SEG37 - 32-bit CP - V4R4.0

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

#### SEG37

Prolog

Control Block Contents
SEG37 DSECT

Storage Layout

Cross Reference (Contains links to field and bit definitions)

#### SEG37 Prolog

     NAME       : HCPSEG37
     DESCRIPTION: Segment Table Entry for 370
     DSECT      : SEG37
     Function   : The following maps the segment table entry in the
                  System/370 architecture.
                  The format of the 370 segment table entry is
                  architected and cannot be changed in any way
                  which violates the architecture.

#### SEG37 Control Block Content

#### SEG37 DSECT

    Hex   Dec Type/Val   Lng Label (dup)    Comments
    ---- ---- --------- ---- -------------- --------
    0000    0 Structure      SEG37          Segment Table Entry for 370
    0000    0 Signed       4 SEG3ENTR (0)   System/370 Segment Table Entry
    0000    0 Bitstring    1 *              Page table length in left nibble
                                            and right nibble must be 0.
    0001    1 Bitstring    1 *              Part of page table address
    0002    2 Bitstring    1 *              Part of page table address
    0003    3 Bitstring    1 SEG370ST       Segment table entry status for
                                            370 non-extended architecture.
                                            Leftmost 5 bits comprise part of
                                            the page table address. Rightmost
                                            3 bits are the status.
              .... .1..      SEG370PR       X'04' Segment is write protected
              .... ..1.      SEG370CO       X'02' Segment is a common segment
              .... ...1      SEG370IV       X'01' Segment is invalid
              00000004       SEG3LENT       *-SEG3ENTR Length of one 370 STE
    0004    4 Signed       4 SEG3NEXT (0)   Next 370 STE
              00FFFFF8       SEG3PTOM       X'00FFFFF8' Isolate page-table
                                            origin in S/370 architecture STE
              .... ...1      SEG3INVM       X'00000001' Isolate
                                            segment-invalid bit in S/370
                                            architecture STE
              .... ..1.      SEG3COMM       X'00000002' Isolate
                                            common-segment bit in S/370
                                            architecture STE
              .... .1..      SEG3PROM       X'00000004' Isolate
                                            segment-protection bit in S/370
                                            architecture STE
              .... ....      SEG3PTLM       X'F0000000' Isolate page-table
                                            length in S/370 architecture STE
              .... ...1      SEG3RSVM       X'0F000001' Reserved bits, must
                                            be 0 in any valid S/370
                                            architecture STE
         END OF DEFINITION

#### SEG37 Storage Layout

    *** SEG37 - Segment Table Entry for 370
    *
    *     +------+------+------+------+
    *   0 |//////|//////|//////|:370ST|
    *     +------+------+------+------+
    *
    *** SEG37 - Segment Table Entry for 370

#### SEG37 Cross Reference

    Symbol         Dspl Value
    -------------- ---- -----
    SEG3COMM       0004 02
    SEG3ENTR       0000
    SEG3INVM       0004 01
    SEG3LENT       0003 00000004
    SEG3NEXT       0004
    SEG3PROM       0004 04
    SEG3PTLM       0004 00
    SEG3PTOM       0004 00FFFFF8
    SEG3RSVM       0004 01
    SEG370CO       0003 02
    SEG370IV       0003 01
    SEG370PR       0003 04
    SEG370ST       0003

This information is based on z/VM V4R4.0. Last updated on 29 Jul 2003 at 16:15:45 EDT.
Copyright IBM Corporation, 1990, 2003