15 research outputs found
On the expressiveness of single-pass instruction sequences
We perceive programs as single-pass instruction sequences. A single-pass
instruction sequence under execution is considered to produce a behaviour to be
controlled by some execution environment. Threads as considered in basic thread
algebra model such behaviours. We show that all regular threads, i.e. threads
that can only be in a finite number of states, can be produced by single-pass
instruction sequences without jump instructions if use can be made of Boolean
registers. We also show that, in the case where goto instructions are used
instead of jump instructions, a bound to the number of labels restricts the
expressiveness.Comment: 14 pages; error corrected, acknowledgement added; another error
corrected, another acknowledgement adde
Indirect jumps improve instruction sequence performance
Instruction sequences with direct and indirect jump instructions are as
expressive as instruction sequences with direct jump instructions only. We show
that, in the case where the number of instructions is not bounded, we are faced
with increases of the maximal internal delays of instruction sequences on
execution that are not bounded by a linear function if we strive for acceptable
increases of the lengths of instruction sequences on elimination of indirect
jump instructions.Comment: 10 pages, definition of maximal internal delay and theorem 1 are
stated more precise; presentation improve
Putting Instruction Sequences into Effect
An attempt is made to define the concept of execution of an instruction
sequence. It is found to be a special case of directly putting into effect of
an instruction sequence. Directly putting into effect of an instruction
sequences comprises interpretation as well as execution. Directly putting into
effect is a special case of putting into effect with other special cases
classified as indirectly putting into effect
On the behaviours produced by instruction sequences under execution
We study several aspects of the behaviours produced by instruction sequences
under execution in the setting of the algebraic theory of processes known as
ACP. We use ACP to describe the behaviours produced by instruction sequences
under execution and to describe two protocols implementing these behaviours in
the case where the processing of instructions takes place remotely. We also
show that all finite-state behaviours considered in ACP can be produced by
instruction sequences under execution.Comment: 36 pages, consolidates material from arXiv:0811.0436 [cs.PL],
arXiv:0902.2859 [cs.PL], and arXiv:0905.2257 [cs.PL]; abstract and
introduction rewritten, examples and proofs adde
arXiv:0909.2089v1 [cs.PL] 11 Sep 2009
Abstract. Instruction sequences with direct and indirect jump instructions are as expressive as instruction sequences with direct jump instructions only. We show that, in the case where the number of instructions is not bounded, there exist instruction sequences of the former kind from which elimination of indirect jump instructions is possible without a super-linear increase of their maximal internal delay on execution only at the cost of a super-linear increase of their length
Bitcoin and Islamic Finance
It is argued that a Bitcoin-style money-like informational commodity may constitute an effective instrument for the further development of Islamic Finance. The argument involves the following elements: (i) an application of circulation theory to Bitcoin with the objective to establish the implausibility of interest payment in connection with Bitcoin, (ii) viewing a Bitcoin-like system as a money-like exclusively informational commodity with the implication that such a system need not support debt, (iii) the idea that Islamic Finance imposes different requirements compared to conventional financial policies on a money concerning its use as a tool for achieving social and economic objectives, and (iv) identification of two aspects of mining, gambling and lack of trust, that may both be considered problematic from the perspective of compliance with the rules of Islamic Finance and a corresponding proposal to modify the architecture of mining in order to improve compliance with these rules
A short introduction to program algebra with instructions for Boolean registers
A parameterized algebraic theory of instruction sequences, objects that
represent the behaviours produced by instruction sequences under execution, and
objects that represent the behaviours exhibited by the components of the
execution environment of instruction sequences is the basis of a line of
research in which issues relating to a wide variety of subjects from computer
science have been rigorously investigated thinking in terms of instruction
sequences. In various papers that belong to this line of research, use is made
of an instantiation of this theory in which the basic instructions are
instructions to read out and alter the content of Boolean registers and the
components of the execution environment are Boolean registers. In this paper,
we give a simplified presentation of the most general such instantiated theory.Comment: 21 pages, this paper is to a large extent a compilation of material
from several earlier publications; 23 pages, presentation improved and
section on uses for the theory added. arXiv admin note: text overlap with
arXiv:1702.0351