Abstract
"Development of methods of decomposition of algorithm for realization in systems on chip "
The composer: Aniskin S.V.
The principle of microprogram management has been offered in 1951 by M. Wilks and assumes presence in any digital system of device management (MD) which coordinates all blocks of system. The executive part of system which carries out data processing, refers to the operational automatic device (ÎÀ), and the digital system as a whole refers to as the operational device. The algorithm of work of system is set by one of formal methods, in practice of engineering designing flowcharts is most widely used.
In operational tops flowchart sets of microoperations Yt, where Y = {y1 enter the name..., yn} - set of microoperations which initiate the set kind of data processing in ÎÀ.
In conditional tops flowchart logic conditions Xt, where X = {x1 enter the name..., xL} - set of initial signals ÎÀ which identify a condition of processing information.
The algorithm of system management is set by a code of management which acts in MD from an environment. The algorithm of management ÎÀ refers to as the microprogram, whence and the name of a principle of M. Wilks has gone.
So, we have the flowchart which consists of two independent devices. We can replace both DM, and ÎÀ not destroying work capacity of system, under conditions of preservation of the report of interaction (signals can have other value, but their quantity should be kept). For example, is an opportunity to use the same the operating device for different processes (under condition of similarity of algorithm of work) or to replace it with another (at change of conditions of course of technological process).
In connection with a wide circulation CPLD there were greater opportunities at construction of operating automatic devices. The table of coding of DM conditions "is sewn up" in CPLD, thus there is an opportunity of repeated rewriting. Use CPLD imposes additional restrictions on the size of the coding table, for example, in systems which are used in the industry, the quantity of conditions can be measured by thousand and frequently it is impossible to sew up all automatic device in CPLD. Therefore there is a necessity for splitting the microprogram on separate parts which satisfy to restrictions from CPLD, not breaking algorithm.
The purpose of the given work is improvement and development of new methods of microprogram algorithm to satisfaction the restrictions imposed from CPLD. The choice of this task has been caused by that all modern methods of synthesis are not optimized, and completions are necessary by development of digital automatic devices. That is, by development of more complex flowcharts of Mile automatic devices, there is no universal remedy of the description of synthesis by complex structure. In any case it will be necessary to do many tests and checks.
The primary goals of work consist in the following:
· Studying existing methods of decomposition of algorithm of the microprogram.
· Development new methods on the basis of the studied methods and their testing.
· Creation of the visual environment to flowchart editing, using UML
It is planned to develop the software which would provide synthesis and development of flowcharts of operating and final automatic devices, using existing high technologies, such as UML, FPGA. Practical value of a product consists in methods of the approach to the designing, connected with new methods of automatic device structure optimization, and also availability of a program code of a product and an opportunity of its updating.
Presence of editors FSM testifies to a urgency of a theme of final automatic devices (AD) (finite state machine) in such products as AHDL and Riviera. The Most widespread among languages of the description of the equipment are languages VHDL and Verilog. However direct realization of operating automatic devices in these languages is labour-intensive process. Therefore the special tools have been included in structure of many foreign ÑÀÏÐ, allowing to simplify development of operating automatic devices. So module FSM is included in structure SAPR Active - HDL firms Aldec. This module possesses the multipurpose graphic interface, for the description of operating automatic devices. However module FSM possesses a number of lacks. In particular, the form of record of the operating automatic device demands knowledge of language HDL. Systems of designing of operating automatic devices and in others ÑÀÏÐ are In a similar way organized.
Also FSM models at generation of a code do not consider hardware expenses at generation ðåçóëüòèðóþùåãî a code as it will be necessary that it is made by means of synthesis, but the generated code does not consider many features of realization of structure of the automatic device, therefore means of synthesis often give out not the most optimum configuration ðåçóëüòèðóþùåãî devices.
Lack of FSM-editor A - HDL - generation of a program code in behavioural style that makes impossible to predict result of synthesis. The structural description of the scheme received as a result of trivial realization, enables predictions of results even before synthesis - at a stage of generation of a program code that enables to generate a code for a crystal or numbers of gates FPGA of the set dimension.
As to UML editors for final automatic devices one of such development is executed graphic language on the basis of SWITCH-technologies and UML-notations - UniMod which describes behaviour of object by means of ãðàôîâ transitions of structural automatic devices with the notation, and columns of transitions are under construction by means of the notation of the diagram of conditions UML.
Package UniMod provides development and performance of the àâòîìàòíî-focused programs. It allows to create and edit UML - diagrams of classes and conditions which correspond to the scheme of communications and the column of transitions, and supports two types of realization - on the basis of interpretation and compilation.
In the first case there is an opportunity:
· To transform diagrams to format XML;
· To execute the received XML-description by means of the interpreter created on the basis of a set of developed base classes. These classes realize, for example, such functions as processing of events, preservation of a current condition, recording.
In the second case of the diagram it will directly be transformed to a code in the target programming language which subsequently is compiled and started.
Designing of programs with use of package UniMod assumes the following approach: the logic of the appendix is described by the structural final automatic device set in the form of a set specified above diagrams, constructed with use of the UML-notation. Sources of events and objects of management are set by a code in the target programming language.
One of UML the editors allowing partially to realize a task in view, is Poseidon. It is convenient the interface and generates comprehensible ðåçóëüòèðóþùèé a code, but its lack that the given software product has the paid license and the closed program code that makes impossible its updating in a necessary direction.
To one more UML the editor is UMLet constructed group of developers on the basis of platform Eclipse, development covers all UML.
Necessity of program realization of structural code generation methods of flowchart-automatic devices and application of optimization of this code follows from the analysis of existing problems and requirements.
The software product should possess the set forth above advantages (generation of a structural code on set the column, calculation of the demanded area of a crystal, etc.).
During the analysis of methods of optimization and constant expansion of their number there are certain requirements to realization of software product, the certain structure is formed.
The developed system should consist of following parts:
· The Graphic editor who realizes an opportunity of graphic display, editing and creations demanded flowcharts (FSM).
· The Compiler which enables preservations of flowcharts in internal language of the program (XML, XMI, etc.).
· Optimize the flowchart of the automatic device proceeding from restrictions of CPLD
Result of work will be the software, with the open code and realizing generation of a code of the microprogram of the automatic device, after its decomposition. The program code will be generated in view of existing algorithms of optimization of operating automatic devices and CPLD is specified under concrete. Entrance parameters for PP will be UML the flowchart of realization of the operating automatic device.
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