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os_task.c
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1 /*
2 *********************************************************************************************************
3 * uC/OS-II
4 * The Real-Time Kernel
5 * TASK MANAGEMENT
6 *
7 * (c) Copyright 1992-2009, Micrium, Weston, FL
8 * All Rights Reserved
9 *
10 * File : OS_TASK.C
11 * By : Jean J. Labrosse
12 * Version : V2.89
13 *
14 * LICENSING TERMS:
15 * ---------------
16 * uC/OS-II is provided in source form for FREE evaluation, for educational use or for peaceful research.
17 * If you plan on using uC/OS-II in a commercial product you need to contact Micrim to properly license
18 * its use in your product. We provide ALL the source code for your convenience and to help you experience
19 * uC/OS-II. The fact that the source is provided does NOT mean that you can use it without paying a
20 * licensing fee.
21 *********************************************************************************************************
22 */
23 
24 #ifndef OS_MASTER_FILE
25 #include <ucos_ii.h>
26 #endif
27 
28 /*$PAGE*/
29 /*
30 *********************************************************************************************************
31 * CHANGE PRIORITY OF A TASK
32 *
33 * Description: This function allows you to change the priority of a task dynamically. Note that the new
34 * priority MUST be available.
35 *
36 * Arguments : oldp is the old priority
37 *
38 * newp is the new priority
39 *
40 * Returns : OS_ERR_NONE is the call was successful
41 * OS_ERR_PRIO_INVALID if the priority you specify is higher that the maximum allowed
42 * (i.e. >= OS_LOWEST_PRIO)
43 * OS_ERR_PRIO_EXIST if the new priority already exist.
44 * OS_ERR_PRIO there is no task with the specified OLD priority (i.e. the OLD task does
45 * not exist.
46 * OS_ERR_TASK_NOT_EXIST if the task is assigned to a Mutex PIP.
47 *********************************************************************************************************
48 */
49 
50 #if OS_TASK_CHANGE_PRIO_EN > 0u
51 INT8U OSTaskChangePrio (INT8U oldprio,
52  INT8U newprio)
53 {
54 #if (OS_EVENT_EN)
55  OS_EVENT *pevent;
56 #if (OS_EVENT_MULTI_EN > 0u)
57  OS_EVENT **pevents;
58 #endif
59 #endif
60  OS_TCB *ptcb;
61  INT8U y_new;
62  INT8U x_new;
63  INT8U y_old;
64 #if OS_LOWEST_PRIO <= 63u
65  INT8U bity_new;
66  INT8U bitx_new;
67  INT8U bity_old;
68  INT8U bitx_old;
69 #else
70  INT16U bity_new;
71  INT16U bitx_new;
72  INT16U bity_old;
73  INT16U bitx_old;
74 #endif
75 #if OS_CRITICAL_METHOD == 3u
76  OS_CPU_SR cpu_sr = 0u; /* Storage for CPU status register */
77 #endif
78 
79 
80 /*$PAGE*/
81 #if OS_ARG_CHK_EN > 0u
82  if (oldprio >= OS_LOWEST_PRIO) {
83  if (oldprio != OS_PRIO_SELF) {
84  return (OS_ERR_PRIO_INVALID);
85  }
86  }
87  if (newprio >= OS_LOWEST_PRIO) {
88  return (OS_ERR_PRIO_INVALID);
89  }
90 #endif
91  OS_ENTER_CRITICAL();
92  if (OSTCBPrioTbl[newprio] != (OS_TCB *)0) { /* New priority must not already exist */
93  OS_EXIT_CRITICAL();
94  return (OS_ERR_PRIO_EXIST);
95  }
96  if (oldprio == OS_PRIO_SELF) { /* See if changing self */
97  oldprio = OSTCBCur->OSTCBPrio; /* Yes, get priority */
98  }
99  ptcb = OSTCBPrioTbl[oldprio];
100  if (ptcb == (OS_TCB *)0) { /* Does task to change exist? */
101  OS_EXIT_CRITICAL(); /* No, can't change its priority! */
102  return (OS_ERR_PRIO);
103  }
104  if (ptcb == OS_TCB_RESERVED) { /* Is task assigned to Mutex */
105  OS_EXIT_CRITICAL(); /* No, can't change its priority! */
106  return (OS_ERR_TASK_NOT_EXIST);
107  }
108 #if OS_LOWEST_PRIO <= 63u
109  y_new = (INT8U)(newprio >> 3); /* Yes, compute new TCB fields */
110  x_new = (INT8U)(newprio & 0x07);
111  bity_new = (INT8U)(1u << y_new);
112  bitx_new = (INT8U)(1u << x_new);
113 #else
114  y_new = (INT8U)((newprio >> 4) & 0x0F);
115  x_new = (INT8U)( newprio & 0x0F);
116  bity_new = (INT16U)(1u << y_new);
117  bitx_new = (INT16U)(1u << x_new);
118 #endif
119 
120  OSTCBPrioTbl[oldprio] = (OS_TCB *)0; /* Remove TCB from old priority */
121  OSTCBPrioTbl[newprio] = ptcb; /* Place pointer to TCB @ new priority */
122  y_old = ptcb->OSTCBY;
123  bity_old = ptcb->OSTCBBitY;
124  bitx_old = ptcb->OSTCBBitX;
125  if ((OSRdyTbl[y_old] & bitx_old) != 0u) { /* If task is ready make it not */
126  OSRdyTbl[y_old] &= ~bitx_old;
127  if (OSRdyTbl[y_old] == 0u) {
128  OSRdyGrp &= ~bity_old;
129  }
130  OSRdyGrp |= bity_new; /* Make new priority ready to run */
131  OSRdyTbl[y_new] |= bitx_new;
132  }
133 
134 #if (OS_EVENT_EN)
135  pevent = ptcb->OSTCBEventPtr;
136  if (pevent != (OS_EVENT *)0) {
137  pevent->OSEventTbl[y_old] &= ~bitx_old; /* Remove old task prio from wait list */
138  if (pevent->OSEventTbl[y_old] == 0u) {
139  pevent->OSEventGrp &= ~bity_old;
140  }
141  pevent->OSEventGrp |= bity_new; /* Add new task prio to wait list */
142  pevent->OSEventTbl[y_new] |= bitx_new;
143  }
144 #if (OS_EVENT_MULTI_EN > 0u)
145  if (ptcb->OSTCBEventMultiPtr != (OS_EVENT **)0) {
146  pevents = ptcb->OSTCBEventMultiPtr;
147  pevent = *pevents;
148  while (pevent != (OS_EVENT *)0) {
149  pevent->OSEventTbl[y_old] &= ~bitx_old; /* Remove old task prio from wait lists */
150  if (pevent->OSEventTbl[y_old] == 0u) {
151  pevent->OSEventGrp &= ~bity_old;
152  }
153  pevent->OSEventGrp |= bity_new; /* Add new task prio to wait lists */
154  pevent->OSEventTbl[y_new] |= bitx_new;
155  pevents++;
156  pevent = *pevents;
157  }
158  }
159 #endif
160 #endif
161 
162  ptcb->OSTCBPrio = newprio; /* Set new task priority */
163  ptcb->OSTCBY = y_new;
164  ptcb->OSTCBX = x_new;
165  ptcb->OSTCBBitY = bity_new;
166  ptcb->OSTCBBitX = bitx_new;
167  OS_EXIT_CRITICAL();
168  if (OSRunning == OS_TRUE) {
169  OS_Sched(); /* Find new highest priority task */
170  }
171  return (OS_ERR_NONE);
172 }
173 #endif
174 /*$PAGE*/
175 /*
176 *********************************************************************************************************
177 * CREATE A TASK
178 *
179 * Description: This function is used to have uC/OS-II manage the execution of a task. Tasks can either
180 * be created prior to the start of multitasking or by a running task. A task cannot be
181 * created by an ISR.
