Assembler Programming

Duration

6 to 8 hours

Overview

Audience

System or application programmers who code Assembler programs or maintain system related programs and user exits; this course reinforces good Assembler programming techniques and introduces more advanced techniques like re-entrant coding and executing in access register mode. The student is guided through the creation of two Assembler programs in the practice sessions.

Prerequisites

Completion of the courses Introduction to Assembler and Assembler Instructions, knowledge of programming concepts, and experience with OS/390 and System/390 architecture.

Objectives

After completing this course, the student will be able to identify:
• How to code more advanced Assembler programs, including re-entrant programs and programs that utilize access registers to address data spaces
• How to interpret Assembler listings of their assembled programs

Course Content

Program Organization

Program Organization
Register and Linkage Conventions
Passing Parameters to Assembler Programs

Linkage Conventions

Caller Provided Save Area
System Provided Linkage Stack
Prologue and Epilogue of an Assembler Program
370/ESA Environments

Address Modes

General Overview of Assembler Program Structures
Bi-Modal Addressing
Programming Re-Entrant Code
High Level Assembler Extensions

Data Spaces

Data Space Access Register Programming
Addressing Modes
Example of Moving Data into a Data Space

Assembler Program Listing

A Set of Programming Assignments
Solution to Exercise 1
Solution to Exercise 2
Hints on the Exercises and Assembler Programming