Guidelines

Each of the user functions is described in detail in the following sections. The following guidelines apply to Monitor I user exit routines:

• All of the user exit routines must be reenterable.
• All user-written exit routines receive control in 31-bit addressing mode.
• The routines must save registers when they receive control and restore registers when they return control. Register 13 contains the address of the register save area; register 14 contains the return address; and register 15 contains the entry address.
• One input parameter that RMF™ passes to each user exit routine (except the tracing routine and the Postprocessor user exit) is the address of a two-word area reserved for the use of your routines. Because these words provide a means of communication between your exit routines, their use should be controlled by conventions agreed upon by your installation.
• RMF passes a phase parameter to each user exit routine except the sampler, the tracing routine, and the Postprocessor user exit. This phase parameter indicates which RMF phase is invoking the user exit.