Exit routines are considered components of the operating system. Since privileged system interfaces are only available in the 31-bit format and do not depend on the addressing mode, it is necessary to adapt the relevant routines. Instead of switching the addressing mode to the appropriate interfaces (a hardware-dependent process), the exit routines must run in the same addressing mode as the system.
Exit routines therefore:
must be able to run in any addressing mode (AMODE ANY)
must adhere to the programming regulations valid for the operating system
must have the attribute RMODE ANY
EXIT routines can access address fields, the contents of which are provided by user programs (e.g. in parameter lists). These fields must be cleaned up by the system exit routines before further processing or before they have to be prepared for 31-bit addressing.
System Exits for systems with x86 architecture
Like all routines that run as privileged routines, system exit routines must also run directly (native) on the CPU, this means that they must run as x86 code directly on the x86 CPU.
If you wish to use system exits, you must ensure that the source code of the system exits is modified and then compiled again.
When doing this, Fujitsu Technology Solutions is able to provide support and advice if required. For information, contact your Service representative.