182 *
183 * Arguments : task is a pointer to the task's code
184 *
185 * p_arg is a pointer to an optional data area which can be used to pass parameters to
186 * the task when the task first executes. Where the task is concerned it thinks
187 * it was invoked and passed the argument 'p_arg' as follows:
188 *
189 * void Task (void *p_arg)
190 * {
191 * for (;;) {
192 * Task code;
193 * }
194 * }
195 *
196 * ptos is a pointer to the task's top of stack. If the configuration constant
197 * OS_STK_GROWTH is set to 1, the stack is assumed to grow downward (i.e. from high
198 * memory to low memory). 'pstk' will thus point to the highest (valid) memory
199 * location of the stack. If OS_STK_GROWTH is set to 0, 'pstk' will point to the
200 * lowest memory location of the stack and the stack will grow with increasing
201 * memory locations.
202 *
203 * prio is the task's priority. A unique priority MUST be assigned to each task and the
204 * lower the number, the higher the priority.
205 *
206 * Returns : OS_ERR_NONE if the function was successful.
207 * OS_PRIO_EXIT if the task priority already exist
208 * (each task MUST have a unique priority).
209 * OS_ERR_PRIO_INVALID if the priority you specify is higher that the maximum allowed
210 * (i.e. >= OS_LOWEST_PRIO)
211 * OS_ERR_TASK_CREATE_ISR if you tried to create a task from an ISR.
212 *********************************************************************************************************
213 */
214 
215 #if OS_TASK_CREATE_EN > 0u
216 INT8U OSTaskCreate (void (*task)(void *p_arg),
217  void *p_arg,
218  OS_STK *ptos,
219  INT8U prio)
220 {
221  OS_STK *psp;
222  INT8U err;
223 #if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
224  OS_CPU_SR cpu_sr = 0u;
225 #endif
226 
227 
228 
229 #if OS_ARG_CHK_EN > 0u
230  if (prio > OS_LOWEST_PRIO) { /* Make sure priority is within allowable range */
231  return (OS_ERR_PRIO_INVALID);
232  }
233 #endif
234  OS_ENTER_CRITICAL();
235  if (OSIntNesting > 0u) { /* Make sure we don't create the task from within an ISR */
236  OS_EXIT_CRITICAL();
237  return (OS_ERR_TASK_CREATE_ISR);
238  }
239  if (OSTCBPrioTbl[prio] == (OS_TCB *)0) { /* Make sure task doesn't already exist at this priority */
240  OSTCBPrioTbl[prio] = OS_TCB_RESERVED;/* Reserve the priority to prevent others from doing ... */
241  /* ... the same thing until task is created. */
242  OS_EXIT_CRITICAL();
243  psp = OSTaskStkInit(task, p_arg, ptos, 0u); /* Initialize the task's stack */
244  err = OS_TCBInit(prio, psp, (OS_STK *)0, 0u, 0u, (void *)0, 0u);
245  if (err == OS_ERR_NONE) {
246  if (OSRunning == OS_TRUE) { /* Find highest priority task if multitasking has started */
247  OS_Sched();
248  }
249  } else {
250  OS_ENTER_CRITICAL();
251  OSTCBPrioTbl[prio] = (OS_TCB *)0;/* Make this priority available to others */
252  OS_EXIT_CRITICAL();
253  }
254  return (err);
255  }
256  OS_EXIT_CRITICAL();
257  return (OS_ERR_PRIO_EXIST);
258 }
259 #endif
260 /*$PAGE*/
261 /*
262 *********************************************************************************************************
263 * CREATE A TASK (Extended Version)
264 *
265 * Description: This function is used to have uC/OS-II manage the execution of a task. Tasks can either
266 * be created prior to the start of multitasking or by a running task. A task cannot be
267 * created by an ISR. This function is similar to OSTaskCreate() except that it allows
268 * additional information about a task to be specified.
269 *
270 * Arguments : task is a pointer to the task's code
271 *
272 * p_arg is a pointer to an optional data area which can be used to pass parameters to
273 * the task when the task first executes. Where the task is concerned it thinks
274 * it was invoked and passed the argument 'p_arg' as follows:
275 *
276 * void Task (void *p_arg)
277 * {
278 * for (;;) {
279 * Task code;
280 * }
281 * }
282 *
283 * ptos is a pointer to the task's top of stack. If the configuration constant
284 * OS_STK_GROWTH is set to 1, the stack is assumed to grow downward (i.e. from high
285 * memory to low memory). 'ptos' will thus point to the highest (valid) memory
286 * location of the stack. If OS_STK_GROWTH is set to 0, 'ptos' will point to the
287 * lowest memory location of the stack and the stack will grow with increasing
288 * memory locations. 'ptos' MUST point to a valid 'free' data item.
289 *
290 * prio is the task's priority. A unique priority MUST be assigned to each task and the
291 * lower the number, the higher the priority.
292 *
293 * id is the task's ID (0..65535)
294 *
295 * pbos is a pointer to the task's bottom of stack. If the configuration constant
296 * OS_STK_GROWTH is set to 1, the stack is assumed to grow downward (i.e. from high
297 * memory to low memory). 'pbos' will thus point to the LOWEST (valid) memory
298 * location of the stack. If OS_STK_GROWTH is set to 0, 'pbos' will point to the
299 * HIGHEST memory location of the stack and the stack will grow with increasing
300 * memory locations. 'pbos' MUST point to a valid 'free' data item.
301 *
302 * stk_size is the size of the stack in number of elements. If OS_STK is set to INT8U,
303 * 'stk_size' corresponds to the number of bytes available. If OS_STK is set to
304 * INT16U, 'stk_size' contains the number of 16-bit entries available. Finally, if
305 * OS_STK is set to INT32U, 'stk_size' contains the number of 32-bit entries
306 * available on the stack.
307 *
308 * pext is a pointer to a user supplied memory location which is used as a TCB extension.
309 * For example, this user memory can hold the contents of floating-point registers
310 * during a context switch, the time each task takes to execute, the number of times
311 * the task has been switched-in, etc.
