High Level Assembler: Classic.

This course covers the Assembler and the application-programmer oriented hardware instructions that have been available from the introduction of the S/360 and that were added over the first 20 years or so of the architecture. It is estimated that 90% of existing Assembler applications use only the instructions covered in this course.

The course is intended for:

• Experienced programmers needing to learn Assembler
• Assembler programmers needing to brush up on their Assembler skills

This overview comes in three parts, which are presented in sequence below:

1. Course Description
2. Course Objectives
3. Topical Outline

Course Description

Recommended Duration: 5 Days

Benefits: Students who complete this course will be able to write or maintain basic Assembler programs. The emphasis is on learning all the hardware instructions used by applications programmers as well as learning the basic interfaces to MVS, OS/390 or z/OS from Assembler language programs.

Audience: Experienced programmers needing to learn Assembler as an additional language or who need a refresher in Assembler. This course may also be used to teach Assembler as a first language, but it should probably be extended to seven days.

Prerequisites: At the very least the student entering this course should have background in using ISPF/PDF or a similar product used for creating programs and submitting jobs. Some experience in writing programs in a third generation language such as COBOL, PL/I, FORTRAN, or C.

Related IBM Materials.
This course is drawn from these IBM manuals; access to them in the classroom is required (via hardcopy, BookManager, etc.):

• SA22-7201 - Principles of Operation
• GX20-0406 - Reference Summary
• SC26-4940 - High Level Assembler reference

Major Topics Include:

• Hardware fundamentals (registers, memory, addressing)
• Machine instructions
• The Assembler
• Data formats (character, packed decimal, binary)
• Working with files and program linkages
• Calculations: rounding, editing, planning results (significant digits, implied decimal positions)
• Loops and tables
• Multiple base registers
• DSECTs, ORG, and EQU

Exercises: There are 14 hands-on exercises

Note 1:
This course covers the Assembler and the application-programmer oriented hardware instructions that have been available from the introduction of the S/360 and that were added over the first 20 years or so of the architecture. It is estimated that 90% of existing Assembler applications use only the instructions covered in this course.

Note 2:
We do not cover any instructions in the following categories: floating point, vector, privileged, semi-privileged.

Note 3:
The course integrates the latest features of the High Level Assembler (HLASM).

Note 4:
The follow on courses are:

1. High Level Assembler: Interfaces
2. High Level Assembler: Update
3. High Level Assembler: Update for z/Architecture

Note 5:
All course material is in American English. Oral explanation will be in English by default, but is also available in Dutch, German, and/or French.

This course description Copyright © 2001 by Steven H. Comstock. All rights reserved.

Course Objectives

On successful completion of this course, the student, with the aid of the appropriate reference materials, should be able to:

1. Code a program in Assembler language that uses the following techniques:
   
   
   1. Use standard save area linkage techniques
      
      
   2. Define and process sequential files with fixed length records, including:
      
      
      • Reading and writing records from / to DASD files
      • Reading and writing records from / to tape files
      • Writing records to print files, including formatting detail lines, but not using carriage control characters or other report management techniques
        
      
      
   3. Perform calculations using packed decimal arithmetic, including formatting results with edit patterns and half-adjusting results
      
      
   4. Perform calculations using binary integer arithmetic
      
      
   5. Work with data in tables, including defining and accessing the elements in a table
      
      
   6. Use DSECTs to describe structures
      
      
   7. Use multiple base registers
   
   
2. Document the program listing with comments to assist in maintenance and understanding of the code
   
   
3. Debug the resulting code of program-check type errors

Note:
This course supports the MVS, OS/390, and z/OS environments.

These course objectives Copyright © 2001 by Steven H. Comstock. All rights reserved.

