CSRC4DAC — Deactivate an extent

Description

Call the CSRC4DAC cell pool service to deactivate a specific extent. Use this service to prepare the cell pool for contraction. You must specify which extent you want to deactivate.

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:	64-bit addressing mode. All input addresses must be valid 64-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:	Must be in a single address or data space. They must be in the primary address space or in an address/data space that is addressable through a public entry on the caller's dispatchable unit access list (DU-AL). All parameter areas, including the parameter list, may reside above 2GB.

Programming requirements

If your program is in AR mode, issue the SYSSTATE macro with ASCENV=AR before you call CSRC4DAC so the CALL macro can generate the correct code for AR mode.

As the program must be running in AMODE 64 to call this service, be sure to issue SYSSTATE AMODE64=YES at the point(s) where the program begins running in AMODE 64.

Before you use cell pool services, you can optionally include the CSRC4ASM macro to generate cell pool services equate (EQU) statements. CSRC4ASM provides the following constants for use in your program:

*  Length of the cell pool anchor data area:
*
CSRC4_ANCHOR_LENGTH     EQU     64
*
*
*  Base length of the cell pool extent data area:
*
CSRC4_EXTENT_BASE       EQU     192
*
*
*  Length of the user-supplied pool name:
*
CSRC4_POOL_NAME_LEN     EQU     8
*
*

Restrictions

After calling CSRC4DAC, you can still free (or return) cells, but you cannot get (or allocate) any others for this extent.

Input register information

Before calling the CSRC4DAC service, the caller does not have to place any information into any register unless using it in register notation for a particular parameter, or using it as a base register.

Output register information

When control returns to the caller, the 64-bit general purpose registers (GPRs) contain:

Register: Contents
0-1: Used as work registers by the system
2-13: Unchanged
14: Used as a work register by the system
15: Return code in low 32 bits. High 32 bits are used as a work area by the system.

When control returns to the caller, the access registers (ARs) contain:

Register: Contents
0-1: Used as work registers by the system
2-14: 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. You must code all parameters on the CALL statement in the order shown.

Syntax	Description
CALL CSRC4DAC	,(cntl_alet ,anchor_addr ,extent_num ,return_code)

Parameters

All input to callable services is in the form of RX-type addresses.

The parameters are explained as follows:

,(cntl_alet: Specifies the fullword variable containing the ALET that identifies the location of the anchor and extents. Initialize the ALET to 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, the value is ignored, but you must code the parameter anyway.
,anchor_addr: Specifies the doubleword variable containing the address of the 64-byte anchor.
,extent_num: Specifies the fullword variable containing the number of the extent that CSRC4DAC will deactivate. The extent number must be within the range 0 to 65536.
,return_code): When CSRC4DAC completes, the fullword variable specified for return_code contains the return code.

ABEND codes

None.

Return and reason codes

When the CSRC4DAC service returns control to your program, GPR 15 (and return_code) 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.
04	04	Meaning: The last cell has been returned to an inactive extent. Action: None required. However, you might take some action depending on your application.
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.
30	48	Meaning: Program error. The extent number is not valid. Action: Make sure the extent number is within the range 0 to 65536.
34	52	Meaning: Program error. You issued the services in the wrong order, or did not issue a necessary service. Action: Check to see if your program passed the wrong extent number. Make sure that the extent is in active state before calling the service.
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.
6C	108	Meaning: Program error or system error. An extent could not be found. Action: Check to see if your program inadvertently overlaid an extent area. Make sure that the anchor address being passed is for the right cell pool.