Mapping storage areas using DSECT information

By using the DSECT command from within the interactive report, storage areas can be mapped based on PDS or PDSE data set members containing assembler macro or DSECT copybooks.

The DSECT command (see DSECT for syntax), can be entered from the command line of any display, or via PF key assignment. By default, the DSECT command is assigned to PF4.

When invoked, you are shown a popup window similar to the following:

Figure 1. Sample Storage DSECT Mapping Entry display

  File  View  Services  Help
┌─────────────────────────── Storage DSECT Mapping ───────────────────────────┐
│                                                                             │
│ Enter the name of the Dsect in the Dsect Name field to be used to map the   │
│ storage address provided in the Address field. Press PF4 to display a list  │
│ of all available Dsects.  Optionally a specific Dsect can be used by        │
│ supplying a Dataset and Member name in the DSN field.  In this case if a    │
│ Dsect name is not provided it will be made equal to the member name.        │
│                                                                             │
│ Address                                                                     │
│ Dsect Name                                                                  │
│ DSN  . . .                                                                  │
│                                                                             │
│                                                                             │
│  F1=Help     F3=Exit    F12=Cancel                                          │
└─────────────────────────────────────────────────────────────────────────────┘
  First Operand Address . . : 0002A120 (3808 bytes of storage addressable)
  First Operand Length. . . : 8
  First Operand Storage . . : 00000000 0986888C   *.....fh.*
  Second Operand Address. . : 0002A110 (3824 bytes of storage addressable)
  Second Operand Length . . : 4
  Second Operand Storage. . : C1C2C3CF   *ABC.*
 F1=Help      F3=Exit      F5=RptFind   F6=Actions   F7=Up        F8=Down
F10=Left     F11=Right

Note: If the DSECT command is issued while the cursor is on an address point-and-shoot field. then the popup display address is automatically initialized to that address.

You can now supply the start address (if not already filled in), and the name of the DSECT to use when mapping the storage area. The Address field is 64-bit enabled. For details, see Specifying 64-bit addresses.

The name of the DSECT can be provided in one of two ways:

Just the DSECT name can be entered, in which case the IDIDSECT concatenation is searched for a match (see IDIDSECT concatenation for details). If multiple occurrences of the requested DSECT exist in the IDIDSECT concatenation, then press PF4 and select the appropriate one from the resulting list of all available DSECTs. A DSECT is selected from the list using an 'S', or it can be Edited by entering an 'E'.
The data set and member name where the specified DSECT is stored can be supplied. If a DSECT name is not provided, then it defaults to be the same as the PDS or PDSE member name.

Once a valid storage address and DSECT name have been specified, the storage is mapped and displayed, similar to the following example:

Figure 2. Sample Storage DSECT Mapping Map display

   File  View  Services  Help
 ───────────────────────────────────────────────────────────────────────────────
 Dsect mapping for DFHCSADS at address 4de20                    Line 1 Col 1 80
 Command ===> ________________________________________________ Scroll ===> CSR 
 
 CICS DUMP: SYSTEM=QXPM2C61 CODE=ASRA     ID=      MVS2     2019/06/25 13:47:55

 0004DE20 +0000                                     DSECT DFHCSADS
                                                    DFHCSABA EQU   *
 0004DE20 +0000 00000248 0000D0A0 17EB4D00 983C1ECE
                80BF4DA8 80800000 18685160 18642330
                000003FD 18973FB8 00000BAF 00000000
                983C1A40 18973000 18685160 18684B70
                00051D80 17F90680                   CSAOSRSA DS    18F
                                                    CSASOSI  DS    0B
 0004DE68 +0072 00                                  CSASSI1  DS    B
                                                    CSAFPURG EQU   X'80'
                                                    CSAFTCAB EQU   X'40'
                                                    CSASDTRN EQU   X'20'
                                                    CSACSDOP EQU   X'02'
                                                    CSASOSON EQU   X'01'
                                                    CSAKCMI  DS    0B
 0004DE69 +0073 10                                  CSASSI2  DS    B
  F1=Help      F3=Exit      F5=RptFind   F6=Actions   F7=Up        F8=Down
 F10=Left     F11=Right

Scroll up/down or right/left as needed to display more DSECT information.

Press PF3 to return from the Storage DSECT Mapping Map display.

IDISYSLB concatenation

The DSECT command and IDIPDSCU utility both use, internally, the assembler to generate ADATA which is then used to determine field names and offsets. The SYSLIB DD, used by the assembler, is dynamically allocated to the same data set as the source DSECT. However this may be insufficient where, for example, an assembler macro is used to generate the DSECT and that macro does not exist in the DSECT data set. To allow for this situation additional SYSLIB data sets can be specified by allocating them to an IDISYSLB DD.

For example, data set MY.DSECTS has 1 member in it, CICSSIT, for generating the CICS DFHSIT DSECT:


    000001 * GENERATE THE CICS DFHSIT DSECT
    000002          DFHSIT TYPE=DSECT      
    000003          END

Using this data set or member in the DSECT command or IDIPDSCU utility will not generate a usable DSECT as the DFHSIT macro will not be resolved. Therefore, the IDISYSLB DD can be used. For example:


    //UTIL1    EXEC PGM=IDIPDSCU,PARM=('MY.DSECTS')            
    //SYSPRINT DD   SYSOUT=*                                   
    //SYSPUNCH DD   SYSOUT=*                                   
    //IDISYSLB   DD DISP=SHR,DSN=CICS.TS61.CICS.SDFHMAC

When using the DSECT command during interactive reanalysis, or when using IDIPDSCU in ISPF, use the TSO ALLOCATE command:

ALLOCATE FILE(IDISYSLB) DS('CICS.TS61.CICS.SDFHMAC') SHR