Semantic analysis is the focus of compilation. In semantic analysis, we should not only check the semantic consistency of the program context, but also provide enough information for the generation of the target code. This paper introduces the realization method of ATLAS semantic analysis, and briefly introduces the realization technology of ATLAS system and the realization method of running environment.
For the special problems that need to be solved in the semantics of atlas, we adopt object-oriented technology to realize them and achieve good results. The concrete implementation adopts the method of combining static semantic analysis with dynamic semantic analysis. This paper also briefly introduces the equipment management system and running environment system in ATLAS system, which lays the foundation for the further development of ATLAS system.
catalogue
The first chapter introduces the system.
Introduction to Atlas System 1. 1
C/ATLAS is the abbreviation of universal/abbreviated test language for all systems. It is a very powerful system-wide standard test language, which is widely used in military and aviation fields.
In the 1960s, ARINC sponsored the development of a test language ATLAS, which was used to test the electronic equipment system on the airplane, which at that time meant the abbreviation test language for avionics system. Subsequently, the US Army, Navy, Air Force and North Atlantic Treaty Organization also joined in the development of this language.
1976, the control of C/ATLAS was transferred from ARINC to IEEE. At this time, the meaning of ATLAS is more extensive: the abbreviation test language of all systems. At the same time, ARINC released the standard ARINC4 16- 13A in IEEE format. 1988. IEEE published ATLAS7 16- 1988/9, and ARINC also published ARINC626- 1988/9 in the same year. After that, IEEE and ARINC updated their standards every three or four years. In 2000, IEEE released ATLAS2000, the latest version of C/ATLAS, and we realized the system.
C/ATLAS has the following characteristics:
First of all, it is a standard testing language. In order to prevent the language from becoming larger and larger, which is not conducive to maintenance, IEEE is responsible for issuing corresponding standards for the language, so as to achieve the standardization and unification of the language. The main users participating in the standards are the US Department of Defense, the German Ministry of Defense, the French Ministry of Defense, the British Ministry of Defense, the Swedish Ministry of Defense and aviation radio companies in the aviation industry.
Second, C/ATLAS is independent of test equipment and can be applied to all test systems. The program written in ATLAS language can test all kinds of instruments and equipment, and the test code does not contain any hardware information used in the test. That is to say, as long as the automatic test equipment (ATE) used for testing supports ATLAS, the ATLAS program written in another test system can be used without modification.
Third, ATLAS is very powerful, providing a truly automated test. In previous tests, testers should not only consider the test algorithm and process, but also spend a lot of energy to choose the equipment used in the test and even design the hardware needed for the test. Different tests need different test equipment and corresponding test flow. In ATLAS, testers do not need to consider testing hardware, but are automatically processed by ATLAS system. In this way, testers can focus more on the design of test algorithm and test flow. ATE in ATLAS system provides a large number of test equipment, and one ATE can carry out multiple tests, which not only simplifies the scale of the test system, but also greatly improves the efficiency and level of testing.
1. 1. 1 hardware environment tested by ATLAS.
ATLAS language can be used to test all kinds of electronic and non-electronic instruments and equipment. With the continuous development of test technology and test equipment, ATLAS language is constantly being modified. On the basis of following IEEE standards, in order to facilitate users' use, ATLAS itself provides a new extension mechanism to complete the tests that cannot be carried out due to the limitations of current standards.
ATLAS language does not provide test hardware information. In the process of user's use, ATLAS system automatically allocates devices and calls corresponding hardware operations to complete the UUT (Unit Under Test) test according to the device feature information in the program. It can be said that ATLAS system is a virtual machine for managing and testing software and hardware, which is not only responsible for compiling ATLAS source program and generating machine code; It is also necessary to manage the test resource equipment, including: adding and deleting equipment, managing the switch connection path from the unit under test (UUT) to the automatic test system (ATE) equipment; In addition, ATLAS system should handle the events during the test and monitor the work of test resources.
The following figure shows the hardware environment of ATLAS test.
