STD Back to Index page
Control Block Contents 
Storage Layout 
Cross Reference (Contains links to field and bit definitions)
Programming Interface Information:
This page documents intended Programming Interfaces that
allow the customer to write programs to obtain the services of z/VM.

  STD Prolog Top of page
 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
              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.
  STD Control Block Content Top of page

 STD DSECT Top of page
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 Storage Layout Top of page
*** STD - Architected version of the ESA/390
*     +------+------+------+------+
*   0 |STD0  |STD1  |STD2  |STD3  | 4
*     +------+------+------+------+
*** STD - Architected version of the ESA/390
  STD Cross Reference Top of page
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
This information is based on z/VM 6.3.0 Last updated on 22 May 2013 at 13:56:36 EDT.
Copyright IBM Corporation, 1990, 2013