NAME       : HCPSTD
 DESCRIPTION: Architected version of the ESA/390
              segment-table designation.
 DSECT      : STD
 FUNCTION   : This DSECT maps the ESA/390 segment-table
              designation. The format of a segment-table
              designation is architected, and described in the
              Principles of Operation.
 LOCATED BY : CR1      is the STD for the primary address space.
              CR7      is the STD for the secondary address space.
              CR13     is the STD for the home address space.
              ASTSTD   in an ASTE.
              VMDPSTD  is the STD for a virtual CPU's current
              primary address space.
              PFXSXSTD is the STD for the system-execution space.
 CREATED BY : HCPASMCR when an address space is created.
              HCPSSMCR when the system-execution address space is
              created.
              HCPFMUSG when the full track cache address space
              is created.
              HCPHDTMA when an address space is expanded.
              HCPHDTNL when an address space is compressed.
 DELETED BY : HCPASMDS when the address space is destroyed.
 RELOCATION CONSIDERATIONS : None

 STD DSECT
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Hex   Dec Type/Val   Lng Label (dup)    Comments
---- ---- --------- ---- -------------- --------
0000    0 Structure      STD            Architected version of the ESA/390
      ESA/390 mode STD - 4 bytes, 32 bits
0000    0 Signed       4 STDES (0)      Entire STD
          .... ....      STDSWEM        X'80000000' STDSWEM Isolate
                                        space-switch-event bit
          000STDES       STDSTOM        X'7FFFF000' STDSTOM Isolate
                                        segment-table origin
          000STDES       STDPSM         X'00000100' STDPSM Isolate
                                        private-space bit
          1... ....      STDSAEM        X'00000080' STDSAEM Isolate
                                        storage-alteration-event bit.
          .111 1111      STDSTLM        X'0000007F' STDSTLM Isolate
                                        segment-table length
          .1.. ....      STDSTUNT       64 STDSTUNT Number of bytes in a
                                        "segment- table unit", the number
                                        of bytes in the smallest
                                        variation of the size of a
                                        segment table.
          .... ...1      STDSTL01       X'01' STDSTL01 2 64-byte blocks
                                        (to address 32M)
          ..11 1111      STDSTL3F       X'3F' STDSTL3F 64 64-byte blocks
                                        (to address 1024M).
          .1.. ....      STDSTL40       X'40' STDSTL40 65 64-byte blocks
                                        (to address 1040M), also, the
                                        number of 64-byte blocks in one
                                        4K page of segment table entries.
          .111 1111      STDSTL7F       X'7F' STDSTL7F 128 64-byte blocks
                                        (to address 2048M).
          .... .11.      STDSTUNS       6 STDSTUNS Number of bits to
                                        shift left in order to multiply
                                        by STDSTUNT. Also, number of bits
                                        to shift to convert between STE
                                        offset and corresponding STL
                                        value.
          ...1 1...      STDSXSTL       20+4 STDSXSTL 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.
          ...1 .1.1      STDSXDWS       STDSXSTL-3 STDSXDWS Bits to shift
                                        to convert between an isolated
                                        segment index (or number of
                                        addressable bytes) and
                                        doublewords of segment table
                                        space required.
          .... ..11      STDDWSTL       3 STDDWSTL Bits to shift to
                                        convert between STL units and
                                        segment table length in
                                        doublewords.
          .... .11.      STDBYSTL       6 STDBYSTL Bits to shift to
                                        convert between STL units and
                                        segment table length in bytes.
          ...1 ..1.      STDSXDSP       20-2 STDSXDSP Bits to shift right
                                        an isolated segment index to
                                        obtain the displacement into the
                                        segment table of the applicable
                                        STE.
0000    0 Bitstring    1 STD0           STD, byte 0
          1... ....      STDSWE         X'80' STDSWE Space-switch event
                                        bit. When set, space-switch event
                                        program interruptions are
                                        recognized when space switches
                                        occur.
0001    1 Bitstring    1 STD1           STD, byte 1
0002    2 Bitstring    1 STD2           STD, byte 2
          .... ..1.      STDSSGRP       X'02' STDSSGRP Subspace-Group
                                        bit. When set, indicates that the
                                        address space specified by the
                                        STD is part of a subspace group.
          .... ...1      STDPRIVS       X'01' STDPRIVS Private-space bit.
                                        When set, prefixing, low-address
                                        protection, and fetch- protection
                                        override to not apply to DAT
                                        references.
0003    3 Bitstring    1 STD3           STD, byte 3
          1... ....      STDSAE         X'80' STDSAE
                                        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.
          00000004       STDSLEN        *-STDES Length in bytes of a STD.
          00000001       STDSSIZE       (STDSLEN+7)/8 Size in doublewords
                                        of a STD.
      The following maps the segment-table designation in the
      System/370 architecture.
          .... ....      STD3STLM       X'FF000000' Isolate segment-table
                                        length
          00FFFFC0       STD3STOM       X'00FFFFC0' Isolate segment-table
                                        origin
          .... ...1      STD3SWEM       X'00000001' Isolate
                                        space-switch-event bit

          
*** STD - Architected version of the ESA/390
*
*     +------+------+------+------+
*   0 |STD0  |STD1  |STD2  |STD3  | 4
*     +------+------+------+------+
*
*** STD - Architected version of the ESA/390

 
Symbol         Dspl Value
-------------- ---- -----
STDBYSTL       0000 06
STDDWSTL       0000 03
STDES          0000
STDPRIVS       0002 01
STDPSM         0000 000STDES
STDSAE         0003 80
STDSAEM        0000 80
STDSLEN        0003 00000004
STDSSGRP       0002 02
STDSSIZE       0003 00000001
STDSTLM        0000 7F
STDSTL01       0000 01
STDSTL3F       0000 3F
STDSTL40       0000 40
STDSTL7F       0000 7F
STDSTOM        0000 000STDES
STDSTUNS       0000 06
STDSTUNT       0000 40
STDSWE         0000 80
STDSWEM        0000 00
STDSXDSP       0000 12
STDSXDWS       0000 15
STDSXSTL       0000 18
STD0           0000
STD1           0001
STD2           0002
STD3           0003
STD3STLM       0003 00
STD3STOM       0003 00FFFFC0
STD3SWEM       0003 01