CSRPRGT1 — Allocate a cell from a cell pool (register interface)

Description

Call the CSRPRGT1 cell pool service to allocate a cell from the cell pool using the register interface, if your program cannot obtain storage for a parameter list. CSRPRGT1 allocates cells from the lowest- to highest-numbered active extents, and within each extent, from the lowest to highest cell address. (The CSRPRGT service provides the same function but slightly slower performance.)

Environment

The requirements for the caller are:

Environmental factor	Requirement
Minimum authorization:	Problem state with PSW key 8-15
Dispatchable unit mode:	Task or SRB
Cross memory mode:	Any PASN, any HASN, any SASN.
AMODE:	24- or 31-bit addressing mode. Nucleus-resident code must be in 31-bit addressing mode when calling the service. All input addresses must be valid 31-bit addresses.
ASC mode:	Primary or AR mode. (If the anchor and the extents are located in a data space, the caller must be in AR mode.)
Interrupt status:	Enabled or disabled for I/O and external interrupts
Locks:	The caller may hold locks, but is not required to hold any.
Control parameters:	None.

Programming requirements

Before you use cell pool services, you can optionally include the CSRCPASM macro to generate cell pool services equate (EQU) statements. CSRCPASM provides the following constants for use in your program:

*  Length of the cell pool anchor data area:
*
CSR_ANCHOR_LENGTH     EQU     64
*
*
*  Base length of the cell pool extent data area:
*
CSR_EXTENT_BASE       EQU     128
*
*
*  Length of the user-supplied pool name:
*
CSR_POOL_NAME_LEN     EQU     8
*
*

Restrictions

None.

Input register information

Before calling the CSRPRGT1 service, the caller must ensure that the following access registers (ARs) and general purpose registers (GPRs) contain the specified information:

Register: Contents
AR 1: The ALET used to access all the cell storage areas. Specify 0 if your program is running in AR mode and the anchor and extents are in the primary address space. If your program is running in primary ASC mode, CSRPRGT1 ignores the value.
GPR 1: The anchor address
GPR 13: The address of a 144-byte save area that your program provides. The system does not change the first 8 bytes or the last 8 bytes of this area.

Output register information

When control returns to the caller, the GPRs contain:

Register: Contents
0: Used as a work register by the system
1: Address of the allocated cell
2-13: Unchanged
14: Used as a work register by the system
15: Return code

When control returns to the caller, the ARs contain:

Register: Contents
0: Used as a work register by the system
1-14: Unchanged
15: Used as a work register 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.

Performance implications

None.

Syntax

Write the call as shown on the syntax diagram.

Syntax	Description
CALL CSRPRGT1

Parameters

See Input register information.

ABEND codes

None.

Return and reason codes

When the CSRPRGT1 service returns control to your program, GPR 15 contains one of the following return codes:

Hexadecimal Return Code	Decimal Return Code	Meaning and Action
00	00	Meaning: The operation was successful. Action: None.
08	08	Meaning: Program error. There were no available cells in the pool. Action: Retry the request one or more times. If the problem persists, consider freeing existing cells, adding new cells to the cell pool, or both.
1C	28	Meaning: Program error. The anchor address is not valid. Action: Check to see if your program passed the wrong anchor address or inadvertently overlaid the anchor area.
64	100	Meaning: Program error or system error. An extent chain was broken. Action: Check to see if your program inadvertently overlaid an extent area. Make sure that no extent belongs to more than one cell pool.
68	104	Meaning: Program error or system error. An extent chain is circular. Action: Check to see if your program inadvertently overlaid an extent area. Make sure that no extent belongs to more than one cell pool.
74	116	Meaning: Program error or system error. An extent has been overlaid. Action: Check to see if your program inadvertently overlaid an extent area. Make sure that no extent belongs to more than one cell pool.