312 *
313 * opt contains additional information (or options) about the behavior of the task. The
314 * LOWER 8-bits are reserved by uC/OS-II while the upper 8 bits can be application
315 * specific. See OS_TASK_OPT_??? in uCOS-II.H. Current choices are:
316 *
317 * OS_TASK_OPT_STK_CHK Stack checking to be allowed for the task
318 * OS_TASK_OPT_STK_CLR Clear the stack when the task is created
319 * OS_TASK_OPT_SAVE_FP If the CPU has floating-point registers, save them
320 * during a context switch.
321 *
322 * Returns : OS_ERR_NONE if the function was successful.
323 * OS_PRIO_EXIT if the task priority already exist
324 * (each task MUST have a unique priority).
325 * OS_ERR_PRIO_INVALID if the priority you specify is higher that the maximum allowed
326 * (i.e. > OS_LOWEST_PRIO)
327 * OS_ERR_TASK_CREATE_ISR if you tried to create a task from an ISR.
328 *********************************************************************************************************
329 */
330 /*$PAGE*/
331 #if OS_TASK_CREATE_EXT_EN > 0u
332 INT8U OSTaskCreateExt (void (*task)(void *p_arg),
333  void *p_arg,
334  OS_STK *ptos,
335  INT8U prio,
336  INT16U id,
337  OS_STK *pbos,
338  INT32U stk_size,
339  void *pext,
340  INT16U opt)
341 {
342  OS_STK *psp;
343  INT8U err;
344 #if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
345  OS_CPU_SR cpu_sr = 0u;
346 #endif
347 
348 
349 
350 #if OS_ARG_CHK_EN > 0u
351  if (prio > OS_LOWEST_PRIO) { /* Make sure priority is within allowable range */
352  return (OS_ERR_PRIO_INVALID);
353  }
354 #endif
355  OS_ENTER_CRITICAL();
356  if (OSIntNesting > 0u) { /* Make sure we don't create the task from within an ISR */
357  OS_EXIT_CRITICAL();
358  return (OS_ERR_TASK_CREATE_ISR);
359  }
360  if (OSTCBPrioTbl[prio] == (OS_TCB *)0) { /* Make sure task doesn't already exist at this priority */
361  OSTCBPrioTbl[prio] = OS_TCB_RESERVED;/* Reserve the priority to prevent others from doing ... */
362  /* ... the same thing until task is created. */
363  OS_EXIT_CRITICAL();
364 
365 #if (OS_TASK_STAT_STK_CHK_EN > 0u)
366  OS_TaskStkClr(pbos, stk_size, opt); /* Clear the task stack (if needed) */
367 #endif
368 
369  psp = OSTaskStkInit(task, p_arg, ptos, opt); /* Initialize the task's stack */
370  err = OS_TCBInit(prio, psp, pbos, id, stk_size, pext, opt);
371  if (err == OS_ERR_NONE) {
372  if (OSRunning == OS_TRUE) { /* Find HPT if multitasking has started */
373  OS_Sched();
374  }
375  } else {
376  OS_ENTER_CRITICAL();
377  OSTCBPrioTbl[prio] = (OS_TCB *)0; /* Make this priority avail. to others */
378  OS_EXIT_CRITICAL();
379  }
380  return (err);
381  }
382  OS_EXIT_CRITICAL();
383  return (OS_ERR_PRIO_EXIST);
384 }
385 #endif
386 /*$PAGE*/
387 /*
388 *********************************************************************************************************
389 * DELETE A TASK
390 *
391 * Description: This function allows you to delete a task. The calling task can delete itself by
392 * its own priority number. The deleted task is returned to the dormant state and can be
393 * re-activated by creating the deleted task again.
394 *
395 * Arguments : prio is the priority of the task to delete. Note that you can explicitely delete
396 * the current task without knowing its priority level by setting 'prio' to
397 * OS_PRIO_SELF.
398 *
399 * Returns : OS_ERR_NONE if the call is successful
400 * OS_ERR_TASK_DEL_IDLE if you attempted to delete uC/OS-II's idle task
401 * OS_ERR_PRIO_INVALID if the priority you specify is higher that the maximum allowed
402 * (i.e. >= OS_LOWEST_PRIO) or, you have not specified OS_PRIO_SELF.
403 * OS_ERR_TASK_DEL if the task is assigned to a Mutex PIP.
404 * OS_ERR_TASK_NOT_EXIST if the task you want to delete does not exist.
405 * OS_ERR_TASK_DEL_ISR if you tried to delete a task from an ISR
406 *
407 * Notes : 1) To reduce interrupt latency, OSTaskDel() 'disables' the task:
408 * a) by making it not ready
409 * b) by removing it from any wait lists
410 * c) by preventing OSTimeTick() from making the task ready to run.
411 * The task can then be 'unlinked' from the miscellaneous structures in uC/OS-II.
412 * 2) The function OS_Dummy() is called after OS_EXIT_CRITICAL() because, on most processors,
413 * the next instruction following the enable interrupt instruction is ignored.
414 * 3) An ISR cannot delete a task.
415 * 4) The lock nesting counter is incremented because, for a brief instant, if the current
416 * task is being deleted, the current task would not be able to be rescheduled because it
417 * is removed from the ready list. Incrementing the nesting counter prevents another task
418 * from being schedule. This means that an ISR would return to the current task which is
419 * being deleted. The rest of the deletion would thus be able to be completed.
