STDG DSECT
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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' STDG6STO Reserved, nibble
                                        part of STO
          .... ..1.      STDGSSGRP      X'02' STDGSSGRP Subspace-Group
                                        bit. When set, indicates that the
                                        address space specified by the
                                        STDG is part of a subspace group.
          .... ...1      STDGPRIVS      X'01' STDGPRIVS 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' STDGSAE
                                        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' STDGSWE 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 - Architected version of the z/Arch
*
*     +---------------------------+-------------+------+------+
*   0 |///////////////////////////|/////////////|STDG6 |STDG7 |
*     +------+--------------------+-------------+------+------+
*   8 |:GRBIT| 9
*     +------+
*
*** STDG - Architected version of the z/Arch

 
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