Hardware structure diagram of ATLAS test system
ATLAS test system hardware mainly consists of the following parts:
ATE(auto test equipment): Automatic test equipment, which enables the core of the whole test system to connect the equipment to the host using VXI or IEEE488 bus. The equipment in the ATE cabinet mainly includes: 1) resources for testing, such as various controllable DC power supplies, controllable signal generators, digital multimeters, oscilloscopes, etc. 2) Switching equipment, which is used to connect the array interface outside the ATE and the equipment inside the ATE. 3)ATE array interface is the output interface of ATE, which is connected with the adapter for testing.
UUT (unit under test): The unit under test, that is, the object under test, is connected with the adapter outside ATE during the test.
Adapter: used to connect ATE and UUT. During the test, ATE is responsible for supplying power to UUT (unit under test), inputting excitation signals and reading the contents of test points from UUT (unit under test). The function of the adapter is to establish the corresponding connection between ATE (Automatic Test Equipment) and UUT, and carry out electrical conversion, electrical signal to non-electrical signal conversion, etc. According to UUT conditions.
VXI bus, etc. Used to connect the host computer with the test equipment and controllable switch in ATE (Automatic Test Resource) for ATE control and data communication.
Host: Test host on which ATLAS system runs.
1. 1.2. Atlas system structure
ATLAS system is responsible for compiling and executing the test program written by ATLAS, providing debugging environment, testing simulation environment and managing various devices and switches in ATE. ATLAS system consists of ATLAS compiler, ATLAS running environment, ATLAS environment management program, equipment library, extended protocol, bus description file, equipment description file, switch description file and adapter description file.
The structure of the system is shown in the following figure:
ATLAS system test flow chart
ATLAS environmental management program converts the device description file, switch description file, bus description file and adapter description file used in the test into internal device information, switch information, bus information and adapter pin information.
ATLAS compiler compiles the test program into executable object code and gives it to ATLAS operating system for execution. During the compilation process, ATLAS compiler allocates test equipment according to the equipment information, switch information, bus and adapter pin information in the system, generates the operation code of the corresponding test equipment, and recycles the equipment after the test.
ATLAS operating system is responsible for executing the target code and completing the final test. In the operating system, it is necessary to monitor the execution of equipment, handle the signals and interrupts from test equipment, manage the process of test execution, and provide the corresponding debugging environment for programmers.
During the execution, ATLAS operating system calls the device functions in the device DLL library to perform the test. The equipment management system is responsible for adding test equipment, modifying switch paths, modifying test equipment information and deleting test equipment. Adding and modifying devices will modify the device DLL library accordingly.
ATLAS compiler searches for devices according to the feature information of devices in the source program, combined with device information, pin information and switch information inside the system. If it finds a device that meets the conditions, it allocates the device and calls the operation of the device. If it changes the equipment of the system, such as adding new equipment or modifying some information of the current equipment, it needs to modify the equipment information inside the system so that it can find qualified equipment when compiling the atlas.
1.2 the work completed in this paper
The work introduced in this paper is a part of our project-ATLAS system, mainly the semantic analysis part of Atlas language. The formal semantics, compilation environment, running environment, dynamic semantic analysis technology and static semantic analysis technology of atlas are given. The work accomplished in this paper is as follows:
The semantic analysis of ATLAS language is realized.
Using object-oriented technology [5] and [6], the semantic expansion and equipment independence of atlas requirements are solved.
This paper expounds the composition of ATLAS system and the functions of each part.
The semantic analyzer of ATLAS is implemented [7], and the contents of static semantic check and dynamic semantic check of ATLAS are given, which are described by attribute grammar.
Chapter II Atlas Language
2. 1 Atlas 2000
ATLAS is a very interesting language. Unlike ordinary process languages, ATLAS is closer to natural languages. In this language, each sentence consists of verbs, nouns and their modifying information, and an atlas sentence contains at least one verb and one noun [2].