420 *********************************************************************************************************
421 */
422 
423 #if OS_TASK_DEL_EN > 0u
424 INT8U OSTaskDel (INT8U prio)
425 {
426 #if (OS_FLAG_EN > 0u) && (OS_MAX_FLAGS > 0u)
427  OS_FLAG_NODE *pnode;
428 #endif
429  OS_TCB *ptcb;
430 #if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
431  OS_CPU_SR cpu_sr = 0u;
432 #endif
433 
434 
435 
436  if (OSIntNesting > 0u) { /* See if trying to delete from ISR */
437  return (OS_ERR_TASK_DEL_ISR);
438  }
439  if (prio == OS_TASK_IDLE_PRIO) { /* Not allowed to delete idle task */
440  return (OS_ERR_TASK_DEL_IDLE);
441  }
442 #if OS_ARG_CHK_EN > 0u
443  if (prio >= OS_LOWEST_PRIO) { /* Task priority valid ? */
444  if (prio != OS_PRIO_SELF) {
445  return (OS_ERR_PRIO_INVALID);
446  }
447  }
448 #endif
449 
450 /*$PAGE*/
451  OS_ENTER_CRITICAL();
452  if (prio == OS_PRIO_SELF) { /* See if requesting to delete self */
453  prio = OSTCBCur->OSTCBPrio; /* Set priority to delete to current */
454  }
455  ptcb = OSTCBPrioTbl[prio];
456  if (ptcb == (OS_TCB *)0) { /* Task to delete must exist */
457  OS_EXIT_CRITICAL();
458  return (OS_ERR_TASK_NOT_EXIST);
459  }
460  if (ptcb == OS_TCB_RESERVED) { /* Must not be assigned to Mutex */
461  OS_EXIT_CRITICAL();
462  return (OS_ERR_TASK_DEL);
463  }
464 
465  OSRdyTbl[ptcb->OSTCBY] &= ~ptcb->OSTCBBitX;
466  if (OSRdyTbl[ptcb->OSTCBY] == 0u) { /* Make task not ready */
467  OSRdyGrp &= ~ptcb->OSTCBBitY;
468  }
469 
470 #if (OS_EVENT_EN)
471  if (ptcb->OSTCBEventPtr != (OS_EVENT *)0) {
472  OS_EventTaskRemove(ptcb, ptcb->OSTCBEventPtr); /* Remove this task from any event wait list */
473  }
474 #if (OS_EVENT_MULTI_EN > 0u)
475  if (ptcb->OSTCBEventMultiPtr != (OS_EVENT **)0) { /* Remove this task from any events' wait lists*/
476  OS_EventTaskRemoveMulti(ptcb, ptcb->OSTCBEventMultiPtr);
477  }
478 #endif
479 #endif
480 
481 #if (OS_FLAG_EN > 0u) && (OS_MAX_FLAGS > 0u)
482  pnode = ptcb->OSTCBFlagNode;
483  if (pnode != (OS_FLAG_NODE *)0) { /* If task is waiting on event flag */
484  OS_FlagUnlink(pnode); /* Remove from wait list */
485  }
486 #endif
487 
488  ptcb->OSTCBDly = 0u; /* Prevent OSTimeTick() from updating */
489  ptcb->OSTCBStat = OS_STAT_RDY; /* Prevent task from being resumed */
490  ptcb->OSTCBStatPend = OS_STAT_PEND_OK;
491  if (OSLockNesting < 255u) { /* Make sure we don't context switch */
492  OSLockNesting++;
493  }
494  OS_EXIT_CRITICAL(); /* Enabling INT. ignores next instruc. */
495  OS_Dummy(); /* ... Dummy ensures that INTs will be */
496  OS_ENTER_CRITICAL(); /* ... disabled HERE! */
497  if (OSLockNesting > 0u) { /* Remove context switch lock */
498  OSLockNesting--;
499  }
500  OSTaskDelHook(ptcb); /* Call user defined hook */
501  OSTaskCtr--; /* One less task being managed */
502  OSTCBPrioTbl[prio] = (OS_TCB *)0; /* Clear old priority entry */
503  if (ptcb->OSTCBPrev == (OS_TCB *)0) { /* Remove from TCB chain */
504  ptcb->OSTCBNext->OSTCBPrev = (OS_TCB *)0;
505  OSTCBList = ptcb->OSTCBNext;
506  } else {
507  ptcb->OSTCBPrev->OSTCBNext = ptcb->OSTCBNext;
508  ptcb->OSTCBNext->OSTCBPrev = ptcb->OSTCBPrev;
509  }
510  ptcb->OSTCBNext = OSTCBFreeList; /* Return TCB to free TCB list */
511  OSTCBFreeList = ptcb;
512 #if OS_TASK_NAME_EN > 0u
513  ptcb->OSTCBTaskName = (INT8U *)"?";
514 #endif
515  OS_EXIT_CRITICAL();
516  if (OSRunning == OS_TRUE) {
517  OS_Sched(); /* Find new highest priority task */
518  }
519  return (OS_ERR_NONE);
520 }
521 #endif
522 /*$PAGE*/
523 /*
524 *********************************************************************************************************
525 * REQUEST THAT A TASK DELETE ITSELF
526 *
527 * Description: This function is used to:
528 * a) notify a task to delete itself.
529 * b) to see if a task requested that the current task delete itself.
530 * This function is a little tricky to understand. Basically, you have a task that needs
531 * to be deleted however, this task has resources that it has allocated (memory buffers,
532 * semaphores, mailboxes, queues etc.). The task cannot be deleted otherwise these
533 * resources would not be freed. The requesting task calls OSTaskDelReq() to indicate that
534 * the task needs to be deleted. Deleting of the task is however, deferred to the task to
535 * be deleted. For example, suppose that task #10 needs to be deleted. The requesting task
536 * example, task #5, would call OSTaskDelReq(10). When task #10 gets to execute, it calls
537 * this function by specifying OS_PRIO_SELF and monitors the returned value. If the return
538 * value is OS_ERR_TASK_DEL_REQ, another task requested a task delete. Task #10 would look like
539 * this:
540 *
541 * void Task(void *p_arg)
542 * {
543 * .
544 * .
545 * while (1) {
546 * OSTimeDly(1);
547 * if (OSTaskDelReq(OS_PRIO_SELF) == OS_ERR_TASK_DEL_REQ) {
548 * Release any owned resources;
549 * De-allocate any dynamic memory;
550 * OSTaskDel(OS_PRIO_SELF);
551 * }
552 * }
553 * }
554 *
555 * Arguments : prio is the priority of the task to request the delete from
556 *
557 * Returns : OS_ERR_NONE if the task exist and the request has been registered
558 * OS_ERR_TASK_NOT_EXIST if the task has been deleted. This allows the caller to know whether
559 * the request has been executed.
560 * OS_ERR_TASK_DEL if the task is assigned to a Mutex.
561 * OS_ERR_TASK_DEL_IDLE if you requested to delete uC/OS-II's idle task
562 * OS_ERR_PRIO_INVALID if the priority you specify is higher that the maximum allowed
563 * (i.e. >= OS_LOWEST_PRIO) or, you have not specified OS_PRIO_SELF.
564 * OS_ERR_TASK_DEL_REQ if a task (possibly another task) requested that the running task be
565 * deleted.
566 *********************************************************************************************************
567 */
568 /*$PAGE*/
569 #if OS_TASK_DEL_EN > 0u
570 INT8U OSTaskDelReq (INT8U prio)
571 {
572  INT8U stat;
573  OS_TCB *ptcb;
574 #if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
575  OS_CPU_SR cpu_sr = 0u;
576 #endif
577 
578 
579 
580  if (prio == OS_TASK_IDLE_PRIO) { /* Not allowed to delete idle task */
581  return (OS_ERR_TASK_DEL_IDLE);
582  }
583 #if OS_ARG_CHK_EN > 0u
584  if (prio >= OS_LOWEST_PRIO) { /* Task priority valid ? */
585  if (prio != OS_PRIO_SELF) {
586  return (OS_ERR_PRIO_INVALID);
587  }
588  }
589 #endif
590  if (prio == OS_PRIO_SELF) { /* See if a task is requesting to ... */
591  OS_ENTER_CRITICAL(); /* ... this task to delete itself */
592  stat = OSTCBCur->OSTCBDelReq; /* Return request status to caller */
593  OS_EXIT_CRITICAL();
594  return (stat);
595  }
596  OS_ENTER_CRITICAL();
597  ptcb = OSTCBPrioTbl[prio];
598  if (ptcb == (OS_TCB *)0) { /* Task to delete must exist */
599  OS_EXIT_CRITICAL();
600  return (OS_ERR_TASK_NOT_EXIST); /* Task must already be deleted */
601  }
602  if (ptcb == OS_TCB_RESERVED) { /* Must NOT be assigned to a Mutex */
603  OS_EXIT_CRITICAL();
604  return (OS_ERR_TASK_DEL);
605  }
606  ptcb->OSTCBDelReq = OS_ERR_TASK_DEL_REQ; /* Set flag indicating task to be DEL. */
607  OS_EXIT_CRITICAL();
608  return (OS_ERR_NONE);
609 }
610 #endif
611 /*$PAGE*/
612 /*
613 *********************************************************************************************************
614 * GET THE NAME OF A TASK
615 *
616 * Description: This function is called to obtain the name of a task.
