QRQ      TITLE 'DMTQRQ     (RSCS)      VM/370 - RELEASE 6'              00001000
*.                                                                      00002000
* MODULE NAME -                                                         00003000
*                                                                       00004000
*        DMTQRQ                                                         00005000
*                                                                       00006000
* FUNCTION -                                                            00007000
*                                                                       00008000
*         THE DMTQRQ  MODULE MANAGES  THE MSUP  SUPERVISOR              00009000
*         STATUS QUEUE FOR OTHER MSUP FUNCTIONS. DMTQRQ IS              00010000
*         INTENDED  FOR  USE  ONLY   WITHIN  THE  SUPERVISOR            00011000
*         ITSELF, AND MUST BE ENTERED WITH ALL PSW MASKS OFF            00012000
*         (EXCEPT MACHINE CHECK).                                       00013000
*                                                                       00014000
* ATTRIBUTES -                                                          00015000
*                                                                       00016000
*        REUSABLE                                                       00017000
*                                                                       00018000
* ENTRY POINTS -                                                        00019000
*                                                                       00020000
*        DMTQRQ -   RESERVE OR RELEASE A SUP QUEUE ELEMENT              00021000
*                                                                       00022000
* ENTRY CONDITIONS -                                                    00023000
*                                                                       00024000
*        GPR1 =  0 IMPLIES A REQUEST TO RESERVE AN ELEMENT              00025000
*             ¬= 0 IMPLIES A REQUEST TO RELEASE THE ELEMENT             00026000
*                WHOSE ADDRESS IS IN GPR1                               00027000
*                                                                       00028000
* EXIT CONDITIONS -                                                     00029000
*                                                                       00030000
*        NORMAL -                                                       00031000
*                                                                       00032000
*              GPR1 =  RESERVD ELEM ADDR ON RESERVE REQ                 00033000
*              GPR15 = X'00' IMPLIES NORMAL REQ COMPLETION              00034000
*                                                                       00035000
*        ERROR -                                                        00036000
*                                                                       00037000
*              GPR15 = X'10' IMPLIES NO ELEMENT AVAILABLE ON            00038000
*                      A RESERVE REQUEST                                00039000
         EJECT                                                          00040000
*                                                                       00041000
* CALLS TO OTHER ROUTINES -                                             00042000
*                                                                       00043000
*        NONE                                                           00044000
*                                                                       00045000
* EXTERNAL REFERENCES -                                                 00046000
*                                                                       00047000
*        DMTVEC -   SUPERVISOR COMMON AREA                              00048000
*                                                                       00049000
* TABLES / WORKAREAS -                                                  00050000
*                                                                       00051000
*        FREE QUEUE ELEMENT                                             00052000
*                                                                       00053000
* REGISTER USAGE -                                                      00054000
*                                                                       00055000
*        GPR0  = UNUSED                                                 00056000
*        GPR1  = FREE ELEMENT POINTER                                   00057000
*        GPR2  = UNUSED                                                 00058000
*        GPR3  = UNUSED                                                 00059000
*        GPR4  = UNUSED                                                 00060000
*        GPR5  = UNUSED                                                 00061000
*        GPR6  = UNUSED                                                 00062000
*        GPR7  = UNUSED                                                 00063000
*        GPR8  = UNUSED                                                 00064000
*        GPR9  = UNUSED                                                 00065000
*        GPR10 = UNUSED                                                 00066000
*        GPR11 = UNUSED                                                 00067000
*        GPR12 = UNUSED                                                 00068000
*        GPR13 = UNUSED                                                 00069000
*        GPR14 = RETURN ADDRESS                                         00070000
*        GPR15 = ENTRY ADDRESS AND RETURN CODE                          00071000
*                                                                       00072000
* NOTES -                                                               00073000
*                                                                       00074000
*        NO VALIDATION IS PERFORMED ON QUEUE ELEMENTS TO BE             00075000
*        RELEASED - THE CALLING ROUTINES ARE RESPONSIBLE FOR            00076000
*        THAT FUNCTION.                                                 00077000
*                                                                       00078000
* OPERATION -                                                           00079000
*                                                                       00080000
*        THE RELEASE OR 'FREE' FUNCTION OF DMTQRQ ENQUEUES              00081000
*        THE ELEMENT SPECIFIED BY THE CALLER TO BE RELEASED             00082000
*        ON THE QUEUE OF FREE SUPERVISOR ELEMENTS, AND                  00083000
*        RETURNS WITHOUT ANY POSSIBLE ERROR CONDITIONS.                 00084000
*                                                                       00085000
*        THE RESERVE OR 'GET' FUNCTION OF DMTQRQ DEQUEUES               00086000
*        THE FIRST ELEMENT ON THE FREE SUPERVISOR ELEMENT QUEUE         00087000
*        AND RETURNS IT'S ADDRESS TO THE CALLER IN GPR1.                00088000
*        IF NO FREE ELEMENT IS AVAILABLE, AN ERROR CODE IS              00089000
*        RETURNED TO THE CALLER IN GPR15.                               00090000
*                                                                       00091000
*.                                                                      00092000
         EJECT                                                          00093000
DMTQRQ   CSECT                                                          00094000
         SPACE                                                          00095000
         USING DMTQRQ,R15                                               00096000
         USING SVECTORS,0          GET SVECTORS ADDRESSABILITY          00097000
         USING FREEE,R1            GET FREE ELEMENT ADDRESSABILITY      00098000
         SPACE                                                          00099000
         LTR   R1,R1               IS REQUEST FOR GET OR FREE?          00100000
         BNZ   QFREE               ADDRESS SUPPLIED - MUST BE FREE      00101000
         ICM   R1,B'1111',FREEQ    R1 ADDR OF START FREE QUEUE, END?    00102000
         BZ    QERROR              NOPE - ERROR RETURN                  00103000
         MVC   FREEQ(4),FREENEXT   SET NEXT ELEMENT AS START OF QUEUE   00104000
         B     QEXIT           AND RETURN WITH ELEMENT ADDRESS IN REG.1 00105000
         SPACE                                                          00106000
QFREE    EQU   *                                                        00107000
         LA    R1,0(R1)    SET HIGH ORDER BYTE TO ZERO JUST IN CASE ... 00108000
         MVI   FREEID,X'00'        CLEAR FREE QUEUE ELEMENT ID FIELD    00109000
         MVC   FREENEXT(4),FREEQ   CHAIN CURRENT FREE QUEUE             00110000
         ST    1,FREEQ        AND SET IT AT THE FRONT OF THE FREE QUEUE 00111000
QEXIT    EQU   *                                                        00112000
         SR    R15,R15             SET RETURN CODE TO ZERO              00113000
         BR    R14                 AND RETURN SUCCESSFULLY              00114000
         SPACE                                                          00115000
QERROR   EQU   *                                                        00116000
         LA    R15,16              LOAD ERROR RETURN CODE               00117000
         BR    R14                 AND RETURN TO CALLER                 00118000
         EJECT                                                          00119000
         COPY  RSSEQU                                                   00120000
         EJECT                                                          00121000
         COPY  SVECTORS                                                 00122000
         EJECT                                                          00123000
         COPY  FREEE                                                    00124000
         END                                                            00125000