Environment

Review Function Routines/Function Codes, which describes both the general environment on entry to your function routine and other programming considerations that your function routine should take into account.

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

IEFSSOBH
IEFJSSIB
BLSABDPL

The function routine receives control in the following environment:

Environment variable	Value
Minimum authorization	Supervisor state with PSW key 0
Dispatchable unit mode	Task
AMODE	24-bit or 31-bit
Cross memory mode	PASN=HASN=SASN
ASC mode	Primary
Interrupt status	Enabled for I/O and external interrupts
Locks	No locks held
Control parameters	The SSIB, SSOB, and ABDPLcontrol blocks reside in storage below 16 megabytes.
Recovery	The function routine should provide an ESTAE-type recovery environment. For more information on how to set up an ESTAE-type recovery environment, see the topic on writing recovery routines in z/OS MVS Programming: Authorized Assembler Services Guide

Figure 1 shows the environment on entry to the function routine for SSI function code 48.

Figure 1. Environment on Entry to the Function Routine for SSI Function Code 48