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os_core.c contains core functionality for µC/OS-III such as OSInit() to initialize µC/OS-III, OSSched() for the task level scheduler, OSIntExit() for the interrupt level scheduler, pend list (or wait list) management (see Pend Lists), ready list management (see Ready List in General Statistics - Run-Time), and more.
os_dbg.c contains declarations of constant variables used by a kernel aware debugger or µC/Probe.
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os_pend_multi.c contains the code to allow code to pend on multiple semaphores or message queues. This is described in Pending On Multiple Objects API Calls.
os_prio.c contains the code to manage the bitmap table used to keep track of which tasks are ready-to-run, see The Ready List. This file can be replaced by an assembly language equivalent to improve performance if the CPU used provides bit set, clear and test instructions, and a count leading zeros instruction.
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os_tick.c contains code to manage tasks that have delayed themselves or that are pending on a kernel object with a timeout. See Chapter 5 About Task Management.
os_time.c contains code to allow a task to delay itself until some time expires. See Time Management.
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