617 *
618 * Arguments : prio is the priority of the task that you want to obtain the name from.
619 *
620 * pname is a pointer to a pointer to an ASCII string that will receive the name of the task.
621 *
622 * perr is a pointer to an error code that can contain one of the following values:
623 *
624 * OS_ERR_NONE if the requested task is resumed
625 * OS_ERR_TASK_NOT_EXIST if the task has not been created or is assigned to a Mutex
626 * OS_ERR_PRIO_INVALID if you specified an invalid priority:
627 * A higher value than the idle task or not OS_PRIO_SELF.
628 * OS_ERR_PNAME_NULL You passed a NULL pointer for 'pname'
629 * OS_ERR_NAME_GET_ISR You called this function from an ISR
630 *
631 *
632 * Returns : The length of the string or 0 if the task does not exist.
633 *********************************************************************************************************
634 */
635 
636 #if OS_TASK_NAME_EN > 0u
637 INT8U OSTaskNameGet (INT8U prio,
638  INT8U **pname,
639  INT8U *perr)
640 {
641  OS_TCB *ptcb;
642  INT8U len;
643 #if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
644  OS_CPU_SR cpu_sr = 0u;
645 #endif
646 
647 
648 
649 #if OS_ARG_CHK_EN > 0u
650  if (perr == (INT8U *)0) { /* Validate 'perr' */
651  return (0u);
652  }
653  if (prio > OS_LOWEST_PRIO) { /* Task priority valid ? */
654  if (prio != OS_PRIO_SELF) {
655  *perr = OS_ERR_PRIO_INVALID; /* No */
656  return (0u);
657  }
658  }
659  if (pname == (INT8U **)0) { /* Is 'pname' a NULL pointer? */
660  *perr = OS_ERR_PNAME_NULL; /* Yes */
661  return (0u);
662  }
663 #endif
664  if (OSIntNesting > 0u) { /* See if trying to call from an ISR */
665  *perr = OS_ERR_NAME_GET_ISR;
666  return (0u);
667  }
668  OS_ENTER_CRITICAL();
669  if (prio == OS_PRIO_SELF) { /* See if caller desires it's own name */
670  prio = OSTCBCur->OSTCBPrio;
671  }
672  ptcb = OSTCBPrioTbl[prio];
673  if (ptcb == (OS_TCB *)0) { /* Does task exist? */
674  OS_EXIT_CRITICAL(); /* No */
675  *perr = OS_ERR_TASK_NOT_EXIST;
676  return (0u);
677  }
678  if (ptcb == OS_TCB_RESERVED) { /* Task assigned to a Mutex? */
679  OS_EXIT_CRITICAL(); /* Yes */
680  *perr = OS_ERR_TASK_NOT_EXIST;
681  return (0u);
682  }
683  *pname = ptcb->OSTCBTaskName;
684  len = OS_StrLen(*pname);
685  OS_EXIT_CRITICAL();
686  *perr = OS_ERR_NONE;
687  return (len);
688 }
689 #endif
690 
691 /*$PAGE*/
692 /*
693 *********************************************************************************************************
694 * ASSIGN A NAME TO A TASK
695 *
696 * Description: This function is used to set the name of a task.
697 *
698 * Arguments : prio is the priority of the task that you want the assign a name to.
699 *
700 * pname is a pointer to an ASCII string that contains the name of the task.
701 *
702 * perr is a pointer to an error code that can contain one of the following values:
703 *
704 * OS_ERR_NONE if the requested task is resumed
705 * OS_ERR_TASK_NOT_EXIST if the task has not been created or is assigned to a Mutex
706 * OS_ERR_PNAME_NULL You passed a NULL pointer for 'pname'
707 * OS_ERR_PRIO_INVALID if you specified an invalid priority:
708 * A higher value than the idle task or not OS_PRIO_SELF.
709 * OS_ERR_NAME_SET_ISR if you called this function from an ISR
710 *
711 * Returns : None
712 *********************************************************************************************************
713 */
714 #if OS_TASK_NAME_EN > 0u
715 void OSTaskNameSet (INT8U prio,
716  INT8U *pname,
717  INT8U *perr)
718 {
719  OS_TCB *ptcb;
720 #if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
721  OS_CPU_SR cpu_sr = 0u;
722 #endif
723 
724 
725 
726 #if OS_ARG_CHK_EN > 0u
727  if (perr == (INT8U *)0) { /* Validate 'perr' */
728  return;
729  }
730  if (prio > OS_LOWEST_PRIO) { /* Task priority valid ? */
731  if (prio != OS_PRIO_SELF) {
732  *perr = OS_ERR_PRIO_INVALID; /* No */
733  return;
734  }
735  }
736  if (pname == (INT8U *)0) { /* Is 'pname' a NULL pointer? */
737  *perr = OS_ERR_PNAME_NULL; /* Yes */
738  return;
739  }
740 #endif
741  if (OSIntNesting > 0u) { /* See if trying to call from an ISR */
742  *perr = OS_ERR_NAME_SET_ISR;
743  return;
744  }
745  OS_ENTER_CRITICAL();
746  if (prio == OS_PRIO_SELF) { /* See if caller desires to set it's own name */
747  prio = OSTCBCur->OSTCBPrio;
748  }
749  ptcb = OSTCBPrioTbl[prio];
750  if (ptcb == (OS_TCB *)0) { /* Does task exist? */
751  OS_EXIT_CRITICAL(); /* No */
752  *perr = OS_ERR_TASK_NOT_EXIST;
753  return;
754  }
755  if (ptcb == OS_TCB_RESERVED) { /* Task assigned to a Mutex? */
756  OS_EXIT_CRITICAL(); /* Yes */
757  *perr = OS_ERR_TASK_NOT_EXIST;
758  return;
759  }
760  ptcb->OSTCBTaskName = pname;
761  OS_EXIT_CRITICAL();
762  *perr = OS_ERR_NONE;
763 }
764 #endif
765 
766 /*$PAGE*/
767 /*
768 *********************************************************************************************************
769 * RESUME A SUSPENDED TASK
770 *
771 * Description: This function is called to resume a previously suspended task. This is the only call that
772 * will remove an explicit task suspension.
773 *
774 * Arguments : prio is the priority of the task to resume.