Topical Outline

Day One

Fundamentals

• Programming concepts
• Source, Object, and Load Modules
• Memory and Data Representation
• Addressing
• The CPU
• Computer Exercise: Setting Up For Programming

• Machine Instruction Formats
• Base / Displacement Addresses
• Assembler Language and the High Level Assembler (HLASM)
• Basic Program Structure Requirements
• Computer Exercise: Coding, Assembling, Linking, Running

Data Description, Moving Data, Record Processing

• Defining Constants and Work Areas (DS and DC Statements for Character Type Data)
• MVC instruction
• Instruction Styles and Formats
• Introduction to Branching
• Introduction to Record Processing
• Data Organization
• DCB Macros
• OPEN, GET, PUT, CLOSE Macros
• Record Processing - An Example
• Computer Exercise: File To File Program

Compares, Branches, and Linkages

• Record Layouts
• Programming Techniques: MVC
• CLC Instruction and the Condition Code
• BC, BCR Instructions
• Extended mnemonics
• BAS, BASR, BAL, BALR, IPM Instructions

Day Two

More Fundamentals

• More on Addressability
• What Can Go Wrong?
• Storage Protect Keys
• Computer Exercise: List Fields From A Record

Packed Decimal Arithmetic

• Zoned Decimal Format
• Packed Decimal Format
• DC and DS for Zoned and Packed Type Data
• Packed Decimal Instruction Set: PACK, UNPK, AP, SP, MP, DP, CP, ZAP
• Arithmetic Concerns
  • Significant digits
  • Keeping Track of Decimal Points
• Computer Exercise: Packed Decimal Calculations

More Assembler and Arithmetic Concepts

• Redefining Storage
• Creating Data Structures
• The Assembly Listing Components
• Introduction to Debugging
• Rounding
• MVO - Move With Offset
• SRP - Shift and Round Packed
• Computer Exercise: Half-Adjusting Data

Day Three

Editing Packed Decimal Fields

• DS / DC for Hexadecimal Data
• ED Instruction
• Edit Patterns
• Computer Exercise: Edit Packed Decimal Data

A Deeper Look at Instruction Formats

• DC / DS for Binary Data Type
• Addresses in Instructions
• Explicit Coding - Review
• Tables
• LA Instruction
• Instruction Formats (SS, RR, RX)
• MVI, CLI Instructions
• Instruction Formats (SI)
• MVN, MVZ Instructions
• Computer Exercise: Using Immediate Instructions

Binary Integer Data

• Binary Integer Data Formats
• Twos Complement
• DC/DS for Fullword, Halfword, and Doubleword Binary Data
• Boundary Alignment
• CVB, CVD Instructions
• L, LR, ST Instructions
• A, AR, S, SR, C, CR, MR, M, DR, D Instructions
• Concerns Of Working With Binary Integers
• Working With Binary Numbers - An Example
• Computer Exercise: Binary Arithmetic Computations

Day Four

More Binary Instructions

• Compare Instructions
• LPR, LNR, LCR Instructions
• Logical Arithmetic: AL, ALR, CL, CLR, SL, SLR
• Halfword Instructions: AH, CH, LH, MH, SH, STH

EDit and MarK

• EDMK and floating currency signs
• Computer Exercise: Floating Dollar Sign

Loops and Tables

• Literals
• LTORG
• Address Constants
• EQU - Equate Symbol
• Loop Control
• Tables
• BCT, BCTR, BXLE, BXH, IC, STC
• Computer Exercise: Table Processing

Day Five

Multiple base registers, DSECTS, ORG

• STM, LM
• Multiple Base Registers
• CNOP
• Dummy sections - DSECTs
• ORG
• Computer Exercise: Using DSECTs

Working With Bits

• O, OC, OR, OI, N, NC, NR, NI, X, XC, XR, XI
• Sorting Tables
• LTR, TM Instructions
• More on EQU
• Computer Exercise: Sorting a Table

Shift Instructions

• SRL, SRA, SLL, SLA, SRDL, SRDA, SLDL, SLDA Instructions
• Code Fragment: Display Bit String

Translate

• Instruction Set: TR
• Code Fragment: Display Hex String
• Code Fragment: Direct Access to a Table
• Computer Exercise: Build a Table Dynamically

TRanslate-and-Test and EXecute

• TRT - Translate and Test
• EX - Execute
• TRT and EX

Strings

• String Handling
• ICM, CLM, STCM Instructions
• MVCL, CLCL Instructions
• MVCIN Instruction

Setting Addressing Mode

• Addressing Mode
• AMODE and RMODE
• BASSM - Branch And Save And Set Mode
• BSM - Branch and Set Mode

This topical outline Copyright © 2001 by Steven H. Comstock. All rights reserved.

Remarks? Questions? More information? Select the topic of your choice or e-mail us with your questions.

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