ATLAS2000 statement structure is shown in the following figure:
Fixed domain separator
,
The flag field in the fixed field is used to explain the meaning of this statement. If the flag is ignored, it is a normal statement, and if it is a comment statement, it is marked as "C" or "B". If it is "e", it means that you can start the test from this marked statement, regardless of the previous test.
Verb verbs include verbs and verb modifiers in ATLAS. Verbs include: apply, define, declare, demand, disconnect, remove, execute, etc. Verb modifiers are used to assist verbs, such as "do at the same time" in sentences and "then reset" in signal sentences.
Separator, in ATLAS, different grammatical components are separated by the separator ",".
Each entry has a terminator "$".
The rest of each sentence depends on the situation.
ATLAS2000 structure:
ATLAS2000 is a multi-layer language [4]. An ATLAS program consists of core primitives, sentences, models, TTF and modules. ATLAS core components and ATLAS primitives form the basis of this language, and users can establish the requirements of test items through predefined and these basic morphemes. The model structure enables users to combine the operations of the underlying components. Abstract higher-level structure and describe more complex test functions. TTF(Test Technology Frameworks) test technical framework, ATLAS2000 test technical framework includes and defines some special test environments based on ATLAS2000. This module is used to encapsulate those reusable test codes. The specific structure is shown in the following figure:
ATLAS 2000 structure diagram
Precautions:
ATLAS NUCLEUS defines the typical performance and function of ATLAS language, which consists of three parts: formal grammar, reserved words and rules.
ATLAS primitive is the basic element to describe and explain ATLAS signal, action, attribute and performance. These basic elements can no longer be divided, including nouns, noun modifiers, verbs, verb modifiers, operators and their functional definitions.
ATLAS model is a representation of a series of functions and processes. In ATLAS, the model is used to describe the characteristics (UUT) of the test equipment and the unit under test. Atlas model is the description basis of grammatical elements, and atlas keywords are defined according to ATLAS2000 model. All keywords must be modeled. Once a model is defined and becomes a part of the Test Technology Framework (TTF), it can be used as a keyword in ATLAS statements.
The module of ATLAS is an entity contained in ATLAS program, which can be said to be a container containing ATLAS process and non-ATLAS process. This module is used in ATLAS with an "include" statement. In the module, the scope of the process is determined by declaring whether the attribute of the process is global or local, and the global process can be used outside the module. All processes defined in this module can be used inside the module, and other modules can also be used outside.
2.2 Atlas semantic analysis function
ATLAS language is the standard language for testing. Although there is no specific information about the hardware of the test equipment in ATLAS, such as the physical address of the equipment, the device driver, the operating function of the equipment, etc., ATLAS provides primitives and models to describe the characteristics of the equipment [1][3], including nouns, verbs, modifiers, connections and signal reserved words. ATLAS compiler is based on the information composed of these primitives and models in ATLAS program.
Compared with common programming languages, the biggest feature of ATLAS is that it contains some information and sentences related to test equipment or unit under test [1], and operating test equipment is an important part of ATLAS semantics. Now let's compare how non-ATLAS language and ATLAS language write test programs.
Let's compare the test program written in C language with the program with the same function written in ATLAS language.
Example: Connect a DC power supply with a voltage of 28v to the device under test (UUT).
Realization:
The specific operation steps of writing a test program in C language are: first, turn on the power supply to the test system, set the switch from the power supply to UUT as connection, then set the power supply voltage to 28V, then check whether the output voltage of the power supply is 28V and the working current is less than 1A, and allow the power supply to work if the conditions are met.
In ATLAS, all these operations can be done in a simple sentence. In ATLAS program, we don't need to point out which power supply to use. You can see the difference between ATLAS and C language. In the C program, the tester specifies the power supply to be used, turns on the switch of the power supply, and completes the test. In ATLAS, these tasks are completed automatically by the compiler.
The code written in C language and ATLAS language is compared as follows:
Excerpt from: softlab.jlu.edu.cn/temp/thesis/2004liulei.doc