Type ASSEMBLE
Source Lines : 461
Fixes Applied : 1
Most Recent Version : Tuesday, December 12, 1978
Last Fix ID : [R09011DS]
Module
DMSTQQ
Function
TO ALLOCATE A 200-BYTE FIRST CHAIN LINK (FCL) TO A
CALLING PROGRAM.
Attributes
REENTRANT, NUCLEUS-RESIDENT.
Operation
DMSTQQ FIRST CHECKS TO SEE THAT THE DISK IS LOGGED IN
AND READ/WRITE. THE QQMASK TABLE IN THE ADT IS THEN
SEARCHED FOR AN AVAILABLE ENTRY. IF ONE IS FOUND,
THE ADDRESS IN THE TABLE ENTRY IS RETURNED TO THE
CALLER IN REGISTER 1 AND THE ENTRY IN THE TABLE IS
ZEROED. IF NO ENTRY IS FOUND, DMSTRKA IS CALLED TO
GET ANOTHER 800-BYTE BLOCK ADDRESS.
AN ENTRY WILL BE FOUND ONLY FOR A 2314. IF THE
DEVICE IS NOT A 2314 OR IF THE BLOCK NUMBER IS GREATER
THAN 8191 THE ENTIRE BLOCK IS RETURNED TO THE CALLER.
IF THE BLOCK NUMBER IS NOT GREATER THAN 8191, THE
ADDRESS OF THE LAST 200 BYTES IS RETURNED TO THE
CALLER, AND THE ADDRESSES OF THE FIRST 3 SLOTS ARE
PUT IN THE QQMASK TABLE.
NOTES: AT ENTRY, DMSTQQ CHECKS THAT THE POINTER TO
ADT BLOCK IN R1 IS POSITIVE AND NONZERO, THAT THE
DISK REFERENCED THEREBY IS READ-WRITE, AND THAT THE
USER FILE DIRECTORY, INCLUDING THE QQMSK TABLE, IS
INDEED IN MEMORY.
WHEN CALLING DMSTRKA, IF DMSTQQ OBTAINS AN ERROR 4
INDICATING "VERY FEW" RECORDS LEFT, DMSTQQ RETURNS
THE RECORD JUST OBTAINED VIA DMSTRKX BEFORE
RETURNING WITH ERROR-CODE 1 TO THE CALLER, SO THAT
SUFFICIENT RECORDS ARE HELD IN RESERVE TO UPDATE THE
FILE DIRECTORY IN HANDLING THE FULL-DISK SITUATION.
Calls to Other Routines
DMSTRKA, DMSTRKX