摘要:

AbstractThe programming walkthrough is a method for assessing how easy or hard it will be for users to write programs in a programming language. It is intended to enable language designers to identify problems early in design and to help them choose among alternative designs. We describe the method and present experience in applying it in four language design projects. Results indicate that the method is a useful supplement to existing design approaches.

ISSN:0038-0644    

DOI:10.1002/spe.4380240102

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractRemote‐procedure calls (RPCs) allow distributed, high‐level language programs to communicate and synchronize in the usual manner via subprogram calls. One of the great challenges in RPC research is to preserve the traditiional call semantics despite the distribution and heterogeneity of the new environment.The main contribution of SUPRA‐RPC is in addressing the passing of subprograms as RPC parameters. In doing so, SUPRA overcomes a number of technical difficulties, stemming from scoping, side‐effects and other sources. Since supporting subprogram RPC parameters is harder than supporting non‐subprogram RPC parameters, the three (of six) components of the SUPRA architecture extend in novel ways the traditional functionality found in their counterparts in other RPC systems. The SUPRA stub generator extracts information not only from remote entry interfaces, but from any scope potentially referenced by a subprogram passed as an RPC parameter. In addition to the usual call‐ and accept‐stubs and the marshaling and unmarshaling routines, the generator constructs out‐of‐scope access stubs, callback' and callback‐handling‐stubs, and modified parameter subprograms and others. The SUPRA run‐time support manages a run‐time symbol table to keep track of referencing environments and out‐of‐scope objects. When an out‐of‐scope object is unavailable for access or execution on the server, the object is reached by a synchronous, ‘under‐the‐covers’ callback. The SUPRA process management supports servers with independent threads of control, manages (possibly nested) callbacks and pools of callback handler threads, and maintains correct identification of thread‐initiated calls or callbacks.A SUPRA prototype has been implemented on Sun Unix workstations. The prototype supports C, C++ and CommonLisp programs. A prototype graphical demonstration has been implemented as well, that represents RPC concepts in

ISSN:0038-0644    

DOI:10.1002/spe.4380240103

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractMost conventional compilers fail to allocate array elements to registers because standard data‐flow analysis treats arrays like scalars, making it impossible to analyze the definitions and uses of individual array elements. This deficiency is particularly troublesome for floating‐point registers, which are most often used as temporary repositories for subscripted variables.This paper presents a source‐to‐source transformation, calledscalar replacement, that finds opportunities for reuse of subscripted variables and replaces the references involved by references to temporary scalar variables. The scalar replaced variables are more likely to be assigned to registers by the coloring‐based register allocators found in most compilers than are their unreplaced counterparts. The algorithm presented here extends previous techniques for scalar replacement by allowing the presence of forward conditional control flow within loop bodies through the mapping of partial redundancy elimination to scalar replacement. Finally, experimental results show that scalar replacement is extremely effective. On kernels, integer‐factor improvements over code generated by a good optimizing compiler of conventional design a

ISSN:0038-0644    

DOI:10.1002/spe.4380240104

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractExperimental results are given for the application of a newn‐gram algorithm to substring searching in DNA strings. The results confirm theoretical predictions of expected running times based on the assumption that the data are drawn from a stationary ergodic source. They also confirm that the algorithms tested are the most efficient known for searches involving larger pattern

ISSN:0038-0644    

DOI:10.1002/spe.4380240105

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractIn this paper we provide efficient algorithms for converting between timestamp values that signify some number of seconds from an arbitrary origin, and character strings specifying Gregorian dates, such as ‘January 1, 1993’. We give several algorithms that explore a range of time and space trade‐offs. Unlike previous algorithms, those discussed here have a constant time cost over a greatly extended range of timestamp values. These algorithms are especially useful in operating systems and in database management sy

ISSN:0038-0644    

DOI:10.1002/spe.4380240106

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper describes the issues involved in sharing data among processes executing co‐operatively in a heterogeneous computing environment. In a heterogeneous environment, the physical representation of a data object may need to be transformed when the object is moved from one type of processor to another. As a part of a larger project to build a heterogeneous distributed shared memory system we developed an automated tool for generating the conversion routines that are used to implement representation conversion for data objects. We developed a novel method for processing source programs that allowed us to extract detailed information about the physical representation of data objects without access to the source code of the compilers that were generating those representations. A performance comparison with the more general XDR heterogeneous data conversion package shows that the customized conversion routines that we generate are 4 to 8 times faste

ISSN:0038-0644    

DOI:10.1002/spe.4380240107

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY

ISSN:0038-0644    

DOI:10.1002/spe.4380240101

出版商:John Wiley&Sons, Ltd.    

年代:1994

数据来源: WILEY