Storage Management Routine - IBM-REXX

REXX storage routines handle storage and have pools of storage available to satisfy storage requests for REXX processing. If the pools of storage available to the REXX storage routines are depleted, the routines then call the storage management routine to request a storage pool. A storage pool is contiguous storage that can be used by the REXX storage routines to satisfy storage requests for REXX processing.

You can provide your own storage management routine that interfaces with the REXX storage routines. If you provide your own storage management routine, when the pools of storage are depleted, the REXX storage routines will call your storage management routine for a storage pool. If you do not provide your own storage management routine, GETMAIN and FREEMAIN are used to handle storage pool requests. Providing your own storage management routine gives you an alternative to the system using GETMAIN and FREEMAIN.

The storage management routine is called to obtain or free a storage pool for REXX processing. The routine supplies a storage pool that is then managed by the REXX storage routines.

The storage management routine is called when:

• REXX processing requests storage and a sufficient amount of storage is not available in the pools of storage the REXX storage routines use.
• A storage pool needs to be freed. A storage pool may need to be freed when a language processor environment is terminated or when the REXX storage routines determine that a particular pool of storage can be freed.

Specify the name of the storage management routine in the GETFREER field in the module name table.

Entry Specifications

For the storage management replaceable routine, the contents of the registers on entry are described below.

Register 0 Address of the current environment block

Register 1 Address of the parameter list

Registers 2-12 Unpredictable

Register 13 Address of a register save area

Register 14 Return address

Register 15 Entry point address

Parameters

Register 1 contains the address of a parameter list, which consists of a list of addresses. Each address in the parameter list points to a parameter. All parameters are passed on the call. The high-order bit of the last address in the parameter list must be set to 1 to indicate the end of the parameter list. The describes the parameters for the storage management routine.

Parameters for the Storage Management Replaceable Routine

Return Specifications

For the storage management replaceable routine, the contents of the registers on return are:

Registers 0-14 Same as on entry

Register 15 Return code

Return Codes

This shows the return codes for the storage management routine.

Return Codes for the Storage Management Replaceable Routine