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Z80 programming for logic design
Assemblers and loaders (3rd Edition) D W Barron, Macdona/d and lanes' Computer Monographs (19 78) £3.95 102pp The current explosion in the use of microprocessors has created a fresh interest in assembly language programming. Professor Barron, while expressing the hope that high level languages will ultimately previal, has recognized this current interest and extensively revised his elegantly written text on assemblers and loaders to produce this third edition. The text consists of a concise, readable 'state of the art' report on the design, implementation, and operation of assemblers and their associated loaders. As such it will serve as an excellent source of ideas for students or practitioners of the art of writing assemblers and loaders. It may also be read by experienced assembly language programmers who wish to further their knowledge in this field, possibly for the purpose of critically evaluating various available assemblers. The bias of earlier editions towards mainframes has been changed, and
minis and micros now receive considerable attention, particularly the PDP11, and to a lesser extent the 8080. The text describes features found in most basic assemblers/loaders, •~nd contains chapters on more elaborate developments such as macroassemblers and high level assemblers. The chapter on metaassemblers (i.e. assemblers which may be user programmed to handle assembly language for any processor) seems particularly relevant at this time. Professor Barton indicates that the lack of interest in this field ranks as one of the greatest might-have-beens in the history of computer science. Hopefully this may prove to be a prejudgement, and his book may spur the development of a portable metaassemblet which would greatly reduce the system software investment required when changing microprocessor types. For such a specialised market the cost of £3.95 for 102 pages is not unreasonable, although the quality of paper used leaves much to be desired.
Dr Henry Davie University o f Glasgow
Engineers or programmers who are considering using the ZS0 for either logic replacement or as a design aid for logic simulation, should find this publication very useful. It is an easy book to read, with a type style enabling one to scan through chapters quickly using the bold type, and dwelling on areas of interest using the light type. The book's 360 pages are packed with information, though unfortunately, over one third of it is taken up in listing and explaining the vast number of Z80 program instructions - information which is normally available free of charge to any Z80 user from the component suppliers. Despite this, the book is a very worthwhile publication.
Les Price Trivector Systems
Analog systems for minicomputers and microprocessors Patrick H Garrett, Reston (Prentice Hall in UK) £14.55, 248pp
Z80 programming for logic design Adam Osborne, Jerry Kane, Russell Rector, Susant~aJacobson, Osborne and Associates, California, USA (1978) S7.50 360pp This soft backed book covers a very specific application of one particular microprocessor,- the Zilog/Mostek ZS0. The ZS0 is used here to replace an area of discrete logic, namely the Qume impact printer peripheral interface. It does this by software simulation of the replaced logic, and direct drive of the printer electrics via a ZS0 parallel input/output interface chip supported by suitable buffer components. Individual logic component simulation programs are built up to
120
finally produce a full software copy of the hardware interface. An alternative program is then produced by taking a 'black box' functional approach to the problem. These two programs then being compared and discussed in a style such that both programmers and engineers would be able to understand and use it. The case for using the Z80 in this particular application is not discussed, nor are the possibly more suitable alternatives such as FPLA's (fixed program logic arrays) or dedicated microprocessor chips with integral PROM, RAM, and I/O. An analysis of the comparative design costs, production costs, and support costs would have been very interesting.
This book gives a clear and concise account of current practices employed in analogue signal acquisition, conditioning and conversion, with adequate references for in-depth reading on these key topics. The book has an easily understood presentation on the error analysis of the important instrumentation amplifier, together with a comparative review on analogue to digital conversion techniques. These sections enable potential users to understand manufacturer's specifications and assess the relevance of a device to a specific application. However the chapters describing other topics such as transducers and process controllers only give a cursory review and do not add much to the value of the book. Given the intended scope stated by the author it is inevitable that some areas be treated very briefly.
microprocessors and microsystems
minis and micros now receive considerable attention, particularly the PDP11, and to a lesser extent the 8080. The text describes features found in most basic assemblers/loaders, •~nd contains chapters on more elaborate developments such as macroassemblers and high level assemblers. The chapter on metaassemblers (i.e. assemblers which may be user programmed to handle assembly language for any processor) seems particularly relevant at this time. Professor Barton indicates that the lack of interest in this field ranks as one of the greatest might-have-beens in the history of computer science. Hopefully this may prove to be a prejudgement, and his book may spur the development of a portable metaassemblet which would greatly reduce the system software investment required when changing microprocessor types. For such a specialised market the cost of £3.95 for 102 pages is not unreasonable, although the quality of paper used leaves much to be desired.
Dr Henry Davie University o f Glasgow
Engineers or programmers who are considering using the ZS0 for either logic replacement or as a design aid for logic simulation, should find this publication very useful. It is an easy book to read, with a type style enabling one to scan through chapters quickly using the bold type, and dwelling on areas of interest using the light type. The book's 360 pages are packed with information, though unfortunately, over one third of it is taken up in listing and explaining the vast number of Z80 program instructions - information which is normally available free of charge to any Z80 user from the component suppliers. Despite this, the book is a very worthwhile publication.
Les Price Trivector Systems
Analog systems for minicomputers and microprocessors Patrick H Garrett, Reston (Prentice Hall in UK) £14.55, 248pp
Z80 programming for logic design Adam Osborne, Jerry Kane, Russell Rector, Susant~aJacobson, Osborne and Associates, California, USA (1978) S7.50 360pp This soft backed book covers a very specific application of one particular microprocessor,- the Zilog/Mostek ZS0. The ZS0 is used here to replace an area of discrete logic, namely the Qume impact printer peripheral interface. It does this by software simulation of the replaced logic, and direct drive of the printer electrics via a ZS0 parallel input/output interface chip supported by suitable buffer components. Individual logic component simulation programs are built up to
120
finally produce a full software copy of the hardware interface. An alternative program is then produced by taking a 'black box' functional approach to the problem. These two programs then being compared and discussed in a style such that both programmers and engineers would be able to understand and use it. The case for using the Z80 in this particular application is not discussed, nor are the possibly more suitable alternatives such as FPLA's (fixed program logic arrays) or dedicated microprocessor chips with integral PROM, RAM, and I/O. An analysis of the comparative design costs, production costs, and support costs would have been very interesting.
This book gives a clear and concise account of current practices employed in analogue signal acquisition, conditioning and conversion, with adequate references for in-depth reading on these key topics. The book has an easily understood presentation on the error analysis of the important instrumentation amplifier, together with a comparative review on analogue to digital conversion techniques. These sections enable potential users to understand manufacturer's specifications and assess the relevance of a device to a specific application. However the chapters describing other topics such as transducers and process controllers only give a cursory review and do not add much to the value of the book. Given the intended scope stated by the author it is inevitable that some areas be treated very briefly.
microprocessors and microsystems