ISEQ instruction
- sequence_symbol
- Is a sequence symbol.
- left
- Specifies the first column of the field to be sequence-checked. If specified, left must be a decimal self-defining term with value 1 - 80.
- right
- Specifies the rightmost column of the field to be sequence checked. If specified, right must be a decimal self-defining term with value 1 - 80, and must be greater than or equal to left.
If left and right are omitted, sequence checking is ended. Sequence checking can be restarted with another ISEQ statement. An ISEQ statement that is used to end sequence checking is itself sequence-checked.
The assembler begins sequence checking with the first statement line following the ISEQ instruction. The assembler also checks continuation lines.
Sequence numbers on adjacent statements or lines are compared according to the 8 bit internal EBCDIC collating sequence. When the sequence number on one line is not greater than the sequence number on the preceding line, a sequence error is flagged, and a warning message is issued, but the assembly is not ended.
If the sequence field in the preceding line is spaces, the assembler uses the last preceding line with a non-space sequence field to make its comparison.
- Statements inserted by a COPY instruction
- Statements generated from model statements inside macro definitions or from model statements in open code (statement generation is discussed in detail in How to specify macro definitions)
- Statements in library macro definitions