嵌入式平台pxa270下多线程调用，经典的示例源码

实现linux下1、文件的拷贝；2、运行3个多线程任务、3、添加一个新的系统调用。,implement under linux environment:1. copy of files 2. run 3 multi-thread application 3. add a new system_call.

可模拟实现Linux用户级线程库的静态调用,规避了多线程库的竞态条件和复杂的同步问题.除源代码外还有详细的设计说明文档.-Can simulate the realization of Linux user-level Thread Library static call circumvented competing multi-threaded library condition and complex synchronization problems. In addition to sour

nachos虚拟操作系统project,userprog实现调用执行客户程序，添加process.cc/.h支持多进程多线程调用-nachos： virtual operating system project, userprog called to perform client program, add process.cc/.h to support multi-process multi-threaded calls