Browsing by Author "Chen, Cheng-Yang"

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Hardwiring the OS Kernel into a Java Application Processor
(2017-01-01)
Tsai, Chun-Jen
;
Lin, Cheng-Ju
;
Chen, Cheng-Yang
;
Lin, Yan-Hung
;
Ji, Wei-Jhong
This paper presents the design and implementation of a hardwired OS kernel circuitry inside a Java application processor to provide the system services that are traditionally implemented in software. The hardwired system functions in the proposed SoC include the thread manager, the memory manager, and the I/O subsystem interface. There are many advantages in making the OS kernel a hardware component, such as a fast system boot time, highly efficient single-core multi-thread context-switching performance, and a better potential for supporting a complex multi-level memory subsystem. In addition, since the target application processor used in this paper is based on a Java processor, the system is not susceptible to the stack and pointer-based security attacks that are common to the register-based processors. Full-system performance evaluations on an FPGA show that the proposed system is very promising for deeply-embedded multi-thread applications.
JAIP-MP: A Four-Core Java Application Processor for Embedded Systems
(2016)
Tsai, Chun-Jen
;
Wu, Tsung-Han
;
Su, Hung-Cheng
;
Chen, Cheng-Yang
;
資訊工程學系
In this chapter, we present a four-core Java application processor, JAIP-MP. In addition to supporting multi-core coherent data accesses to shared memory, each processor core in JAIP-MP is a hardwired Java core that is capable of dynamic class loading, two-fold bytecode execution, object-oriented dynamic resolution, method/object caching, Java exception handling, preemptive multi-threading, and memory management. Most of the essential OS kernel functions are implemented in hardware. In particular, the preemptive multi-threading performance is much higher than that of a software-based VM running on a traditional OS kernel such as Linux. Currently, single-cycle context switching with a time quantum as small as 20 mu s can be achieved by each core. More importantly, the Java language model itself makes it possible to maintain binary portability of application software regardless of the hardwired OS kernel component. In summary, JAIP-MP could be used to study the potential benefits of OS kernel implementation in hardware.