Studying the design and implementation of a number of computer has led to some general hints for system design. They are described here and illustrated by many examples, ranging from hardware such as the Alto and the Dorado to application programs such as Bravo and Star. 1.

This paper presents an overview of the Cedar programming environment, focusing on its overall structure-that is, the major components of Cedar and the way they are organized. Cedar supports the development of programs written in a single programming language, also called Cedar. Its primary purpose is to increase the productivity of programmers whose activities include experimental pro-gramming and the development of prototype software systems for a high-performance personal computer. The paper emphasizes the extent to which the Cedar language, with run-time support, has influenced the organization, flexibility, usefulness, and stability of the Cedar environment. It high-lights the novel system features of Cedar, including automatic storage management of dynamically allocated typed values, a run-time type system that provides run-time access to Cedar data type definitions and allows interpretive manipulation of typed values, and a powerful deuice-independent imaging model that supports the user interface facilities. Using these discussions to set the context, the paper addresses the language and system features and the methodologies used to facilitate the integration of Cedar applications. A comparison of Cedar with other programming environments further identifies areas where Cedar excels and areas where work remains to be done.

Improving the performance of C programs has been a topic of great interest for many years. Both hardware technology and compiler optimization research has been applied in an effort to make C programs execute faster. In many application domains, the C++ language is replacing C as the programming language of choice. In this paper, we measure the empirical behavior of a group of significant C and C++ programs and attempt to identify and quantify behavioral differences between them. Our goal is to determine whether optimization technology that has been successful for C programs will also be successful in C++ programs. We furthermore identify behavioral characteristics of C++ programs that suggest optimizations that should be applied in those programs. Our results show that C++ programs exhibit behavior that is significantly different than C programs. These results should be of interest to compiler writers and architecture designers who are designing systems to execute object-oriented programs.

This paper describes experiments that apply machine learning to compress computer programs, formalizing and automating decisions about instruction encoding that have traditionally been made by humans in a more ad hoc manner. A program accepts a large training set of program material in a conventional compiler intermediate representation (IR) and automatically infers a decision tree that separates IR code into streams that compress much better than the undifferentiated whole. Driving a conventional arithmetic compressor with this model yields code 30 % smaller than the previous record for IR code compression, and 24 % smaller than an ambitious optimizing compiler feeding an ambitious general-purpose data compressor. Keywords Abstract machines, code compaction, code compression, compiler intermediate languages and representations, data compression, decision trees, machine learning, statistical models, virtual machines.

This dissertation presents the thesis that good and usable instruction sets can be automatically derived for a specified data path and benchmark set. This is achieved by a multistep process: generating execution traces for the benchmark programs, sampling these traces to form a large set of small code segments, optimally recompiling these segments using exhaustive search, and finding the cover of the new instructions generated that optimizes the performance metric. The complete process is illustrated by generating an instruction set for a processor optimized for executing compiled Prolog programs. The generated instruction set is compared with the hand-designed VLSI-BAM instruction set. The automatically designed instruction set is smaller and has only a few percent less performance on th...

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In an effort to relate static measurements of machine code instructions and addressing modes to their dynamic counterparts, both types of measurements were made on nine different machines using a large and varied suite of programs. Using classical regression analysis techniques, the relationship between static architecture measurements and dynamic architecture measurements was explored. The statistical analysis showed that many static and dynamic measurements are strongly correlated and that it is possible to use the more easily obtained static measurements to predict dynamic usage of instructions and addressing modes. With few exceptions, the predictions are accurate for most architectural features. Index Terms---Instruction sets, performance evaluation, computer architecture, dynamic measurements, static measurements, machine design. I. Introduction Static measurements of program code at machine level are generally thought to be useful for determining textual space needs while dynam...

This paper describes the application of a general data compression algorithm to assembly code. The system is retargetable and generalizes cross-jumping and procedural abstraction. It can be used as a space optimizer that trades time for space, it can turn assembly code into interpretive code, and it can help formalize and automate the traditionally ad hoe design of both real and abstract machines. 1.