Jeong-Han Yun

Refining schizophrenia via graph reachability in esterel

Esterel is an imperative synchronous language for control-dominant reactive systems. The combination of imperative structures and the perfect synchrony hypothesis often result in schizophrenic statements. Previous studies explain the characteristics of schizophrenia as the instantaneous reentrance to block statements: local signal declarations and parallel statements. In practice, however, most instantly-reentered block statements do not cause any problems in Esterel compilation. In this paper, we refine schizophrenic problems in terms of signal emissions, and suggest an algorithm to detect harmful schizophrenia using reachability on control flow graphs (CFGs) in Esterel. Our algorithm performs well in analyzing practical programs. Moreover, it can be easily applied to existing compilers.

Automatic Hardware/Software Interface Generation for Embedded System

A large portion of the embedded system development process involves the integration of hardware and software. Unfortunately, communication across the hardware/software boundary is tedious and error-prone to create. This paper presents an automatic hardware/software interface generation system. As the front-end of hardware/software co-design frameworks, a system designer defines XML specifications for hardware functions. Our system generates hardware/software interfaces including Device Driver, Driver API, and Device Controller from these specifications. Embedded software designers can easily use hardware just like system libraries. Our system reduces the mistakes and errors that can be occurred when a software programmer directly connects software to hardware, and supports balancing labors between hardware developers and software programmers. Moreover, this system can be used as the back-end for a hardware/software co-design framework.

Detection of harmful schizophrenic statements in esterel

In imperative synchronous languages, a statement is called schizophrenic if it is executed more than once in a single clock. When a schizophrenic statement is translated into a circuit, the circuit can behave abnormally because of the multiple executions. To solve the problems caused by schizophrenic statements, compilers duplicate the statements to avoid multiple executions. Esterel is an imperative synchronous language. Schizophrenic statements in Esterel are considered to occur due to the instantaneous reentrance of local signal declarations or parallel statements. However, if the corresponding circuit of a schizophrenic statement behaves normally, it is harmless and thus curing is not necessary. In this paper, we identify the conditions under which a schizophrenic statement of the Esterel program must be cured during circuit translation. We also propose an algorithm to detect schizophrenic statements that have to be cured on the control flow graphs (CFGs) of source codes. Our algorithm detects all schizophrenic statements that have to be cured and results in fewer false alarms on the benchmark programs used in the previous work. It is simple and based on the CFG of a program, implying that it can be merged into existing compilers easily.

Automatic generation of hardware/software interface with product-specific debugging tools

Software programmers want to manage pure software, not hardware-software entanglements. Unfortunately, traditional development methodologies cannot clearly separate hardware and software in embedded system development process. We propose a Hardware/software INterface GEnerator; we call it HINGE. After receiving device specifications including device usage rules for each device, HINGE automatically generates device API, device driver, and device controller for each device. In addition, HINGE equips device APIs to check the device usage rules at run-time. Consequently, HINGE gives support to not only fast prototyping but also device usage rule-debugging in embedded software