Displaying and modifying the value of assembler variables or storage

To list the contents of a single variable, move the cursor to an occurrence of the variable name in the Source window and press PF4 (LIST). The value is displayed in the Log window. This is equivalent to entering LIST variable on the command line.

For example, run the SUBXMP program to the statement labeled  CALL1  by entering AT 70 ; GO ; on the z/OS® Debugger command line. Scroll up until you see line 67. Move the cursor over COUNTER and press PF4 (LIST). The following appears in the Log window:

LIST ( COUNTER )
COUNTER = 0

To modify the value of COUNTER to 1, type over the COUNTER = 0 line with COUNTER = 1, press Enter to put it on the command line, and press Enter again to issue the command.

To list the contents of the 16 bytes of storage 2 bytes past the address contained in register R0, type the command LIST STORAGE(R0->+2,16) on the command line and press Enter. The contents of the specified storage are displayed in the Log window.

LIST STORAGE( R0 -> + 2 , 16 )
000C321E  C8859393 96408699 969440A3 888540A2   *Hello from the s*

To modify the first two bytes of this storage to X'C182', type the command R0->+2 <2> = X'C182'; on the command line and press Enter to issue the command.

Now step into the call to DISPARM by pressing PF2 (STEP) and step until the line labeled CALL2 is reached. To view the attributes of variable COUNTER, issue the z/OS Debugger command:

DESCRIBE ATTRIBUTES COUNTER

The result in the Log window is:

ATTRIBUTES for COUNTER
   Its address is  1B0E2150 and its length is 4
   DS F