Basic Demo Session › Detect and Prevent an Abend

Detect and Prevent an Abend

The next screen you see is not displayed by ASMDEMO. It is a diagnostic screen, called a breakpoint display, produced by the application.

CA InterTest for CICS Release 9.1.00  ‑ PROTSYM FILE SOURCE LISTING BREAKPOINT 
COMMAND ===>                                                                   
Program= ASMDEMO  Option #       Stmt #        Displacement=        Margin= 01
                                        Search=                                
‑‑‑‑‑‑‑‑‑+‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑‑
     LOC  OBJECT CODE    ADDR1 ADDR2  STMT        SOURCE STATEMENT             
 _ 00016A 4050 D1B0            001B0  1355          STH   R5,MSGLEN            
 A 00016E FA20 D189 4AC0 00189 02AC0   ==>          AP    TASKNUM,=P'1'        
     ==>                                                                       
     ==> ASRA ABEND (0C7) detected and prevented. Caused by invalid decimal    
     ==> arithmetic data format.                                             
     ==>                                                                       
     ==>      Press PF1 for a detailed description.                          
     ==>                                                                       
 _ 000174 F920 D189 4AC1 00189 02AC1  1357          CP    TASKNUM,=P'2'        
 _ 00017A 4720 2300            00300  1358          BH    ENDMSG               
 _ 00017E F920 D189 4AC0 00189 02AC0  1359          CP    TASKNUM,=P'1'        
 _ 000184 4780 2256            00256  1360          BE    SENDSCR4             
 _ 000188 47F0 2300            00300  1361          B     ENDMSG               
 _ 00018C                             1363 RETURN   DS    0H                   
                                      1364 *        EXEC CICS SEND FROM(OUTMSG 
                                      1365          DFHECALL =X'04043000080000 
   00018C 4110 D068            00068                      ),(FB_2,OUTLEN)      
                                      1381 *        EXEC CICS SEND FROM(SCREE

Look at the highlighted area. The application has highlighted an Add Packed (AP) instruction and displayed a message below it.

Execution of that AP instruction triggered an ASRA. the application prevented the abend and then displayed the diagnostic screen you are currently viewing.

When the application stops program execution, we say that it halts the program at a breakpoint. It does this automatically, as in the case shown in the previous screen, or halts a program at a breakpoint set by you, the programmer. The A to the far left of the AP instruction indicates that the current halt in program execution is an Automatic breakpoint; not one set by you.

Now look at the highlighted message. It explains that the ASRA was caused by improperly formatted data. Which data? Since the instruction that triggered the ASRA was adding a packed 1 (=P'1') to the data in TASKNUM, it is likely that TASKNUM contains improperly formatted data.

The application prevented ASMDEMO from abending and identified the problem.

Next, you will:

1. Determine the cause of the error.
2. Dynamically correct the error by changing the value in TASKNUM.