Assembly Language Programming Research Articles

Structured programming in assembly language

Structured design and programming techniques can be extended from high-level languages to assembly language. Over the past three years at Brown University, beginning assembly language programmers have been successfully taught these techniques using clearly defined standards. These standards and the solutions to several of the typical problems that arise in structured assembly language programming are discussed in this paper.

The use of data flow diagrams in an introductory course in assembly language programming and machine architecture

The use of data flow diagrams in an introductory course in assembly language programming and machine architecture

Implementation of experimental designs and storage of results in the PACER system of on-line control

PACER has been developed for use with assembly language programs running on a DEC PDP-11/05 machine. The system comprises an Executive and associated routines to perform many of the tasks common to experiment control programs. Attention has been given to the provision of routines to allow the implementation of experimental designs. Experimental variables are referred to asfactors, and the values of these variables are manipulated indirectly through the use of numerical labels, orlevels. Factors are described in tabular form, and means are provided for the independent or joint randomization of the associated levels. Experimental results can then be stored as functions of specified factors and output at the end of a session in a format corresponding to the structure of the experimental design.

A real-time software system on the PDP-11 for two-channel EEG spectral analysis during surgery

Three functions are performed in real time by a stand-alone PDP-11 assembly language program. First two channels of EEG data are acquired by quantization techniques; second spectral analysis of the EEG data is carried out; third the resulting spectra are displayed as time compressed spectral profiles on an X − Y plotter. The method provides EEG time trends during anesthesia, permitting evaluation of brain functions.

An automated laboratory control system: Collection and analysis of behavioral and electro-physiological data

A system of man-machine interactive PDP-11 assembly language programs is described which presents stimuli to a subject and records and analyzes behavioral and evoked potential data. The system was designed for researchers with no knowledge of computer programming and enables the user to create complicated sequences of stimulus presentations (“trials”) and sequences of successive trials (“runs”), with no new programming required. The system is written for DEC.s DECLAB 11/40 system.

The Specification of Assemblers

The problem of applying formal techniques of program specification and verification to large complex programs is considered. It is argued that a practical solution requires a variety of techniques, including both procedural and nonprocedural specifications, hierarchical program organization, and the use of program transformations. In particular, a case is made for flexible problem-oriented choice of specification techniques and languages. These ideas are expanded by specifying a load-and-go assembler in three parts: a transduction grammar describing the correspondence between concrete and abstract syntax for assembly language programs; a set of transformations of the abstract form; and a nonconstructive axiomatic specification of the result of core assembly and loading of transformed abstract programs.

The COLUMBUS approach

This paper describes an interactive system-COLUMBUS-for the development of well-structured programs in assembly language, Cobol, and PL/I. One of the basic concepts employed is the use of Nassi/Shneiderman charts as the unique reference document. For specifying the control structures of a program, the programmer uses a set of control primitives which are common for all languages used. Data declarations and executable statements are taken from the individual language. This mixture is called the COLUMBUS source form. From this source form Nassi/Shneiderman diagrams and cross-reference matrices can be produced in a language-independent fashion; pure source for the individual languages is produced by a set of preprocessors in a language-dependent fashion. This paper illustrates the mechanisms involved by giving some small examples for the individual languages, and it also gives a brief history of the project and reports on quantitative and qualitative results obtained so far. The plans for future extensions are also explained.

A Propsed Method for Simpliofied Microcomputer Programming*

A key obstacle to wider application of the new microprocessors is the need to program in assembly language with fairly cumbersome instruction sets. We propose a new technique which will make it easy for applications-oriented non-programmers to generate efficient microcomputer programs without any need to learn assembly language. The user merely specifies an analog-computer-like block diagram whose intuitively meaningful block-operators specify standard mathematical operations (addition, multiplication, integration, etc.) and input/output operations (e.g., analog/digital conversion, switching, sensing). These standard operations are implemented as subroutines in the microcomputer read-only memory (ROM). An interactive editor/translator program running on a small minicomputer translates block-diagram specifications into a simple address table and loads it into the microcomputer memory (RAM, PROM, or ROM). This address table represents the block-diagram operation sequence and specifies successive jumps to the correct standard subroutines in ROM and data fetching/storing operations in the random-access memory.

An adaptable disk-oriented automatic diffractometer control program

A diffractometer control program is described which can be used without modification on all Picker Nuclear FACS-I diffractometer equipped with a DF-32 disk. The assembly language program provides a wide variety of preprogrammed data-collection options including an automatic crystal orientation checking algorithm which is described. The program is organized in semi-independent segments to facilitate modification and extension. Several laboratories currently use the program and documentation is available.

