Message descriptions

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Each message entry for assembly error diagnostic messages and assembly abnormal termination messages has the following five sections:
  • Message Number and Text
  • Explanation of Message
  • System Action
  • Programmer Response
  • Severity Code
Each message entry for ASMAHL command error messages has up to five of the following sections:
  • Message Number and Text
  • Explanation of Message
  • Supplemental Information
  • System Action
  • Programmer Response
Message Number and Text
Only the message number and the major fixed portion of the message text are included in the message description. Any abbreviations in actual message text are described under the message explanation section. Unused message numbers account for the gaps in the message number sequence. No messages are defined for numbers which are not included in this section (for example, ASMA222).
Explanation of Message
For some messages there is more than one explanation, as different sections of the assembler can generate the same message. Several assembler termination messages have identical explanations.
Supplemental Information
For ASMAHL command error messages, the supplemental information describes the possible contents of the variables in the message text.
System Action
This section describes how the assembler handles statements with errors. Some actions include:
  • A machine instruction assembles as all zeros.
  • An assembler instruction is normally ignored; it is printed but has no effect on the assembly. Many assembler instructions, however, are partially processed or processed with a default value. For some instructions, the operands preceding the operand in error, or every operand except the operand in error, is processed. For example, if one of several operands on a DROP statement is a symbol that cannot be evaluated to a register number, only that operand is ignored. All the correctly specified registers are processed correctly.
  • For some assembler statements, especially macro prototype and conditional assembly statements, the operand or term in error is given a default value. Thus the statement assembles completely, but probably causes incorrect results if the program is run.

For ASMAHL command error messages, this section describes the command return code and the status of the system after the error.

Programmer Response
Many errors have specific or probable causes. In such a case, the Programmer Response section gives specific steps for fixing the error. Most messages, however, have too many possible causes to list (from keying errors to wrong use of the statement). The Programmer Response section for these error messages does not give specific directions. The cause of most such errors can be determined from the message text and the explanation.
Severity Code
The level of severity code indicates how critical the error might be. The severity codes and their meanings are described in Message code format.

ASMAHL messages (those messages starting with ASMACMS) have a severity code letter of E. The associated return code is shown in the System Action for each message. An ASMAHL message that causes the assembly to terminate generates a return code greater than 20.

The severity code is used to determine the return code issued by the assembler when it returns control to the operating system. The IBM-supplied cataloged procedures (for z/OS®) include a COND parameter on the linkage edit and run steps. The COND parameter prevents the running of these steps if the return code from the assembler is greater than 8. Thus errors with a severity code of S prevent the assembled program from linkage editing or running. Errors with a severity code of E, or lower, in the message do not prevent the assembled program from linkage editing or running.