Embedded Cross-debugging Techniques

Cross debugger is a crucial tool for developers in embedded systems domain. It provides the facilities to control and introspect into other running programs, which is important to the programmer to find where the bug is, and then fixes the bug. As a debugger for cross development environment, not only cross debugger has traditional debugger's features such as breakpoint, variable inspecting, etc. but also it should provide many cross facilities, for example, remote downloading, remote controlling, and every command from the host will be parsed and executed by the debugger agent in the target. This thesis discloses the magic of cross debugger's theory and its design principles, also with the implementations and details internals. In this paper, we research the cross debugger's working principles firstly. After the theory, the architecture of target debugger agent is provided. It's the core of a cross debugger. And we research the debugger agents with a cross view both in kernel and application levels. From the design and implementation of debugger agents, the cross functions processing internals such as dynamic downloading, remote breakpoint, registers display are discussed exactly. Also, this paper discusses many other debugging methods in embedded system. Especially, we implements JTAG-debugger for ARM7 CPU. We design it with a multi-arch framework so the cross debugger has the capability to provide multi-architecture. As a result, the cross debugger designed in this paper facilitates our Lab's embedded system development projects. And it is also to be a important component of the Lab's 863 National Project-"Intelligent PDA Mobile Phone with Embedded Linux". There are many problems in Embedded system development domain, as the real-time systems, distributed systems and SOC grow with a rapid speed. For the time's resean, we don't discuss much aoubt that. But it's important to guide the debugger researcher's further work.