Using the ESPIE macro

The ESPIE macro extends the functions of the SPIE macro to callers in 31-bit addressing mode. The options that you can specify using the ESPIE macro are:

SET to establish an ESPIE environment (that is, specify the interruptions for which the user-exit routine will receive control)
RESET to delete the current ESPIE environment and restore the SPIE/ESPIE environment specified
TEST to determine the active SPIE/ESPIE environment

If you specify ESPIE SET, you pass the following information to the system:

A list of the program interruptions to be handled by the exit routine
The location of the exit routine
The location of a user-defined parameter list

The system returns either a token representing the previously active SPIE or ESPIE environment, or a token of zeroes if there was none.

If you code ESPIE RESET, you pass the token, which was returned when the ESPIE environment was established, back to the system. The SPIE or ESPIE environment corresponding to the token is restored. If you pass a token of zero with RESET, all SPIE and ESPIE environments are deleted. ESPIE RESET must not be issued from an ESPIE exit. To remove the current ESPIE exit, set the EPIEPERC bit and specify the RESET token in EPIETOK. See Requesting percolation from an ESPIE exit for more information.

If you specify ESPIE TEST, you will be able to determine the active SPIE or ESPIE environment. ESPIE TEST sets return codes to indicate which type of exit is active, if any, and if one or the other is active, provides information about the exit in a parameter list. Refer to the TEST parameter on the ESPIE macro for a description of the return codes, and the information that is returned in the parameter list.

If an ESPIE environment is active and you issue a SPIE macro to specify interruptions for which a SPIE exit routine is to receive control, the system returns the address of a system-generated PICA in register 1. Do not modify the contents of the system-generated PICA; use the address to restore the previous ESPIE environment.

For a data exception,an ESPIE routine will receive the DXC value in its parameter area, and should use this value rather than the value in the Floating Point Control (FPC) register.

If a retry is to be done, an ESPIE routine can manually change the value(s) of the FPR(s) and FPC register. Changes to the non-volatile fields (i.e., the IEEE settings) in the FPC register must be made carefully since this could affect the processing of the rest of the current program, and possibly subsequent programs.