IOSECT | Back to Index page

| Prolog Control Block Contents IOSECT DSECT Storage Layout Cross Reference (Contains links to field and bit definitions) |
Programming Interface Information: This information is NOT intended to be used as Programming Interfaces of z/VM.

IOSECT Prolog | Top of page

     NAME       : IOSECT
     DESCRIPTION: I/O Interrupt Save Area
     DSECT      : IOSECT
     FUNCTION   : IOSECT describes the fields used by DMSITI for
                  saving registers, the I/O old PSW, and other
                  data when handling I/O interrupts. IOSECT is
                  pointed to by the AIOSECT field in NUCON.
                  IOSECT is mapped by the IOSECT macro.

IOSECT Control Block Content | Top of page

     IOSECT DSECT
    Top of page

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      IOSECT         I/O Interrupt Save Area
    0000    0 Signed       4 IOSAVE (16)    Register save area
    0040   64 Signed       4 IONTABL        Size of user interrupt table in
                                            bytes
    0044   68 Address      4 AUSRITBL       Address of user interrupt table
    0048   72 Signed       4 *              Length of each entry
    004C   76 Address      4 AUSRILST       Address of last entry in table
    0050   80 Signed       4 OLDEST (4)     Oldest I/O old PSW and CSW
    0060   96 Signed       4 NEXTO (4)      Next oldest I/O old PSW and CSW
    0070  112 Signed       4 IOPSW (2)      Newest I/O old PSW
    0078  120 Signed       4 IOCSW (2)      Newest CSW
           INTBLOK build area
    0080  128 Bitstring    1 IOSINTBK (0)   Start of INTBLOK build area
    0080  128 Bitstring    8 IOSIINFO (0)   Interrupt information
    0080  128 Signed       4 IOSIPARM       For XA/XC, interruption
                                            parameter; for 370, 0
    0084  132 Bitstring    4 IOSIIDNT (0)   For XA/XC, subsystem ID word
                                            (SID); for 370, see individual
                                            components
    0084  132 Signed       2 *              For XA/XC, X'0001'; for 370, 0
    0086  134 Signed       2 IOSISBDV       For XA/XC, subchannel number; for
                                            370, device address
    0088  136 Bitstring    8 IOSIBPSW       I/O old PSW
    0090  144 Bitstring   64 IOSIBIRB (0)   For XA/XC, actual interruption
                                            response block (IRB); for 370,
                                            constructed IRB
    0090  144 Bitstring   12 IOSIBCSW (0)   For XA/XC, actual subchannel
                                            status word (SCSW); for 370,
                                            constructed SCSW
    0090  144 Bitstring    1 IOSIKSLC       Key, S, L, and CC
    0091  145 Bitstring    1 *              FOR XA/XC, MISCELLANEOUS SCSW
                                            BITS; FOR 370, 0
              1... ....      IOSICCWF       X'80' For XA/XC, CCW format; for
                                            370, 0
    0092  146 Bitstring    2 *              For XA/XC, more miscellaneous
                                            SCSW bits; for 370, 0
    0094  148 Address      4 IOSIBCCW       For XA/XC, CCW address; for 370,
                                            X'00' and 3-byte CCW address
    0098  152 Bitstring    1 IOSIDVST       Device status
    0099  153 Bitstring    1 IOSISCST       For XA/XC, subchannel status; for
                                            370, channel status
    009A  154 Signed       2 IOSIRCNT       Residual byte count
    009C  156 Signed       4 * (13)         For XA/XC, extended status word
                                            (ESW) and extended control word
                                            (ECW); for 370, 0
    00D0  208 Bitstring    1 IOSISTAT       Status of INTBLOK information
              1... ....      IOSIFAIL       X'80' IOSIFAIL For XA/XC, if 1,
                                            TSCH failed and IRB is not valid;
                                            for 370, always 0
              .1.. ....      IOSIPSEU       X'40' IOSIPSEU For XA/XC, always
                                            0 (actual information given); for
                                            370, always 1 (constructed, or
                                            "pseudo", information given)
    00D1  209 Bitstring    1 *              Reserved
    00D2  210 Signed       2 IOSDEVNM       Save device addr for user exit
              00000054       IOSIBLEN       *-IOSINTBK Length of INTBLOK
                                            build area
    00D4  212 Bitstring   40 IOSDVBLD       Build area for candidate entry
    00FC  252 Signed       4 IOSEPSW (2)    I/O old PSW for PSW reg setup
    0104  260 Signed       4 HOLD           Holds entry pointer for device
    0108  264 Signed       2 VSTRANGE       Unknown device address
    010A  266 Bitstring    1 IOSTFLAG       I/O status flag
              1... ....      IOSAMSAV       X'80' IOSAMSAV SLIH invoked with
                                            AMODE=31
              .1.. ....      IOSHDEDH       X'40' IOSHDEDH DMSHDEDH is active
              ..1. ....      IOSABN         X'20' IOSABN DMSABN is active
              ...1 ....      IOSUIO         X'10' IOSUIO I/O user routine
    010B  267 Bitstring    1 *              RESERVED FOR FUTURE USE
    010C  268 Address      4 IOSWAITE       Address of waiting routine to be
                                            invoked after WAITD is issued
    0110  272 Signed       4 IOSBASE        DMSITI's base register
    0114  276 Signed       4 IOSAVE2 (24)   Save area used by routines called
                                            from DMSITI
    0174  372 Bitstring   64 IOAREGS        Save area for access registers in
                                            XC machine
    01B4  436 Signed       4 IOSC14SV       Save area for control reg 14
    01B8  440 Signed       4 IOSC14WK       Work area for control reg 14
    01C0  448 Dbl-Word     8 *              Reserved for future use

