Environment

Data areas commonly referenced are mapped by the following mapping macros. IBM® recommends you include them in you function routine:

The function routine receives control in the following environment:

Environment variable	Value
Minimum authorization	Any state, any key, depending on the implementation of the function routine. However, IBM suggests that you process this function in problem state, any key.
Dispatchable unit mode	Task
AMODE	24-bit or 31-bit, depending on the implementation of the function routine. If 24-bit AMODE, the callers of the routine must obtain all their control parameters below 16 megabyte storage so that the serving routine can address them. IBM recommends this program runs in AMODE 31.
Cross memory mode	PASN=HASN=SASN
Interrupt status	Enabled for I/O and external interrupts
Locks	No locks held
Control parameters	Above or below 16 megabytes depending on the implementation of the routine. However, if the routine runs in AMODE 24, the caller must obtain the control parameters and pass to the serving routine below the line so that it can address them.
Recovery	The function routine should provide an ESTAE-type recovery environment. See z/OS MVS Programming: Authorized Assembler Services Guide for more information on how to set up an ESTAE-type recovery environment.

Figure 1 shows the environment on entry to the function routine for SSI function code 54.

Figure 1. Environment on Entry to the Function Routine for SSI Function Code 54