HLASM Language Reference

Addressing
| reassembling with the NOTHREAD option may avoid the location counter overflow
| condition.
Use of Multiple Location Counters
High Level Assembler lets you use multiple location counters for each individual
control section. Use the LOCTR instruction (see “LOCTR Instruction” on page 191)
to assign different location counters to different parts of a control section. The
assembler then rearranges and assembles the coding together, according to the
different location counters you have specified: all coding using the first location
counter is assembled together, then the coding using the second location counter is
assembled together, and so forth.
An example of the use of multiple location counters is shown in Figure 19. In the
example, executable instructions and data areas have been interspersed
throughout the coding in their logical sequence, each group of instructions
preceded by a LOCTR instruction identifying the location counter under which it is
to be assembled. The assembler rearranges the control section so that the
executable instructions are grouped together and the data areas are grouped
together. Symbols are not resolved in the order they appear in the source
program, but in location counter sequence.
SOURCE MODULE
LINKED MODULE
(shown in source code format)
┌──────────────────────────────────┐ ┌──────────────────────────────────┐ ─┐
│ INST CSECT │ │ │ controlled │
│ LR 12,15 ├──────────────────►│ LR 12,15 │ by INST │
│ USING INST,12 ├──────────────────►│ USING INST,12 │ location │
│ . │ │ . │ counter │
│ . │┌─────────────────►│ TM CODE,X'3' │ │
│ DATA LOCTR ││┌────────────────►│ BM NEWREC │ │
│ INPUTREC DS CL8 ├┼┼───────────┐ │ │ │
│ RECCODE DS CL1 ├┼┼─────────┐ │ │ │ │ control
│ . │││ │ │ │ │ ├── section
│ INST LOCTR │││ │ │ │ │ │ INST
│ TM CODE,X'3' ├┘│ │ │ ├ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ── ─ ┤ │
│ BM NEWREC ├─┘ │ └────►│ INPUTREC DS CL8 │ controlled │
│ . │ └──────►│ RECCODE DS CL1 │ by DATA │
│ DATA LOCTR │ │ . │ location │
│ VAL1 DC F'56' ├──────────────────►│ VAL1 DC F'56' │ counter │
│ VAL2 DC F'84' ├──────────────────►│ VAL2 DC F'84' │ │
│ . │ │ . │ │
│ . │ ├──────────────────────────────────┤ ─┘
│ NEXT CSECT │ │ │ control
│ │ │ │ section
│ │ │ │ NEXT
Figure 19. Use of Multiple Location Counters
| The interactions of the LOCTR instruction with sections, classes, and parts is
| described at “LOCTR Instruction” on page 191.
Addressing
This part of the chapter describes the techniques and introduces the instructions
that let you use symbolic addresses when referring to instructions and data. You
can address code and data that is defined within the same source module, or code
and data that is defined in another source module. Symbolic addresses are more
meaningful and easier to use than the corresponding object code addresses
required for machine instructions. The assembler can convert the symbolic
addresses you specify into their object code form.
Chapter 3. Program Structures and Addressing 63