arXiv subjects

C. A. Middelburg

Publications and source records attributed to C. A. Middelburg.

78 records · Page 5Linked to original sources

arXiv2008

Instruction sequences for the production of processes

Single-pass instruction sequences under execution are considered to produce behaviours to be controlled by some execution environment. Threads as considered in thread algebra model such behaviours: upon each action performed by a thread, a reply from its execution environment determines how the thread proceeds. Threads in turn can be looked upon as producing processes as considered in process algebra. We show that, by apposite choice of basic instructions, all processes that can only be in a finite number of states can be produced by single-pass instruction sequences.

cs.PL↗

arXiv2008

A thread calculus with molecular dynamics

We present a theory of threads, interleaving of threads, and interaction between threads and services with features of molecular dynamics, a model of computation that bears on computations in which dynamic data structures are involved. Threads can interact with services of which the states consist of structured data objects and computations take place by means of actions which may change the structure of the data objects. The features introduced include restriction of the scope of names used in threads to refer to data objects. Because that feature makes it troublesome to provide a model based on structural operational semantics and bisimulation, we construct a projective limit model for the theory.

cs.LO↗

arXiv2008

Thread algebra for poly-threading

Threads as considered in basic thread algebra are primarily looked upon as behaviours exhibited by sequential programs on execution. It is a fact of life that sequential programs are often fragmented. Consequently, fragmented program behaviours are frequently found. In this paper, we consider this phenomenon. We extend basic thread algebra with the barest mechanism for sequencing of threads that are taken for fragments. This mechanism, called poly-threading, supports both autonomous and non-autonomous thread selection in sequencing. We relate the resulting theory to the algebraic theory of processes known as ACP and use it to describe analytic execution architectures suited for fragmented programs. We also consider the case where the steps of fragmented program behaviours are interleaved in the ways of non-distributed and distributed multi-threading.

cs.LO↗

arXiv2008

Programming an interpreter using molecular dynamics

PGA (ProGram Algebra) is an algebra of programs which concerns programs in their simplest form: sequences of instructions. Molecular dynamics is a simple model of computation developed in the setting of PGA, which bears on the use of dynamic data structures in programming. We consider the programming of an interpreter for a program notation that is close to existing assembly languages using PGA with the primitives of molecular dynamics as basic instructions. It happens that, although primarily meant for explaining programming language features relating to the use of dynamic data structures, the collection of primitives of molecular dynamics in itself is suited to our programming wants.

cs.PL↗

arXiv2007

Instruction sequences with indirect jumps

We study sequential programs that are instruction sequences with direct and indirect jump instructions. The intuition is that indirect jump instructions are jump instructions where the position of the instruction to jump to is the content of some memory cell. We consider several kinds of indirect jump instructions. For each kind, we define the meaning of programs with indirect jump instructions of that kind by means of a translation into programs without indirect jump instructions. For each kind, the intended behaviour of a program with indirect jump instructions of that kind under execution is the behaviour of the translated program under execution on interaction with some memory device.

cs.PL↗

arXiv2007

Program algebra with a jump-shift instruction

We study sequential programs that are instruction sequences with jump-shift instructions in the setting of PGA (ProGram Algebra). Jump-shift instructions preceding a jump instruction increase the position to jump to. The jump-shift instruction is not found in programming practice. Its merit is that the expressive power of PGA extended with the jump-shift instruction, is not reduced if the reach of jump instructions is bounded. This is used to show that there exists a finite-state execution mechanism that by making use of a counter can produce each finite-state thread from some program that is a finite or periodic infinite sequence of instructions from a finite set.

cs.PL↗