HLASM Language Reference

Addressing
| Summary of Source and Object Program Structures
| The differences between the load module model and the program object model,
| and their interactions with assembler language instructions, are summarized in the
| following table:
| Property
“Load Module” Model
“Program Object” Model
| Form of object program
One-dimensional module
Two-dimensional module
| Smallest indivisible independently Control section
Element and part
| relocatable component
| Residence Mode
Only one
One per class
| Addressing Mode
Only one
One per entry point
| Compatibility
Can be converted to program Can be converted to load module
| object
with limitations
| Assembler Option
NOGOFF or GOFF
GOFF only
| Assembler statements
CSECT, RSECT, START
CSECT, RSECT, START, CATTR,
| XATTR
| Assignable loadable-program
RMODE
RMODE, alignment, load type
| attributes
| External symbol types
SD/CM, LD, ER/WX, PR
SD, ED, LD, ER/WX, PR, PD
| External symbol maximum length 8 characters
256 characters
| External symbol scope
Module (WX), Library (ER)
Section, Module, Library,
| Import/Export
| External symbol attributes
AMode, RMode
AMode, RMode, scope, PSect name,
| linkage type, reference type,
| extended attributes
| Object module record types
ESD, TXT, RLD, END, SYM
HDR, ESD, TXT, RLD, END, LEN
| Address constant types
A, V, Q, CXD
A, V, Q, J, R, CXD
| Binding attributes
Catenate (SD),
Catenate (non-Merge classes),
| Merge-like (CM,PR)
Merge classes (Parts,
| Pseudo-Registers)
| Text types
Byte stream
Byte stream, records (structured and
| unstructured)
| Maximum contiguous text length 16MB
1GB
| Figure 21. Object Program Structure Comparison
Chapter 3. Program Structures and Addressing 73