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.
 RELOCATION CONSIDERATIONS : None

 

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' SEG370PR Segment is write
                                        protected
          .... ..1.      SEG370CO       X'02' SEG370CO Segment is a
                                        common segment
          .... ...1      SEG370IV       X'01' SEG370IV Segment is invalid
          00000004       SEG3LENT       *-SEG3ENTR Length of one 370 STE
0004    4 Signed       4 SEG3NEXT (0)   Next 370 STE
          SEG3NEXT       SEG3PTOM       X'00FFFFF8' SEG3PTOM Isolate
                                        page-table origin in S/370
                                        architecture STE
          .... ...1      SEG3INVM       X'00000001' SEG3INVM Isolate
                                        segment-invalid bit in S/370
                                        architecture STE
          .... ..1.      SEG3COMM       X'00000002' SEG3COMM Isolate
                                        common-segment bit in S/370
                                        architecture STE
          .... .1..      SEG3PROM       X'00000004' SEG3PROM Isolate
                                        segment-protection bit in S/370
                                        architecture STE
          .... ....      SEG3PTLM       X'F0000000' SEG3PTLM Isolate
                                        page-table length in S/370
                                        architecture STE
          .... ...1      SEG3RSVM       X'0F000001' SEG3RSVM 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 SEG3NEXT
SEG3RSVM       0004 01
SEG370CO       0003 02
SEG370IV       0003 01
SEG370PR       0003 04
SEG370ST       0003

This information is based on z/VM V6R2.0. Last updated on 21 Nov 2011 at 11:20:21 EDT.
Copyright IBM Corporation, 1990, 2011