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

#### STDG

Prolog

Control Block Contents
STDG DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### STDG Control Block Content

#### STDG DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      STDG           Architected version of the z/Arch
    0000    0 Dbl-Word     8 STDGES (0)     Entire STD
          64-bit mask  X'FFFFFFFFFFFFF000'
              00000AF0       STDGSTOM       PFXGPFRA Isolate STO, 64-bit mask
              00FFF000       STDGSTOML      X'FFFFF000' Isolate STO, 32-bit
                                            mask
          64-bit mask  X'0000000000000200'
          32-bit high  X'00000000'
              00000200       STDGSSGM       X'00000200' Isolate
                                            subspace-group control bit
          64-bit mask  X'0000000000000100'
          32-bit high  X'00000000'
              00000100       STDGPSM        X'00000100' Isolate private-space
                                            bit
          64-bit mask  X'0000000000000080'
          32-bit high  X'00000000'
              1... ....      STDGSAEM       X'00000080' Isolate
                                            storage-alteration event bit
          64-bit mask  X'0000000000000040'
          32-bit high  X'00000000'
              .1.. ....      STDGSWEM       X'00000040' Isolate space-switch-
                                            event bit
          64-bit mask  X'0000000000000020'
          32-bit high  X'00000000'
              ..1. ....      STDGRBM        X'00000020' Isolate real-space
                                            control bit (zero in zArch STD)
          64-bit mask  X'000000000000000C'
          32-bit high  X'00000000'
              .... 11..      STDGDTBM       X'0000000C' Isolate designation
                                            type control bits (must be B'00'
                                            in a z/Arch STD)
          64-bit mask  X'0000000000000003'
          32-bit high  X'00000000'
              .... ..11      STDGSTLM       X'00000003' Isolate segment-table
                                            length
              00001000       STDGSTUNT      4096 Number of bytes in a
                                            "segment- table unit", the number
                                            of bytes in the smallest
                                            variation of the size of a
                                            segment table.
              .... ....      STDGSTL0       X'00' 1 4096-byte block (to
                                            address up to 512M)
              .... ..11      STDGSTLF       X'03' 4 4096-byte blocks (to
                                            address up to 2048M == 2G)
              0000000C       STDGSTUNS      12 Number of bits to shift left
                                            in order to multiply by
                                            STDGSTUNT. Also, number of bits
                                            to shift to convert between STE
                                            offset and corresponding STL
                                            value.
              0000001D       STDGSXSTL      20+9 Bits to shift to convert
                                            between an isolated segment index
                                            and the corresponding segment-
                                            table length. Also used to
                                            convert between STL units and
                                            addressable bytes.
              0000001A       STDGSXDWS      STDGSXSTL-3 Bits to shift to
                                            convert between an isolated
                                            segment index (or number of
                                            addressable bytes) and
                                            doublewords of segment table
                                            space required.
              00000009       STDGDWSTL      9 Bits to shift to convert
                                            between STL units and segment
                                            table length in doublewords.
              0000000C       STDGBYSTL      12 Bits to shift to convert
                                            between STL units and segment
                                            table length in bytes.
              00000011       STDGSXDSP      20-3 Bits to shift right an
                                            isolated segment index to obtain
                                            the displacement into the segment
                                            table of the applicable STE.
    0000    0 Signed       4 *              Bytes 0-3 of STDG
    0004    4 Signed       2 *              Bytes 4-5 of STDG
    0006    6 Bitstring    1 STDG6          STDG, byte 6
              1111 ....      STDG6STO       X'F0' Reserved, nibble part of
                                            STO
              .... ..1.      STDGSSGRP      X'02' Subspace-Group bit. When
                                            set, indicates that the address
                                            space specified by the STDG is
                                            part of a subspace group.
              .... ...1      STDGPRIVS      X'01' Private-space bit. When
                                            set, prefixing, low-address
                                            protection, and fetch- protection
                                            override to not apply to DAT
                                            references.
    0007    7 Bitstring    1 STDG7          STDG, byte 7
              1... ....      STDGSAE        X'80' Storage-alteration-event
                                            bit. When set, storage-alteration
                                            PER events in this address space
                                            are enabled via the
                                            storage-alteration-space control
                                            bit of CR9.
              .1.. ....      STDGSWE        X'40' Space-switch event bit.
                                            When set, space-switch event
                                            program interruptions are
                                            recognized when space switches
                                            occur.
    0008    8 Bitstring    1 STDGRBIT       Real-space control bit (R bit)
                                            (Must be zero in a z/Arch STDG)
              .... 11..      STDGTBIT       X'0C' Designation type bits (DT
                                            bits) (must be B'00' in zArch
                                            STDG)
              .... ..11      STDGSTLX       X'03' Segment-table length field
              00000009       STDGSLEN       *-STDGES Length in bytes of STDG
              00000002       STDGSSIZE      (STDGSLEN+7)/8 Size in DW of STDG

#### STDG Storage Layout

    *** STDG - Architected version of the z/Arch
    *
    *     +---------------------------+-------------+------+------+
    *   0 |///////////////////////////|/////////////|STDG6 |STDG7 |
    *     +------+--------------------+-------------+------+------+
    *   8 |:GRBIT| 9
    *     +------+
    *
    *** STDG - Architected version of the z/Arch

#### STDG Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    STDGBYSTL      0000 0000000C
    STDGDTBM       0000 0C
    STDGDWSTL      0000 00000009
    STDGES         0000
    STDGPRIVS      0006 01
    STDGPSM        0000 00000100
    STDGRBIT       0008
    STDGRBM        0000 20
    STDGSAE        0007 80
    STDGSAEM       0000 80
    STDGSLEN       0008 00000009
    STDGSSGM       0000 00000200
    STDGSSGRP      0006 02
    STDGSSIZE      0008 00000002
    STDGSTLF       0000 03
    STDGSTLM       0000 03
    STDGSTLX       0008 03
    STDGSTL0       0000 00
    STDGSTOM       0000 00000AF0
    STDGSTOML      0000 00FFF000
    STDGSTUNS      0000 0000000C
    STDGSTUNT      0000 00001000
    STDGSWE        0007 40
    STDGSWEM       0000 40
    STDGSXDSP      0000 00000011
    STDGSXDWS      0000 0000001A
    STDGSXSTL      0000 0000001D
    STDGTBIT       0008 0C
    STDG6          0006
    STDG6STO       0006 F0
    STDG7          0007

This information is based on z/VM V5R2.0. Last updated on 12 Apr 2006 at 17:28:03 EDT.
Copyright IBM Corporation, 1990, 2005