TAS(ID:3250/tas001)Telefunken-Assembler-SpracheTelefunken-Assembler-Sprache References: A programming language, "PS440", is described which provides many of the advantages of higher level languages while at the same time maintaining some needed facilities of assembly language. We begin with some introductory remarks about the aim of the PS440-project and the approach in the implementation and then give - a description of the data types, - their use in expressions, - control statements in PS440 - and the runtime services available for object programs. Extract: PS440 The language PS440 was developed by G. Goos, K. Lagally and the author as members of a working group in the computing center of the Technical University of Munich, beginning in July 1969. The working group was mainly concerned with the development and construc- tion of a timesharing system for a German-made computer (AEG-TELEFUNKEN type TR440) with two processors and three satellite computers (AEG-TELEFUNKEN type TR86). The TR440 is a large computer and the operating system for it is accordingly a b~g project which justifies the effort of developing an implementation language for it. +~ All operating systems for TELEFUNKEN computers have up to now been written in assembler languages. The development of this higher level language for developing an operating system was for the following reasons: - The majority of the programmers for this operating system have already had experience with higher level languages but have almost never programmed larger projects in assembler code. Writing in assembler would be inconvenient for these programmers. - Simple, straightforward sequences of operations, such as those in arithmetic expressions and in address calculations need complicated formulations in assembler. - Programs in assembler language are not self explanatory, and are hard to follow unless they are supplemented with comments, description of intent, and flow charts. - Assembly programs therefore often contain many trivial coding errors, which are hard to detect since efficient and easily applied debugging aids hardly exist, and tempo- rary changes needed during test phases are difficult to implement. One might ask why another programming language had to be developed because higher level programming languages (FORTRAN, ALGOL, or PL/I) have already been used for the pro- gramming of basic software. But they have disadvantages too. Since their concept is machine independent, they do not allow full use of all built in features of the computer. Performance of the programs cannot be influenced and optimized locally. The fixed data types with implicit conversions (floating point/fixed point) do not always allow a value to be interpreted in a number of ways as being of different type depending on the operational context. Extract: TAS In addition we allowed the direct insertion of TAS (TELEFUNKEN assembler language) statements in the PS440 source, therefore demanding the existence of a TAS assembler as part of the PS440 compiler. We take care of this by translation the whole program into TAS and using the TAS assembler as the second pass of the PS440 compiler implementation. Allowing assembly language fragments in PS440 avoids the difficulty of assuring comple- teness in the provided functions. In our case the language was already useful before all properties of PS440 were implemented. Furthermore this decision reduced the cost of implementation since the generated TAS program can make full use of all assembler prop- erties. In addition, assembler language programs already developed for other purposes, such as for earlier operating systems, can be inserted and used without any difficulty. On the other hand we must realize that we open the door to all sorts of undesirable pro- gramming styles, language restrictions and compiler problems. For example we have to use the same type of global and local range of variables as implemented in the assembly lan- guage. Otherwise we would have to give up the possibility of using variables defined in PS440 in the TAS insertions. A PS440 program therefore consists of one or more segments, leaving the simple alternative that names can either be global for the whole program or local in a segment. in [ACM] SIGPLAN Notices 6(10) October 1971 Proceedings of the SIGPLAN symposium on Languages for system implementation 1971, Lafayette, Indiana, United States; October, 1971 view details [321 programming languages with indication of the computer manufacturers, on whose machinery the appropriate languages are used to know. Register of the 74 computer companies; Sequence of the programming languages after the number of manufacturing firms, on whose plants the language is implemented; Sequence of the manufacturing firms after the number of used programming languages.] in [ACM] SIGPLAN Notices 6(10) October 1971 Proceedings of the SIGPLAN symposium on Languages for system implementation 1971, Lafayette, Indiana, United States; October, 1971 view details The exact number of all the programming languages still in use, and those which are no longer used, is unknown. Zemanek calls the abundance of programming languages and their many dialects a "language Babel". When a new programming language is developed, only its name is known at first and it takes a while before publications about it appear. For some languages, the only relevant literature stays inside the individual companies; some are reported on in papers and magazines; and only a few, such as ALGOL, BASIC, COBOL, FORTRAN, and PL/1, become known to a wider public through various text- and handbooks. The situation surrounding the application of these languages in many computer centers is a similar one. There are differing opinions on the concept "programming languages". What is called a programming language by some may be termed a program, a processor, or a generator by others. Since there are no sharp borderlines in the field of programming languages, works were considered here which deal with machine languages, assemblers, autocoders, syntax and compilers, processors and generators, as well as with general higher programming languages. The bibliography contains some 2,700 titles of books, magazines and essays for around 300 programming languages. However, as shown by the "Overview of Existing Programming Languages", there are more than 300 such languages. The "Overview" lists a total of 676 programming languages, but this is certainly incomplete. One author ' has already announced the "next 700 programming languages"; it is to be hoped the many users may be spared such a great variety for reasons of compatibility. The graphic representations (illustrations 1 & 2) show the development and proportion of the most widely-used programming languages, as measured by the number of publications listed here and by the number of computer manufacturers and software firms who have implemented the language in question. The illustrations show FORTRAN to be in the lead at the present time. PL/1 is advancing rapidly, although PL/1 compilers are not yet seen very often outside of IBM. Some experts believe PL/1 will replace even the widely-used languages such as FORTRAN, COBOL, and ALGOL.4) If this does occur, it will surely take some time - as shown by the chronological diagram (illustration 2) . It would be desirable from the user's point of view to reduce this language confusion down to the most advantageous languages. Those languages still maintained should incorporate the special facets and advantages of the otherwise superfluous languages. Obviously such demands are not in the interests of computer production firms, especially when one considers that a FORTRAN program can be executed on nearly all third-generation computers. The titles in this bibliography are organized alphabetically according to programming language, and within a language chronologically and again alphabetically within a given year. Preceding the first programming language in the alphabet, literature is listed on several languages, as are general papers on programming languages and on the theory of formal languages (AAA). As far as possible, the most of titles are based on autopsy. However, the bibliographical description of sone titles will not satisfy bibliography-documentation demands, since they are based on inaccurate information in various sources. Translation titles whose original titles could not be found through bibliographical research were not included. ' In view of the fact that nany libraries do not have the quoted papers, all magazine essays should have been listed with the volume, the year, issue number and the complete number of pages (e.g. pp. 721-783), so that interlibrary loans could take place with fast reader service. Unfortunately, these data were not always found. It is hoped that this bibliography will help the electronic data processing expert, and those who wish to select the appropriate programming language from the many available, to find a way through the language Babel. We wish to offer special thanks to Mr. Klaus G. Saur and the staff of Verlag Dokumentation for their publishing work. Graz / Austria, May, 1973 in [ACM] SIGPLAN Notices 6(10) October 1971 Proceedings of the SIGPLAN symposium on Languages for system implementation 1971, Lafayette, Indiana, United States; October, 1971 view details |