Type ASSEMBLE
Source Lines : 222
Fixes Applied : 1
Most Recent Version : Tuesday, December 12, 1978
Last Fix ID : [HRC002DS]
Module
DMSIOW P3031
Function
PLACE THE VIRTUAL CPU IN THE WAIT STATE UNTIL THE COMPLETION
OF AN I/O OPERATION ON ONE OR MORE DEVICES.
Attributes
NUCLEUS RESIDENT, REENTRANT, CALLED VIA SVC OR BALR
IF CALLER'S SYSTEM MASK IS X'00'.
Operation
WAIT LOOKS UP THE FIRST SYMBOLIC DEVICE NAME IN THE
USER-DEFINED INTERRUPT TABLE (IF ANY -- AS
INITIALIZED BY THE HNDINT FUNCTION PROGRAM), OR IN
THE DEVICE TABLE (DEVTAB) IN THE NUCLEUS. IF THE
DEVICE IS NOT IN EITHER TABLE, WAIT RETURNS TO THE
CALLER WITH ERROR CODE 1.
IF THE DEVICE WAS FOUND, WAIT PUTS THE PSEUDO-WAIT
BIT IN THE CORRESPONDING DEVICE TABLE ENTRY ON. WAIT
REPEATS THIS PROCEDURE FOR EACH SYMBOLIC DEVICE NAME
ON THE PARAMETER LIST. IT THEN LOADS A PSW WITH THE
WAIT BIT ON. THIS CAUSES THE SYSTEM TO ENTER THE
WAIT STATE UNTIL AN I/O OPERATION IN ONE OF THE
SPECIFIED DEVICES IS COMPLETED. AFTER THE I/O
OPERATION IS COMPLETED, IOINT RETURNS CONTROL TO
WAIT, WHICH PLACES THE SYMBOLIC NAME OF THE
INTERUPTING DEVICE (THAT IS, THE DEVICE ON WHICH THE
I/O OPERATION WAS COMPLETED) IN THE LAST ENTRY IN THE
PARAMETER LIST AND RETURNS CONTROL TO THE CALLER.
WAIT CAN BE CALLED VIA SVC, OR CAN ALSO BE CALLED BY
BALR IF THE CALLER'S SYSTEM MASK IS X'00'. FOR DISK
RESIDENT PROGRAMS DOING THEIR OWN I/O OPERATIONS WAIT
SHOULD BE CALLED VIA SVC.
Calls to Other Routines
NONE.