SRBTIMER — Establish time limit for system service

Description

The SRBTIMER macro is used to establish a time limit for a system service running in SRB mode. Time accumulates while the service is running; when the time limit expires, the service abends with a system completion code of X'05B'. The service can retry following the 05B ABEND.

The caller can cancel an established time limit by reissuing the macro and specifying a time limit of zero. The caller can also override the established time limit with a subsequent SRBTIMER macro.

Environment

These are the requirements for the caller:

Environmental factor	Requirement
Minimum authorization:	Supervisor state and key 0
Dispatchable unit mode:	SRB
Cross memory mode:	PASN=HASN=SASN
AMODE:	24- or 31-bit
ASC mode:	Primary
Interrupt status:	Enabled for I/O and external interrupts
Locks:	No requirement
Control parameters:	Must be in primary address space

Programming requirements

None.

Restrictions

None.

Input register information

Before issuing the SRBTIMER macro, the caller must ensure that general purpose register 13 points to a standard 72-byte save area addressable in primary mode.

Output register information

When control returns to the caller, the 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

When control returns to the caller, the ARs contain:

Register: Contents
0-1: Used as work registers by the system
2-13: Unchanged
14-15: Used as work registers by the system

Performance implications

None.

Syntax

The SRBTIMER macro is written as follows:

Syntax	Description

`name`	`name`: Symbol. Begin `name` in column 1.

␢	One or more blanks must precede SRBTIMER.

SRBTIMER

␢	One or more blanks must follow SRBTIMER.

LIMIT=`stor addr`	`stor addr`: RX-type address or register (0) or (2) - (12).

,ERRET=`err rtn addr`	`err rtn addr`: RX-type address or register (2) - (12).

Parameters

The parameters are explained as follows:

LIMIT=stor addr: Specifies the virtual storage address of a doubleword field on a doubleword boundary that contains the time limit. The time limit is in the form of a signed 64-bit binary number and must be positive in order for time to elapse. A negative number causes immediate expiration of the time limit. Bit 51 of the binary number is approximately equivalent to one microsecond. If you specify a value greater than 208 days, the control program changes the value to 208 days. The resolution of the timer is model dependent. See Principles of Operation for details concerning the timer facility.
,ERRET=err rtn addr: Specifies the address of the routine to be given control when the SRBTIMER function encounters damaged clocks.

ABEND codes

None.

Return codes

When SRBTIMER macro returns control to your program, GPR 15 contains a hexadecimal return code.

Table 1. Return Codes for the SRBTIMER Macro
Return Code	Meaning and Action
00	Meaning: The time limit was successfully established. Action: None.
10	Meaning: The issuer is not in SRB mode. No timing is performed. Action: Ensure that the requesting program is running in SRB mode, or use STIMER or STIMERM instead.