Some macros that you can issue in AR mode include control parameters,
user parameters, or both. Control parameters refer to the macro parameter
list, and the parameters whose addresses are in the parameter list.
Control parameters control the operation of the macro itself. User
parameters are parameters that a user provides to be passed through
to a user routine. For example, the PARAM parameter on the ATTACHX
macro defines user parameters. The ATTACHX macro passes these parameters
to the routine that it attaches. All other parameters on the ATTACHX
macro are control parameters that control the operation of the ATTACHX
macro.
Note: - User parameters are sometimes referred to as problem program parameters.
- Control parameters are sometimes referred to as system parameters
or control program parameters.
The macros shown in Table 1 allow a caller in AR mode
to pass information in the form of a parameter list (or parameter
lists) to another routine. This table identifies the parameter that
receives the ALET-qualified address of the parameter list and tells
you where the target routine finds the ALET-qualified address.
Table 1. Passing
User Parameters in AR ModeMacro |
Parameter |
Location of User Parameter List Address |
ATTACH/ATTACHX
|
PARAM,VL=1 |
AR/GPR 1 contains the address of a list of
addresses. When either- a 4-bytes-per-entry parameter list or
- an 8-bytes-per-entry parameter list with PLIST8ARALETS=YES
is being used, this list also contains the ALETs associated
with those addresses. (See Figure 1 for
the format of the 4-bytes-per-entry parameter list when it contains
ALETs.) |
ESTAEX |
PARAM |
SDWAPARM contains the address of an 8-byte area,
which contains the address and ALET of the parameter list. |
When an AR mode caller who is using a 4-bytes-per-entry parameter
list passes ALET-qualified addresses to the called program through
PARAM,VL=1 on the ATTACH/ATTACHX macro, the system builds a list formatted as shown
in
Figure 1. The addresses passed to the called program
are at the beginning of the list, and their associated ALETs follow
the addresses. The last address in the list has the high-order bit
on to indicate the
end of the list. For example,
Figure 1 shows the format of a list where an AR mode issuer
of ATTACHX
who is using a 4-bytes-per-entry parameter list has
coded the PARAM parameter as follows:
PARAM=(A,B,C),VL=1
When an AR mode caller who is using an 8-bytes-per-entry parameter
list specifies PLIST8ARALETS=YES, the system builds a parameter list
with the 8-byte addresses at the beginning of the list and their associated
4-byte ALETs following the addresses.
Figure 1. Sample User Parameter
List for Callers in AR Mode
For information about linkage conventions, see the chapter in z/OS MVS Programming: Assembler Services Guide.