably also use this facility to save the original trap.
Multiple restores of a saved trap is possible.