Programming Interface Information: This information is NOT intended to be used as Programming Interfaces of z/VM.

#### DUCT

Prolog

Control Block Contents
DUCT DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### DUCT Prolog

     Name       : HCPDUCT
     Description: Dispatchable Unit Control Table
     DSECT      : DUCT
     Function   : The DUCT maps the storage associated with the
                  Dispatchable Unit Control Table
     Located by : The DUCTO in CR2
     Created by : None.
     Deleted by : None.
     References : None.
     Serialized : When used to map a guest DUCT, the DUCT is serialized by
                  instruction stream serialization.
     Notes      : None.

#### DUCT Control Block Content

#### DUCT DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      DUCT           Dispatchable Unit Control Table
    0000    0 Signed       4 DUIBM1         Reserved for IBM use
    0004    4 Signed       4 DUIBM2         Reserved for IBM use
    0008    8 Signed       4 *              Reserved for IBM use
    000C   12 Signed       4 DUIBM4         Reserved for IBM use
    0010   16 Signed       4 DUALD          Dispatchable-Unit Access- List
                                            Designation
         ** From this point on, the DUCT varies by guest mode ** (ESA/390 vs
         ESAME) and by addressing mode (24-bit, ** 31-bit or 64-bit) when CP is
         in ESAME mode.
         * ESA/390 mode guest
    0014   20 Bitstring   44 DUBSA515 (0)   Words 5-15 for ESA/390 guest
    0014   20 Bitstring    8 *              Reserved for IBM use
    001C   28 Signed       4 DUPRGM         For use by programming
    0020   32 Signed       4 DUBSAADR       BSA addr mode & return addr First
                                            bit of the DUBSAADR field
              1... ....      DUBSAADM       X'80' BSA address mode bit
    0024   36 Signed       4 DUBSAPSW       PSW info for BSA instruction
    0028   40 Bitstring    4 *              Reserved for IBM use
    002C   44 Address      4 DUTRPCTL       Trap-Control-Block address
    0030   48 Bitstring   16 *              Reserved for IBM use
              00000040       DUCTLEN        *-DUCT Length in bytes
              00000008       DUCTSIZE       (*-DUCT+7)/8 Length in
                                            doublewords
         Redefinition of DUBSAPSW
    0024   36 Bitstring    2 DUBSAPKM       PSW key mask
    0026   38 Bitstring    1 *              Reserved for IBM use
    0027   39 Bitstring    1 DUBSAPS1       Misc PSW stuff
              1111 ....      DUBSAPSK       X'F0' PSW key
              .... 1...      DUBSARA        X'08' Reduced authority bit
              .... ...1      DUBSAPSB       X'01' Problem state bit

#### DUCT Storage Layout

    *** DUCT - Dispatchable Unit Control Table
    *
    *     +---------------------------+---------------------------+
    *   0 |          DUIBM1           |          DUIBM2           |
    *     +---------------------------+---------------------------+
    *   8 |///////////////////////////|          DUIBM4           |
    *     +---------------------------+---------------------------+
    *  10 |          DUALD            |///////////////////////////|
    *     +---------------------------+---------------------------+
    *  18 |///////////////////////////|          DUPRGM           |
    *     +---------------------------+---------------------------+
    *  20 |         DUBSAADR          |         DUBSAPSW          |
    *     +---------------------------+---------------------------+
    *  28 |///////////////////////////|         DUTRPCTL          |
    *     +---------------------------+---------------------------+
    *  30 |///////////////////////////////////////////////////////|
    *     |///////////////////////////////////////////////////////|
    *     +-------------------------------------------------------+
    *  40
    *
    *** DUCT - Dispatchable Unit Control Table

    *** Overlay for DUBSAPSW in DUCT
    *
    *                                 +-------------+------+------+
    *  20 ...                      24 |  DUBSAPKM   |//////|:SAPS1|
    *                                 +-------------+------+------+
    *  28
    *
    *** Overlay for DUBSAPSW in DUCT

#### DUCT Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    DUALD          0010
    DUBSAADM       0020 80
    DUBSAADR       0020
    DUBSAPKM       0024
    DUBSAPSB       0027 01
    DUBSAPSK       0027 F0
    DUBSAPSW       0024
    DUBSAPS1       0027
    DUBSARA        0027 08
    DUBSA515       0014
    DUCTLEN        0030 00000040
    DUCTSIZE       0030 00000008
    DUIBM1         0000
    DUIBM2         0004
    DUIBM4         000C
    DUPRGM         001C
    DUTRPCTL       002C

This information is based on z/VM V4R3.0. Last updated on 30 Apr 2002 at 16:16:07 EDT.
Copyright IBM Corporation, 1990, 2002