IBM GF20-0385-0 An Introduction to Microprogramming Dec71 free download

File name GF20-0385-0_An_Introduction_to_Microprogramming_Dec71.pdf

GF20-0385-0 Data Processing An Introduction to Techniques Microprogramming This document describes some aspects of microprogram- ming as it has been and is being used in certain IBM processirig units. It is intended to provide a general understanding of the subject. To achieve this objective, the document has been divided into two parts-Part I provides the reader with elementary concepts: what microprogramming is, what it does, how it is used, etc. This material is sufficient for the reader who wishes only a broad understanding of microprogramming. Part I requires ~o prerequisite knowledge by the reader other than basic data processing concepts. Part II is far more detailed and is intended to provide an understanding of some microprogramming specifics. While the System/370 Models 135 and 145 are used as instructional devices, the material is not intended to be a description of how, or through what vehicles, these devices are microprogrammed. Part II requires close attention to detail, and is for those who wish a more explicit description than that provided by Part I. Part II presumes some knowledge of assembler language program- ming concepts as well as a basic familiarity with the principles of complement arithmetic. The document concludes with some recommendations for further reading. IBM does not provide educational or instructional manuals for any specific microprogrammable device. However, the field engineering maintenance documents peculiar to the device in question, as an adjunct to their primary objective, may contain further details on certain microprogram mabie aspects of that device. CONTENTS Part I OverView . . . . . . . . . . . . . . . . . . . . 1 Simulation of Functions . . . . ... . . . . . . .. 1 Microcode: The IBM System/360 . . . . . . . . . . . . .. 1 Read Only Storage . . ... . . . . ... 2 Writable Control Storage 2 System/370 . . . . . . . . . . ... 3 Special Features . . . . . . . . . . . . . 4 Consideratio