775 *
776 * Returns : OS_ERR_NONE if the requested task is resumed
777 * OS_ERR_PRIO_INVALID if the priority you specify is higher that the maximum allowed
778 * (i.e. >= OS_LOWEST_PRIO)
779 * OS_ERR_TASK_RESUME_PRIO if the task to resume does not exist
780 * OS_ERR_TASK_NOT_EXIST if the task is assigned to a Mutex PIP
781 * OS_ERR_TASK_NOT_SUSPENDED if the task to resume has not been suspended
782 *********************************************************************************************************
783 */
784 
785 #if OS_TASK_SUSPEND_EN > 0u
786 INT8U OSTaskResume (INT8U prio)
787 {
788  OS_TCB *ptcb;
789 #if OS_CRITICAL_METHOD == 3u /* Storage for CPU status register */
790  OS_CPU_SR cpu_sr = 0u;
791 #endif
792 
793 
794 
795 #if OS_ARG_CHK_EN > 0u
796  if (prio >= OS_LOWEST_PRIO) { /* Make sure task priority is valid */
797  return (OS_ERR_PRIO_INVALID);
798  }
799 #endif
800  OS_ENTER_CRITICAL();
801  ptcb = OSTCBPrioTbl[prio];
802  if (ptcb == (OS_TCB *)0) { /* Task to suspend must exist */
803  OS_EXIT_CRITICAL();
804  return (OS_ERR_TASK_RESUME_PRIO);
805  }
806  if (ptcb == OS_TCB_RESERVED) { /* See if assigned to Mutex */
807  OS_EXIT_CRITICAL();
808  return (OS_ERR_TASK_NOT_EXIST);
809  }
810  if ((ptcb->OSTCBStat & OS_STAT_SUSPEND) != OS_STAT_RDY) { /* Task must be suspended */
811  ptcb->OSTCBStat &= ~(INT8U)OS_STAT_SUSPEND; /* Remove suspension */
812  if (ptcb->OSTCBStat == OS_STAT_RDY) { /* See if task is now ready */
813  if (ptcb->OSTCBDly == 0u) {
814  OSRdyGrp |= ptcb->OSTCBBitY; /* Yes, Make task ready to run */
815  OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
816  OS_EXIT_CRITICAL();
817  if (OSRunning == OS_TRUE) {
818  OS_Sched(); /* Find new highest priority task */
819  }
820  } else {
821  OS_EXIT_CRITICAL();
822  }
823  } else { /* Must be pending on event */
824  OS_EXIT_CRITICAL();
825  }
826  return (OS_ERR_NONE);
827  }
828  OS_EXIT_CRITICAL();
829  return (OS_ERR_TASK_NOT_SUSPENDED);
830 }
831 #endif
832 /*$PAGE*/
833 /*
834 *********************************************************************************************************
835 * STACK CHECKING
836 *
837 * Description: This function is called to check the amount of free memory left on the specified task's
838 * stack.
839 *
840 * Arguments : prio is the task priority
841 *
842 * p_stk_data is a pointer to a data structure of type OS_STK_DATA.
843 *
844 * Returns : OS_ERR_NONE upon success
845 * OS_ERR_PRIO_INVALID if the priority you specify is higher that the maximum allowed
846 * (i.e. > OS_LOWEST_PRIO) or, you have not specified OS_PRIO_SELF.
847 * OS_ERR_TASK_NOT_EXIST if the desired task has not been created or is assigned to a Mutex PIP
848 * OS_ERR_TASK_OPT if you did NOT specified OS_TASK_OPT_STK_CHK when the task was created
849 * OS_ERR_PDATA_NULL if 'p_stk_data' is a NULL pointer
850 *********************************************************************************************************
851 */
852 #if (OS_TASK_STAT_STK_CHK_EN > 0u) && (OS_TASK_CREATE_EXT_EN > 0u)
853 INT8U OSTaskStkChk (INT8U prio,
854  OS_STK_DATA *p_stk_data)
855 {
856  OS_TCB *ptcb;
857  OS_STK *pchk;
858  INT32U nfree;
859  INT32U size;
860 #if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
861  OS_CPU_SR cpu_sr = 0u;
862 #endif
863 
864 
865 
866 #if OS_ARG_CHK_EN > 0u
867  if (prio > OS_LOWEST_PRIO) { /* Make sure task priority is valid */
868  if (prio != OS_PRIO_SELF) {
869  return (OS_ERR_PRIO_INVALID);
870  }
871  }
872  if (p_stk_data == (OS_STK_DATA *)0) { /* Validate 'p_stk_data' */
873  return (OS_ERR_PDATA_NULL);
874  }
875 #endif
876  p_stk_data->OSFree = 0u; /* Assume failure, set to 0 size */
877  p_stk_data->OSUsed = 0u;
878  OS_ENTER_CRITICAL();
879  if (prio == OS_PRIO_SELF) { /* See if check for SELF */
880  prio = OSTCBCur->OSTCBPrio;
881  }
882  ptcb = OSTCBPrioTbl[prio];
883  if (ptcb == (OS_TCB *)0) { /* Make sure task exist */
884  OS_EXIT_CRITICAL();
885  return (OS_ERR_TASK_NOT_EXIST);
886  }
887  if (ptcb == OS_TCB_RESERVED) {
888  OS_EXIT_CRITICAL();
889  return (OS_ERR_TASK_NOT_EXIST);
890  }
891  if ((ptcb->OSTCBOpt & OS_TASK_OPT_STK_CHK) == 0u) { /* Make sure stack checking option is set */
892  OS_EXIT_CRITICAL();
893  return (OS_ERR_TASK_OPT);
894  }
895  nfree = 0u;
896  size = ptcb->OSTCBStkSize;
897  pchk = ptcb->OSTCBStkBottom;
898  OS_EXIT_CRITICAL();
899 #if OS_STK_GROWTH == 1u
900  while (*pchk++ == (OS_STK)0) { /* Compute the number of zero entries on the stk */
901  nfree++;
902  }
903 #else
904  while (*pchk-- == (OS_STK)0) {
905  nfree++;
906  }
907 #endif
908  p_stk_data->OSFree = nfree * sizeof(OS_STK); /* Compute number of free bytes on the stack */
909  p_stk_data->OSUsed = (size - nfree) * sizeof(OS_STK); /* Compute number of bytes used on the stack */
910  return (OS_ERR_NONE);
911 }
912 #endif
913 /*$PAGE*/
914 /*
915 *********************************************************************************************************
916 * SUSPEND A TASK
917 *
918 * Description: This function is called to suspend a task. The task can be the calling task if the
919 * priority passed to OSTaskSuspend() is the priority of the calling task or OS_PRIO_SELF.
920 *
921 * Arguments : prio is the priority of the task to suspend. If you specify OS_PRIO_SELF, the
922 * calling task will suspend itself and rescheduling will occur.
923 *
924 * Returns : OS_ERR_NONE if the requested task is suspended
925 * OS_ERR_TASK_SUSPEND_IDLE if you attempted to suspend the idle task which is not allowed.
926 * OS_ERR_PRIO_INVALID if the priority you specify is higher that the maximum allowed
927 * (i.e. >= OS_LOWEST_PRIO) or, you have not specified OS_PRIO_SELF.