IOSECT Storage Layout | Top of page

    *** IOSECT - I/O Interrupt Save Area
    *
    *     +-------------------------------------------------------+
    *   0 |                                                       |
    *     =                        IOSAVE                         =
    *     |                                                       |
    *     +---------------------------+---------------------------+
    *  40 |         IONTABL           |         AUSRITBL          |
    *     +---------------------------+---------------------------+
    *  48 |///////////////////////////|         AUSRILST          |
    *     +---------------------------+---------------------------+
    *  50 |                        OLDEST                         |
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  60 |                        NEXTO                          |
    *     |                                                       |
    *     +-------------------------------------------------------+
    *  70 |                        IOPSW                          |
    *     +-------------------------------------------------------+
    *  78 |                        IOCSW                          |
    *     +---------------------------+-------------+-------------+
    *  80 |         IOSIPARM          |/////////////|  IOSISBDV   |
    *     +---------------------------+-------------+-------------+
    *  88 |                       IOSIBPSW                        |
    *     +------+------+-------------+---------------------------+
    *  90 |:IKSLC|//////|/////////////|         IOSIBCCW          |
    *     +------+------+-------------+---------------------------+
    *  98 |:IDVST|:ISCST|  IOSIRCNT   |///////////////////////////|
    *     +------+------+-------------+///////////////////////////|
    *  A0 |///////////////////////////////////////////////////////|
    *     =///////////////////////////////////////////////////////=
    *     |///////////////////////////////////////////////////////|
    *     +------+------+-------------+---------------------------+
    *  D0 |:ISTAT|//////|  IOSDEVNM   |                           |
    *     +------+------+-------------+                           |
    *  D8 |                                                       |
    *     =                       IOSDVBLD                        =
    *     |                           +---------------------------+
    *     |                           |         IOSEPSW-          |
    *     +---------------------------+---------------------------+
    * 100 |          -(0FC)           |           HOLD            |
    *     +-------------+------+------+---------------------------+
    * 108 |  VSTRANGE   |:TFLAG|//////|         IOSWAITE          |
    *     +-------------+------+------+---------------------------+
    * 110 |         IOSBASE           |                           |
    *     +---------------------------+                           |
    * 118 |                                                       |
    *     =                       IOSAVE2                         =
    *     |                           +---------------------------+
    *     |                           |                           |
    *     +---------------------------+                           |
    * 178 |                                                       |
    *     =                       IOAREGS                         =
    *     |                           +---------------------------+
    * 1B0 |                           |         IOSC14SV          |
    *     +---------------------------+---------------------------+
    * 1B8 |         IOSC14WK          |///////////////////////////|
    *     +---------------------------+---------------------------+
    * 1C0 |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    * 1C8
    *
    *** IOSECT - I/O Interrupt Save Area

IOSECT Cross Reference | Top of page

    Symbol         Dspl Value
    -------------- ---- -----
    AUSRILST       004C
    AUSRITBL       0044
    HOLD           0104
    IOAREGS        0174
    IOCSW          0078
    IONTABL        0040
    IOPSW          0070
    IOSABN         010A 20
    IOSAMSAV       010A 80
    IOSAVE         0000
    IOSAVE2        0114
    IOSBASE        0110
    IOSC14SV       01B4
    IOSC14WK       01B8
    IOSDEVNM       00D2
    IOSDVBLD       00D4
    IOSEPSW        00FC
    IOSHDEDH       010A 40
    IOSIBCCW       0094
    IOSIBCSW       0090
    IOSIBIRB       0090
    IOSIBLEN       00D2 00000054
    IOSIBPSW       0088
    IOSICCWF       0091 80
    IOSIDVST       0098
    IOSIFAIL       00D0 80
    IOSIIDNT       0084
    IOSIINFO       0080
    IOSIKSLC       0090
    IOSINTBK       0080
    IOSIPARM       0080
    IOSIPSEU       00D0 40
    IOSIRCNT       009A
    IOSISBDV       0086
    IOSISCST       0099
    IOSISTAT       00D0
    IOSTFLAG       010A
    IOSUIO         010A 10
    IOSWAITE       010C
    NEXTO          0060
    OLDEST         0050
    VSTRANGE       0108

This information is based on z/VM 7.2.0 Last updated on 24 Jun 2020 at 09:36:29 EDT.
Copyright IBM Corporation, 1990, 2020