Type ASSEMBLE
Source Lines : 551
Fixes Applied : 1
Most Recent Version : Tuesday, December 12, 1978
Last Fix ID : [R09503DS]
Module
DMSSTG
Function
THE DMSSTG ROUTINE PROCESSES CMS CALLS TO DMSSTGST
DMSSTGSB (STRINIT), DMSSTGAT, DMSSTGCL AND DMSSTGSV.
Attributes
NUCLEUS RESIDENT, RE-ENTRANT
Operation
IF A CMS ROUTINE CALLS THE STORAGE INITIALIZATION
ROUTINE (STRINIT) IN DMSSTG, STRINIT
RESETS THE FREE STORAGE EXTENTS AND EFFECTIVELY FREES
ANY STORAGE THAT WAS PREVIOUSLY GETMAINED.
IF A CMS ROUTINE CALLS DMSSTGCL IN DMSSTG, DMSSTGCL
ISSUES STAE, SPIE, TTIMER, AND STAX CANCEL MACROES
TO CANCEL ANY OUTSTANDING OS EXIT ROUTINES. IT ALSO
CALLS DMSLGTA, DMSSLNAB, AND DMSFRET TO FREE ANY TXTLIB,
MACLIB, OR LINK TABLES LEFT AROUND FROM PREVIOUS OS
PROGRAMS. CONTROL IS THEN RETURNED TO THE USER.
THE GETBLK ROUTINE IN DMSSTG SEARCHES THE FREE CHAIN
FOR A BLOCK OF FREE STORAGE LARGE ENOUGH TO MEET THE
CALLER'S NEEDS. WHEN IT FINDS ONE, IT EITHER RESETS
THE BLOCK LENGTH OR, IF ALL THE BLOCK IS NEEDED,
DELETES IT AND RETURNS CONTROL TO THE CALLER. IF A
LARGE ENOUGH BLOCK CANNOT BE FOUND
CONTROL IS RETURNED TO THE CALLER WITH AN ERROR CODE IN
REGISTER 15.
THE FREEBLK ROUTINE IN DMSSTG RETURNS A BLOCK OF
STORAGE TO THE FREE CHAIN. IF THE ADDRESS PASSED IT IS
BAD, THE FREEBLK ROUTINE ISSUES AN ABEND. IF THE BLOCK
IT IS FREEING IS CONTIGUOUS TO ANY OTHER FREE BLOCK IN
CORE, THE FREEBLK ROUTINE WILL COMBINE THE TWO BLOCKS.
UPON SUCCESSFUL COMPLETION CONTROL IS RETURNED TO THE
CALLER.
PREVIOUS STORAGE ALLOCATION REQUESTS MAINTAIN A
CHAIN OF POINTERS TO DISCONNECTED AREAS OF FREE CORE
EACH LINK +00 IS FREPTR - POINTER TO NEXT LINK
ZERO IF LAST IN CHAIN
+04 IS FRELEN - LENGTH OF FREE AREA
FRELST POINTS TO THE FIRST LINK IN THE CHAIN
OF DISCONNECTED AREAS
FSTFRE HOLDS THE ORIGINAL BEGINNING OF USER FREE STORAGE
LENFRE HOLDS THE LENGTH OF THAT AREA
NUCON LOCATION MAINHIGH HOLDS THE LOWER BOUND FOR EXTEND.
NUCON LOCATION FREELOWE (LOWEXT) HOLDS THE UPPER BOUND FOR
GETMAIN.
Calls to Other Routines
DMSSVT, DMSSAB, DMSFRE, DMSLGTA, DMSSLNAB