928 * OS_ERR_TASK_SUSPEND_PRIO if the task to suspend does not exist
929 * OS_ERR_TASK_NOT_EXITS if the task is assigned to a Mutex PIP
930 *
931 * Note : You should use this function with great care. If you suspend a task that is waiting for
932 * an event (i.e. a message, a semaphore, a queue ...) you will prevent this task from
933 * running when the event arrives.
934 *********************************************************************************************************
935 */
936 
937 #if OS_TASK_SUSPEND_EN > 0u
938 INT8U OSTaskSuspend (INT8U prio)
939 {
940  BOOLEAN self;
941  OS_TCB *ptcb;
942  INT8U y;
943 #if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
944  OS_CPU_SR cpu_sr = 0u;
945 #endif
946 
947 
948 
949 #if OS_ARG_CHK_EN > 0u
950  if (prio == OS_TASK_IDLE_PRIO) { /* Not allowed to suspend idle task */
951  return (OS_ERR_TASK_SUSPEND_IDLE);
952  }
953  if (prio >= OS_LOWEST_PRIO) { /* Task priority valid ? */
954  if (prio != OS_PRIO_SELF) {
955  return (OS_ERR_PRIO_INVALID);
956  }
957  }
958 #endif
959  OS_ENTER_CRITICAL();
960  if (prio == OS_PRIO_SELF) { /* See if suspend SELF */
961  prio = OSTCBCur->OSTCBPrio;
962  self = OS_TRUE;
963  } else if (prio == OSTCBCur->OSTCBPrio) { /* See if suspending self */
964  self = OS_TRUE;
965  } else {
966  self = OS_FALSE; /* No suspending another task */
967  }
968  ptcb = OSTCBPrioTbl[prio];
969  if (ptcb == (OS_TCB *)0) { /* Task to suspend must exist */
970  OS_EXIT_CRITICAL();
971  return (OS_ERR_TASK_SUSPEND_PRIO);
972  }
973  if (ptcb == OS_TCB_RESERVED) { /* See if assigned to Mutex */
974  OS_EXIT_CRITICAL();
975  return (OS_ERR_TASK_NOT_EXIST);
976  }
977  y = ptcb->OSTCBY;
978  OSRdyTbl[y] &= ~ptcb->OSTCBBitX; /* Make task not ready */
979  if (OSRdyTbl[y] == 0u) {
980  OSRdyGrp &= ~ptcb->OSTCBBitY;
981  }
982  ptcb->OSTCBStat |= OS_STAT_SUSPEND; /* Status of task is 'SUSPENDED' */
983  OS_EXIT_CRITICAL();
984  if (self == OS_TRUE) { /* Context switch only if SELF */
985  OS_Sched(); /* Find new highest priority task */
986  }
987  return (OS_ERR_NONE);
988 }
989 #endif
990 /*$PAGE*/
991 /*
992 *********************************************************************************************************
993 * QUERY A TASK
994 *
995 * Description: This function is called to obtain a copy of the desired task's TCB.
996 *
997 * Arguments : prio is the priority of the task to obtain information from.
998 *
999 * p_task_data is a pointer to where the desired task's OS_TCB will be stored.
1000 *
1001 * Returns : OS_ERR_NONE if the requested task is suspended
1002 * OS_ERR_PRIO_INVALID if the priority you specify is higher that the maximum allowed
1003 * (i.e. > OS_LOWEST_PRIO) or, you have not specified OS_PRIO_SELF.
1004 * OS_ERR_PRIO if the desired task has not been created
1005 * OS_ERR_TASK_NOT_EXIST if the task is assigned to a Mutex PIP
1006 * OS_ERR_PDATA_NULL if 'p_task_data' is a NULL pointer
1007 *********************************************************************************************************
1008 */
1009 
1010 #if OS_TASK_QUERY_EN > 0u
1011 INT8U OSTaskQuery (INT8U prio,
1012  OS_TCB *p_task_data)
1013 {
1014  OS_TCB *ptcb;
1015 #if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
1016  OS_CPU_SR cpu_sr = 0u;
1017 #endif
1018 
1019 
1020 
1021 #if OS_ARG_CHK_EN > 0u
1022  if (prio > OS_LOWEST_PRIO) { /* Task priority valid ? */
1023  if (prio != OS_PRIO_SELF) {
1024  return (OS_ERR_PRIO_INVALID);
1025  }
1026  }
1027  if (p_task_data == (OS_TCB *)0) { /* Validate 'p_task_data' */
1028  return (OS_ERR_PDATA_NULL);
1029  }
1030 #endif
1031  OS_ENTER_CRITICAL();
1032  if (prio == OS_PRIO_SELF) { /* See if suspend SELF */
1033  prio = OSTCBCur->OSTCBPrio;
1034  }
1035  ptcb = OSTCBPrioTbl[prio];
1036  if (ptcb == (OS_TCB *)0) { /* Task to query must exist */
1037  OS_EXIT_CRITICAL();
1038  return (OS_ERR_PRIO);
1039  }
1040  if (ptcb == OS_TCB_RESERVED) { /* Task to query must not be assigned to a Mutex */
1041  OS_EXIT_CRITICAL();
1042  return (OS_ERR_TASK_NOT_EXIST);
1043  }
1044  /* Copy TCB into user storage area */
1045  OS_MemCopy((INT8U *)p_task_data, (INT8U *)ptcb, sizeof(OS_TCB));
1046  OS_EXIT_CRITICAL();
1047  return (OS_ERR_NONE);
1048 }
1049 #endif
1050 /*$PAGE*/
1051 /*
1052 *********************************************************************************************************
1053 * GET THE CURRENT VALUE OF A TASK REGISTER
1054 *
1055 * Description: This function is called to obtain the current value of a task register. Task registers
1056 * are application specific and can be used to store task specific values such as 'error
1057 * numbers' (i.e. errno), statistics, etc. Each task register can hold a 32-bit value.
1058 *
1059 * Arguments : prio is the priority of the task you want to get the task register from. If you
1060 * specify OS_PRIO_SELF then the task register of the current task will be obtained.
1061 *
1062 * id is the 'id' of the desired task register. Note that the 'id' must be less
1063 * than OS_TASK_REG_TBL_SIZE
1064 *
1065 * perr is a pointer to a variable that will hold an error code related to this call.
1066 *
1067 * OS_ERR_NONE if the call was successful
1068 * OS_ERR_PRIO_INVALID if you specified an invalid priority
1069 * OS_ERR_ID_INVALID if the 'id' is not between 0 and OS_TASK_REG_TBL_SIZE-1
1070 *
1071 * Returns : The current value of the task's register or 0 if an error is detected.
