Output Register Information

When control returns to the caller, the GPRs contain:

Register

Contents

0

Reason code if GR15 return code is non-zero

1

Used as work registers by the system

2-13

Unchanged

14

Used as work registers by the system

15

Return code

When control returns to the caller, the ARs contain:

Register

Contents

0-1

Used as work registers by the system

2-13

Unchanged

14-15

Used as work registers by the system

Some callers depend on register contents remaining the same before and after issuing a service. If the system changes the contents of registers on which the caller depends, the caller must save them before issuing the service, and restore them after the system returns control.