Taizo Kojima

A system for building interactive visual simulator of digital hardware

A digital system software simulator can provide high level support for testing and debugging of firmware using graphical user interfaces which perform visualization of the hardware model. Since sufficient knowledge of the target hardware is required for the development of a simulator, a simulator is usually developed by a hardware engineer, even though the hardware engineer may not have enough knowledge for building interactive graphical user interfaces. Therefore, it is not easy for a hardware engineer to develop a visual simulator using graphical user interfaces. In this paper, a new system for building interactive visual simulators and an example of its application are presented. In this system, an object-oriented simulator kernel is introduced for separation of hardware description and user interface implementation. This kernel is built based on an object-oriented method, and it provides common functions for hardware modeling and user interfaces, such, as an event driven mechanism. Layered on this kernel, an object-oriented hardware description language and a user interface description language are implemented. By this approach, both hardware descriptions and user interfaces have a high level software reusability. Therefore, a hardware engineer can develop an interactive visual simulator by describing only the hardware model. Furthermore, by using user interface description language, a hardware engineer can customize a graphical user interface according to the purpose of simulation.

ALHARD: an application-oriented language for hardware simulation

For the purpose of the specification and operation level simulations of hardware, hardware description language Alhard (Application-oriented Language for HARDware simulation) was designed, and its simulation system was developed. Alhard language is an application-oriented language to be used for generation of simulators, and is designed by expanding C language to be used for hardware descriptions. Its characteristics are an operation for the bit string, an object oriented feature, and demon function activated by event driven. In this system, by using the demon function, hardware descriptions can be separated from the descriptions of check functions for simulators and user interfaces. Simulations can be executed by converting the hardware description into C language to be compiled. In the simulation systems, visual user interfaces, implemented through use of the demon function, are provided. In this paper, a summary of the system, software structure, language specifications, simulator interfaces, and an example of an application of this system to a micro-program simulator are described.