* Request to Get Storage Managed by "GETMAIN" Supervisor Call (SVC 4)
       LA    1,PLIST       Point Reg 1 to GETMAIN/FREEMAIN Parm List
       SVC   4             Issue GETMAIN SVC
       LTR   15,15         Register 15 = 0?
       BZ    GOTSTG         Yes: Got Storage
*      [...]                 No: Handle GETMAIN Failure
GOTSTG L     2,STG@        Load Reg (any Reg) with Addr of Aquired Stg
*      [...]               Continue
* Request to Free Storage Managed by "FREEMAIN" Supervisor Call (SVC 5)
       LA    1,PLIST       Point Reg 1 to GETMAIN/FREEMAIN Parm List
       SVC   5             Issue FREEMAIN SVC
       LTR   15,15         Register 15 = 0?
       BZ    STGFRE         Yes: Storage Freed
*      [...]                 No: Handle FREEMAIN Failure
STGFRE EQU   *             Storage Freed
*      [...]               Continue
*
STG@   DS    A             Address of Stg Area (Aquired or to be Freed)
PLIST  EQU   *             10-Byte GETMAIN/FREEMAIN Parameter List
       DC    A(256)        Number of Bytes; Max=16777208 ((2**24)-8)
       DC    A(STG@)       Pointer to Address of Storage Area
       DC    X'0000'       (Unconditional Request; Subpool 0)