1072 *
1073 * Note(s) : The maximum number of task variables is 254
1074 *********************************************************************************************************
1075 */
1076 
1077 #if OS_TASK_REG_TBL_SIZE > 0u
1078 INT32U OSTaskRegGet (INT8U prio,
1079  INT8U id,
1080  INT8U *perr)
1081 {
1082 #if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
1083  OS_CPU_SR cpu_sr = 0u;
1084 #endif
1085  INT32U value;
1086  OS_TCB *ptcb;
1087 
1088 
1089 #if OS_ARG_CHK_EN > 0u
1090  if (prio >= OS_LOWEST_PRIO) {
1091  if (prio != OS_PRIO_SELF) {
1092  *perr = OS_ERR_PRIO_INVALID;
1093  return (0u);
1094  }
1095  }
1096  if (id >= OS_TASK_REG_TBL_SIZE) {
1097  *perr = OS_ERR_ID_INVALID;
1098  return (0u);
1099  }
1100 #endif
1101  OS_ENTER_CRITICAL();
1102  if (prio == OS_PRIO_SELF) { /* See if need to get register from current task */
1103  ptcb = OSTCBCur;
1104  } else {
1105  ptcb = OSTCBPrioTbl[prio];
1106  }
1107  value = ptcb->OSTCBRegTbl[id];
1108  OS_EXIT_CRITICAL();
1109  *perr = OS_ERR_NONE;
1110  return (value);
1111 }
1112 #endif
1113 
1114 /*$PAGE*/
1115 /*
1116 *********************************************************************************************************
1117 * SET THE CURRENT VALUE OF A TASK VARIABLE
1118 *
1119 * Description: This function is called to change the current value of a task register. Task registers
1120 * are application specific and can be used to store task specific values such as 'error
1121 * numbers' (i.e. errno), statistics, etc. Each task register can hold a 32-bit value.
1122 *
1123 * Arguments : prio is the priority of the task you want to set the task register for. If you
1124 * specify OS_PRIO_SELF then the task register of the current task will be obtained.
1125 *
1126 * var_id is the 'id' of the desired task register. Note that the 'id' must be less
1127 * than OS_TASK_REG_TBL_SIZE
1128 *
1129 * value is the desired value for the task register.
1130 *
1131 * perr is a pointer to a variable that will hold an error code related to this call.
1132 *
1133 * OS_ERR_NONE if the call was successful
1134 * OS_ERR_PRIO_INVALID if you specified an invalid priority
1135 * OS_ERR_ID_INVALID if the 'id' is not between 0 and OS_TASK_REG_TBL_SIZE-1
1136 *
1137 * Returns : The current value of the task's variable or 0 if an error is detected.
1138 *
1139 * Note(s) : The maximum number of task variables is 254
1140 *********************************************************************************************************
1141 */
1142 
1143 #if OS_TASK_REG_TBL_SIZE > 0u
1144 void OSTaskRegSet (INT8U prio,
1145  INT8U id,
1146  INT32U value,
1147  INT8U *perr)
1148 {
1149 #if OS_CRITICAL_METHOD == 3u /* Allocate storage for CPU status register */
1150  OS_CPU_SR cpu_sr = 0u;
1151 #endif
1152  OS_TCB *ptcb;
1153 
1154 
1155 #if OS_ARG_CHK_EN > 0u
1156  if (prio >= OS_LOWEST_PRIO) {
1157  if (prio != OS_PRIO_SELF) {
1158  *perr = OS_ERR_PRIO_INVALID;
1159  return;
1160  }
1161  }
1162  if (id >= OS_TASK_REG_TBL_SIZE) {
1163  *perr = OS_ERR_ID_INVALID;
1164  return;
1165  }
1166 #endif
1167  OS_ENTER_CRITICAL();
1168  if (prio == OS_PRIO_SELF) { /* See if need to get register from current task */
1169  ptcb = OSTCBCur;
1170  } else {
1171  ptcb = OSTCBPrioTbl[prio];
1172  }
1173  ptcb->OSTCBRegTbl[id] = value;
1174  OS_EXIT_CRITICAL();
1175  *perr = OS_ERR_NONE;
1176 }
1177 #endif
1178 
1179 /*$PAGE*/
1180 /*
1181 *********************************************************************************************************
1182 * CATCH ACCIDENTAL TASK RETURN
1183 *
1184 * Description: This function is called if a task accidentally returns without deleting itself. In other
1185 * words, a task should either be an infinite loop or delete itself if it's done.
1186 *
1187 * Arguments : none
1188 *
1189 * Returns : none
1190 *
1191 * Note(s) : This function is INTERNAL to uC/OS-II and your application should not call it.
1192 *********************************************************************************************************
1193 */
1194 
1195 void OS_TaskReturn (void)
1196 {
1197  OSTaskReturnHook(OSTCBCur); /* Call hook to let user decide on what to do */
1198 
1199 #if OS_TASK_DEL_EN > 0u
1200  (void)OSTaskDel(OS_PRIO_SELF); /* Delete task if it accidentally returns! */
1201 #else
1202  for (;;) {
1203  OSTimeDly(OS_TICKS_PER_SEC);
1204  }
1205 #endif
1206 }
1207 
1208 /*$PAGE*/
1209 /*
1210 *********************************************************************************************************
1211 * CLEAR TASK STACK
1212 *
1213 * Description: This function is used to clear the stack of a task (i.e. write all zeros)
1214 *
1215 * Arguments : pbos is a pointer to the task's bottom of stack. If the configuration constant
1216 * OS_STK_GROWTH is set to 1, the stack is assumed to grow downward (i.e. from high
1217 * memory to low memory). 'pbos' will thus point to the lowest (valid) memory
1218 * location of the stack. If OS_STK_GROWTH is set to 0, 'pbos' will point to the
1219 * highest memory location of the stack and the stack will grow with increasing
1220 * memory locations. 'pbos' MUST point to a valid 'free' data item.
1221 *
1222 * size is the number of 'stack elements' to clear.
1223 *
1224 * opt contains additional information (or options) about the behavior of the task. The
1225 * LOWER 8-bits are reserved by uC/OS-II while the upper 8 bits can be application
1226 * specific. See OS_TASK_OPT_??? in uCOS-II.H.
1227 *
1228 * Returns : none
1229 *********************************************************************************************************
1230 */
1231 #if (OS_TASK_STAT_STK_CHK_EN > 0u) && (OS_TASK_CREATE_EXT_EN > 0u)
1232 void OS_TaskStkClr (OS_STK *pbos,
1233  INT32U size,
1234  INT16U opt)
1235 {
1236  if ((opt & OS_TASK_OPT_STK_CHK) != 0x0000u) { /* See if stack checking has been enabled */
1237  if ((opt & OS_TASK_OPT_STK_CLR) != 0x0000u) { /* See if stack needs to be cleared */
1238 #if OS_STK_GROWTH == 1u
1239  while (size > 0u) { /* Stack grows from HIGH to LOW memory */
1240  size--;
1241  *pbos++ = (OS_STK)0; /* Clear from bottom of stack and up! */
1242  }
1243 #else
1244  while (size > 0u) { /* Stack grows from LOW to HIGH memory */
1245  size--;
1246  *pbos-- = (OS_STK)0; /* Clear from bottom of stack and down */
1247  }
1248 #endif
1249  }
1250  }
1251 }
1252 
1253 #endif