assemblymainframezoss390x

HLASM on z/OS Issues errors about Invalid OpCode

I'm trying to add two numbers and subtract two numbers but when I compile my code it says 'invalid op-code' (I'm using assist (IBM))

MAIN               CSECT
                   USING MAIN,15
->invalid op-code  NUM1 DC F'67'
->invalid op-code  NUM2 DC F'203'
                   L    0,NUM1
                   L    1,NUM2
                   AR   0,1
                   L    2,NUM1
                   L    3,NUM2
                   SR   2,3
                   XDUMP
                   END MAIN
Solution

  • A few things. First, the placement of the data items is important as it will be incorporated in with the code list. Unlike higher level languages where declarations of data types are organized automatically.

    Second, you are declaring the data items incorrectly. The name should start in column 1 with the data type DC next and then followed by the data. This will simply include the data inline with the other code which will cause your program to fail with an abend S0C1.

    Here is an suggested way to declare the data

    Columns    
0        1         2         3         4
1234567890123456789012345678901234567890

MAIN     CSECT  
         USING MAIN,15  
         L    0,NUM1
         L    1,NUM2
         AR   0,1
         L    2,NUM1
         L    3,NUM2
         SR   2,3
         XDUMP
NUM1     DC   F'67'
NUM2     DC   F'203'
         END  MAIN

    Moving the data out of the code path and putting its name in the right column communicates that your data label is not an op-code.