preempt : 搶佔

每個任務都有４種狀態：分別是:

1. 執行態，
2. 就緒態,
3. 等待態,
4. 不活動態

來自<RL-ARM 實時庫使用者指南.chm>

next_TCB->state = READY;
rt_put_prio (&os_rdy, next_TCB);

重點研究一下 ，其中的 優先順序 連結串列 list

rt_init_context (&os_idle_TCB, 0, os_idle_demon);

os_idle_demon任務的優先順序為0
init任務的優先順序為1
phaseA任務的優先順序為1

rt_free_box (mp_tcb, os_tsk.run);

struct OS_TSK os_tsk;
typedef struct OS_TSK {
P_TCB run; /* Current running task /
P_TCB new; / Scheduled task to run */
} *P_TSK;

int rt_free_box (void *box_mem, void *box)

參考:nu-lb-nuc140 RTX 流程 分析（二）

os_evt_wait_and (0x0001, 0xffff);
#define os_evt_wait_and(wflags,tmo) _os_evt_wait((U32)rt_evt_wait,wflags,tmo,__TRUE)
extern OS_RESULT _os_evt_wait(U32 p, U16 wait_flags, U16 timeout,
BOOL and_wait) __SVC_0;

OS_RESULT rt_evt_wait (U16 wait_flags, U16 timeout, BOOL and_wait)

rt_evt_wait(0x0001, 0xffff,__TRUE)

rt_system.c

/--------------------------- rt_systick ------------------------------------/

void rt_systick (void) {
/* Check for system clock update, suspend running task. */
P_TCB next;

os_tsk.run->state = READY;
rt_put_rdy_first (os_tsk.run);

/* Check Round Robin timeout. */
rt_chk_robin ();

/* Update delays. */
os_time++;
rt_dec_dly ();

/* Check the user timers. */
rt_tmr_tick ();

/* Switch back to highest ready task */
next = rt_get_first (&os_rdy);
rt_switch_req (next);
}

os_dly 解析

struct OS_XCB os_dly;

(稍後補充)