The address space where you can place parameters varies with the
individual service:
- You can place parameters in the primary address space in all service.
- You must place parameters in the primary address space in some
services.
- You can place parameters in any address space in some services.
To identify where you can locate parameters in a service, read
the individual service description.
Programs in AR mode that pass parameters must use an access register
and the corresponding general purpose register together (for example,
access register 1 and general purpose register 1) to identify where
the parameters are located. The access register must contain an access
list entry token (ALET) that identifies the address space where the
parameters reside. The general purpose register must identify the
location of the parameters within the address space.
The only ALETs that MVS™ services typically accept are:
- Zero (0), which specifies that the parameters are in the caller's
primary address space
- An ALET for a public entry on the caller's dispatchable unit access
list (DU-AL)
- An ALET for a common area data space (CADS)
MVS services do not accept the following ALETs,
and you cannot attempt to pass them to a service:
- One (1), which signifies that the parameters are in the caller's
secondary address space
- An ALET that is on the caller's primary address
space access list (PASN-AL) that does not represent a CADS
- An ALET for a private entry on the PASN-AL or
the DU-AL
Throughout, this information uses the term AR/GPR n to
mean an access register and its corresponding general purpose register.
For example, to identify access register 1 and general purpose register
1, this information uses AR/GPR 1.