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Assembler Language Programming: Basic
| Duration: 5 days |
| Participants: This courses is designed for the beginner assembler language application programmer who needs to code, maintain, and/or debug application programs written in zSeries, System/390, or System/370 Assembler Language. |
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Objectives:
Upon successful completion of this course you will be able to:
- Describe the steps used in the assembly process. - Entry and return macros and other standards for coding assembler programs. - Code in a recommended program organization that includes modular routines, standard register usage, DSECTs, ORGs that are self-adjusting for length changes, and well-documented maintainable code. - Define and use assembler pseudo-instructions. - Code all the macros for processing QSAM files (physical sequential files) using both Move mode and Locate mode. - Code the instructions for compare and branch looping. - Code data validation routines that check for valid input data, including numeric validation. - Code report programs that use editing to create formatted output fields. - Code assembler language programs that use: standard linkage conventions, data area and constant definitions, decimal arithmetic operations, data validation, data movement operations, and typical SS instructions, including TR, TRT, MVCL, CLCL, and SRP. - Use multiple base registers and literal control for managing large programs. - Code "above the line" assembler language programs that use 31-bit addressing and describe the instructions that are restricted to 24-bit addressing. - Debug assembler language programs using SNAP dumps and system-provided storage dumps and standard debugging techniques. - Use Principles of Operation and other IBM books available in Book Manager as well as those in QuickRef. |
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Overview:
- This course teaches how to use the zSeries, System/370, or System/390 Assembler Language instruction set. It includes standards for coding assembler programs, discussions of the base-displacement technique of addressing main storage, use of hexadecimal notation for identifying storage addresses and contents, coding rules and standards, the assembly process, standard QSAM I/O macros, "above and below the line" coding considerations, and basic dump reading. - Emphasis is placed on modular and structured programs and register use to facilitate debugging and dump reading. |
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Course Sequence:
- After taking this course, developers wishing to be more proficient in assembler should take our 'Intermediate Assembler Language Programming' course. |
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Prerequisites:
Before taking this course, you should be able to:
- Program in a procedural language, such as COBOL. - Understand basic data processing concepts and terminology. - Code basic JCL statements. - Understand programming fundamentals, such as data manipulation, looping, conditional processing, and I/O. |
| Format: Lecture and hands-on workshops. |
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Topic Outline:
- Basic Assembler Language Programming What is Assembler? Reference Books and Manuals - Prepare and Run Assembler Programs Sample Program Assembler Syntax Rules for Labels Program Preparation - Numbering Systems and Data Storage Main Storage and AMODE Concepts of Bases Binary Hexadecimal Converting Between Hexadecimal and Binary Converting Numbers What Does The Hex Mean? Data Representation Data Sizes Character Data Zoned Decimal Packed Decimal Pack a Number Packed Decimal Data Unpack a Packed Decimal Number Fixed Binary Point Numeric Edited Hexadecimal Arithmetic IBM Mainframe Data Forms Converting Between Number Systems Strongly vs Weakly Typed Data Define Storage, Define Constant DS and DC Location DC Continuation Truncation and Padding DC Storage Types DS / DC Structures and ORG - Displacement Concepts VSAM File Organization KSDS - Base Displacement Concepts General Purpose Registers GPR Typical Usage Base Displacement Concept Establish Base Register Labels Translate to Base Displacement Machine Instruction Formats Review: Machine Instruction Format RR Machine Instruction Format SS Machine Instruction Format - Program Logic: Arithmetic and Modularization Entry and Exit Linkage Arithmetic Sequence for Raw Data Arithmetic Sequence for Stored Data AP and SP Branch Instructions Structured Code Using Multiple Registers Structured Code Using Just One Register - Debugging Tips Simple Debugging Tips Debugging S0Cn Abends More Simple Debugging Tips Eye Catcher Literal SNAP Macro - Moving Data Moving Data Concepts Moving Data MVC Command MVI Command Tips for Handling Negatives Zone vs Numeric; MVZ and MVN - More Packed Instructions Self-Defining Constants and LTORG ORG to Extend a Record ORG to Redefine a Field ORG for VB Records Self-Defining Constants vs SI ZAP Multiply Packed Concept Divide Packed Concept Truncating Packed Numbers Decimal Places and MVN Decimal Places and MVO Rounding - SRPVSAM File Organization - Compare Values and Branch Compares Branch After Compare Branch After Arithmetic RX Instructions - Editing Numbers and Printing Records Types of Instructions Numeric Editing (ED) Common Editing Pattern Characteristics LA and BCTR EDMK Fancy Equates for Lengths Printing Reports Printing Checklist - Fixed-Point Binary Instructions FPB Logic for Processing Binary Instruction Set Introduction Benefits and Limitation FPB Typical Sequence FPB Multiply FPB Divide Load and Test Register Insert Character - Basic Table Processing BCT LOOPS with TABLES - Packed Decimal BCT LOOPS with TABLES – Fixed-Point Binary BCT Loop with LTR Advanced Looping Instructions - Program Sectioning and DSECTS Multiple Base Registers DSECT Get and Put Locate with DSECT Put Locate - TR, TRT, and LA Instructions Load Address (LA) Translate (TR) - To Convert Bytes to Different Bytes Translate (TR) - To Convert to Lowercase Translate and Test (TRT) - To Test Bytes Numeric Test Fancy Lengths Examples List of Extended Mnemonics Available |
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