Notes from journals

Incorporating user-oriented features usually found only in much larger computers, the first models of the Eclipse line, the $100 and $200, use a high speed micro-programmed central processor, and can run with either; core or semiconductor memories, or both. The core and semiconductor memories are available with an error detection and correction feature that can find and correct; single bit errors caused by the computer. The semiconductor memories use a high-speed cache to increase memory speed. The Eclipse $100, the smaller of the two computers, will be used by oems or by end users who need a smaller system to meet their requirements. The Eclipse $100 is 5-1/4 inches high, and holds six standard Data General printed circuit boards. It costs $9200, with 16k bytes of core memory, and $10,700 with 16k bytes of semiconductor memory. Eclipse $100 deliveries will begin in December. The Eclipse $200, a system-oriented computer that can hold 16 printed circuit boards, will be used by system builders or end users who will build large scale computing systems around it. The Eclipse $200 is 10-1/2 inches high, and costs $16,300 with 32k bytes of core memory, and $19,300 with 32k bytes of semiconductor memory. Deliveries of the Eclipse $200 will begin in February. The instruction set of both Eclipse computers is microprogrammed in the central processor. There are over 40 new instruction in the Eclipse computers. Programs written on Nova computers will run on either the Eclipse $100 or $200. The central processor includes a Writeable Control Store making up to 256, 56-bit words available to write specialized micro-programmed instructions. The instruction set is enhanced to help programmers writing in assembly language or high-level language programs. Hardware memory stacks, supported by comprehensive instructions, make programming more efficient, while block, word, byte and bit manipulation instructions improve system performance. Instructions are both single word and double word instructions.

List and execute forms of macros

Macros are the means which the assembly language programmer may use to reduce his work. They place at his fingertips a great deal of power for a small amount of coding. System macros provided by the manufacturer give the assembly language programmer a similar amount of power or even more without requiring any coding at all from him. System macros are complicated to use; some require many parameters to be specified each time they are used. The programmer must take great care as he uses system macros because of the large numbers of parameters. The list and execute form provided for some system macros permit him to separate his parameter list from the actual request to perform the services. Since the mechanism and the effectiveness of this feature is not immediately apparent, this paper describes several uses to which the list and execute form may be put.

A machine independent course in processor organization and assembler language programming

Over the past three years the University of Scranton has been developing a computer science program. Since we could not hope to obtain the type of equipment, fast processors and compilers which many of the larger schools have, we developed several “canned programs” which could accept and act upon student input and give the student some degree of experience with computers which are not within our financial means. The heart of this development was a simulator we refer to as the SLIC ( S cranton's L ittle I nstructional C omputer) processor. We feel this simulator has a different purpose for its existence than some of the others which have been developed. The original purpose and the one on which we are concentrating in this paper was to give students some practical programming experience on “computers” which have different addressing schemes. We feel SLIC met this original purpose with great success. Its most important contribution to date is in the development of our course in Processor Organization and Assembler Programming. In making this course SLIC dependent, we believe we made it machine independent and as a result we feel we give our students a “feel” for computing which transcends the machine we have on campus.

The programming language PS440 as a tool for implementing a time-sharing system

The use of assembly language for the programming of basic software of a large operating system often proves inflexible and impractical. Writing the programs in assembly language is time-consuming and expensive. Furthermore, the programs are hard to read and difficult to modify. Nevertheless, assembly languages have facilities which must be preserved when higher level programming languages are to be used for basic software. 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.

IBM 360 Assembler language programming, Gopal K. Kapur, Wiley, New York, 1971. No. of pages: 560. Price: £4.50

IBM 360 Assembler language programming, Gopal K. Kapur, Wiley, New York, 1971. No. of pages: 560. Price: £4.50

A complete package for introducing computer science

Faced with the challenge of teaching large numbers of students without sacrificing quality, we have developed a complete "package" for teaching introductory computer science. This package consists of textbooks, notes, problem sets, labtutorial arrangements, instructional software, and visual aids for lectures, all developed at the University of Waterloo.The textbooks are "FORTRAN IV WITH WATFOR AND WATFIV" and "AN INTRODUCTION TO THE SPECTRE COMPUTER". The first text provides a thorough introduction to FORTRAN programming, whereas the second describes a hypothetical computer used for teaching purposes to introduce concepts in assembly language programming and machine organization. Notes supplement the texts by covering elementary ideas from boolean algebra, switching and automata theory, and hardware design. Consequently, we endeavour in this course to introduce students to various aspects of computer science, not just programming.Nevertheless, programming is a major part of computer science, and we feel that considerable hands-on experience is essential to a student's education. We provide unlimited access to the computer for all students with a turnaround time between one and two minutes for small jobs. This service is made possible by our fast FORTRAN compiler, WATFOR, which permits the computing centre to process between 3000 and 7000 undergraduate jobs daily on an IBM S/360 model 75. In addition, we simulate the SPECTRE machine via an interpreter, also with unlimited access to students.For lectures, we have prepared substantial lecture material in a set of 35 mm slides. We feel that this mode of presentation has numerous advantages for a large multi-section course, some of which are better visibility for students, easy review possibilities, lecturer cues, uniformity throughout the various sections, and improvement of presentation by new and inexperienced lecturers.This course is offered to approximately 1300 students yearly at Waterloo. Each student has two hours of lectures per week, as well as biweekly tests and problem sessions in alternate weeks. In order to assist us in the development of our package, we try to obtain as much student feedback as possible through the distribution of an extensive questionnaire to all students taking the course.

On-line program debugging

This paper describes a system which allows programmers to construct and debug assembly language programs in an on-line conversational manner, using a graphic display with light pen and keyboard. The amount of programs necessary to realize these functions is about 8000 machine instructions. The expected gain with this system is that it can reduce by a factor of between two and four the time required to prepare, write and debug new programs.

Design of an integrated programming and operating system, Part IV: The system's FORTRAN compiler

This paper is devoted to the 7090/94 version of the system's FORTRAN compiler, IBFTC, which translates FORTRAN IV language programs into MAP assembly language programs.