git-svn-id: https://rt-thread.googlecode.com/svn/trunk@657 bbd45198-f89e-11dd-88c7-29a3b14d5316
rt_hw_context_switch() rt_hw_interrupt_disable() rt_hw_interrupt_enable() git-svn-id: https://rt-thread.googlecode.com/svn/trunk@654 bbd45198-f89e-11dd-88c7-29a3b14d5316
git-svn-id: https://rt-thread.googlecode.com/svn/trunk@620 bbd45198-f89e-11dd-88c7-29a3b14d5316