HLASM Language Reference

| For executable sections, the location values that appear in the listings depend on
| the THREAD option:
| If you specify NOTHREAD, the location counter values for each section,
| element, or part restart at 0, except possibly those associated with a first
| section initiated by a START instruction with a nonzero address.
| If you specify THREAD, location counter values do not restart at 0 for each
| subsequent section, element, or part. They continue, after suitable alignment,
| from the end of the previous section, element, or part.
For reference control sections, the location values that appear in the listings always
start from 0.
You can continue a control section, element, or part that has been discontinued
and, thereby, intersperse code sequences from different control sections, elements,
or parts. Note that the location values that appear in the listings for such
discontiguous sequences are divided into segments that follow from the end of one
segment to the beginning of the subsequent segment.
The location values, listed for the next defined control section, element, or part,
begin after the last location value assigned to the preceding such item.
On VSE, or when you specify the NOGOFF assembler option on MVS and CMS,
the maximum value of the location counter and the maximum length of a control
| section is 2 24 −1, or X'FFFFFF' bytes. If LIST(133) is in force, then the high-order
| is shown as zero.
When you specify the GOFF assembler option, the maximum value of
the location counter and the maximum length of an element or part is 2 31 −1, or
X'7FFFFFFF' bytes.
Location Counter and Length Limits
| The assembler also maintains a length counter for each individually relocatable
| component of the program: executable and reference control sections, elements,
| and parts.
| If any location counter overflows its maximum value, High Level Assembler issues
| the severe error message:
| ASMA39S Location counter error
| and continues assembling with the location counter value “wrapping” around to
| zero.
| The length of a section, element, or part cannot exceed the maximum allowed
| length described above. If the length counter reaches this maximum value, it stays
| fixed at that value without an error condition or error message. Exceeding the
| length counter will cause overflow of the location counter, producing the ASMA39S
| message.
| The location counter setting is relative to the beginning of the location it represents,
| and the length counter represents the cumulative length of the control section. This
| means that the length counter is nearly always greater than the location counter,
| and can exceed its maximum value before the location counter. Even if the
| location counter overflows, the length counter value may be correct, and
62 HLASM V1R5 Language Reference