ucosII信号量学习资料及代码 -

标题: ucosII信号量学习资料及代码 [打印本页]

作者: urgreat 时间: 2020-6-8 21:45
标题: ucosII信号量学习资料及代码
附件中有某高校ucosII有关信号量的ppt及相关代码。

在uCOS_II.H中增加变量定义 1
在test.c中注释掉变量y 1
文件OS_SEM.C中的OSSemPend函数中添加红色部分代码 1
文件OS_SEM.C中的OSSemPost函数中添加红色部分代码 3

在uCOS_II.H中增加变量定义
/********************************************************************************************************
                                          GLOBAL VARIABLES
**********************************************************************************************************/

OS_EXT  INT8U          y; //定义打印输出位置变量
OS_EXT  INT32U          OSCtxSwCtr;             /* Counter of number of context switches          */

#if (OS_EVENT_EN > 0) && (OS_MAX_EVENTS > 0)
OS_EXT  OS_EVENT       *OSEventFreeList;       /* Pointer to list of free EVENT control blocks */
OS_EXT  OS_EVENT       OSEventTbl[OS_MAX_EVENTS];/* Table of EVENT control blocks                */
#endif

在test.c中注释掉变量y

文件OS_SEM.C中的OSSemPend函数中添加红色部分代码
void  OSSemPend (OS_EVENT *pevent, INT16U timeout, INT8U *err)
{
#if OS_CRITICAL_METHOD == 3    /* Allocate storage for CPU status register    */
OS_CPU_SR  cpu_sr;
#endif
char str[25];

if (OSIntNesting > 0) {  /* See if called from ISR ... */
      *err = OS_ERR_PEND_ISR;  /* ... can't PEND from an ISR       */
      return;
}
#if OS_ARG_CHK_EN > 0
if (pevent == (OS_EVENT *)0) { /* Validate 'pevent'          */
      *err = OS_ERR_PEVENT_NULL;
      return;
}
if (pevent->OSEventType != OS_EVENT_TYPE_SEM) { /* Validate event block type  */
      *err = OS_ERR_EVENT_TYPE;
      return;
}
#endif
OS_ENTER_CRITICAL();
if (pevent->OSEventCnt > 0) { /* If sem. is positive, resource available ... */
      pevent->OSEventCnt--; /* ... decrement semaphore only if positive.    */
      OS_EXIT_CRITICAL();
      *err = OS_NO_ERR;

      sprintf(str, "task%d--resource count: %d", OSTCBCur->OSTCBPrio, pevent->OSEventCnt);
      PC_DispStr(15, y++, str, DISP_FGND_YELLOW+DISP_BGND_BLUE);

      return;
}
/* Otherwise, must wait until event occurs    */
OSTCBCur->OSTCBStat |= OS_STAT_SEM;  /* Resource not available, pend on semaphore    */
OSTCBCur->OSTCBDly = timeout;  /* Store pend timeout in TCB    */
OS_EventTaskWait(pevent); /* Suspend task until event or timeout occurs */
OS_EXIT_CRITICAL();

sprintf(str, "task%d--I'll wait", OSTCBCur->OSTCBPrio);
PC_DispStr(15, y++, str, DISP_FGND_YELLOW+DISP_BGND_BLUE);

OS_Sched();       /* Find next highest priority task ready       */
OS_ENTER_CRITICAL();
if (OSTCBCur->OSTCBStat & OS_STAT_SEM) { /* Must have timed out if still waiting for event*/
      OS_EventTO(pevent);
      OS_EXIT_CRITICAL();
      *err = OS_TIMEOUT; /* Indicate that didn't get event within TO    */

      sprintf(str, "task%d--time out", OSTCBCur->OSTCBPrio);
      PC_DispStr(15, y++, str, DISP_FGND_YELLOW+DISP_BGND_BLUE);

      return;
}
OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0;
OS_EXIT_CRITICAL();
sprintf(str, "task%d--finally get it", OSTCBCur->OSTCBPrio);
PC_DispStr(15, y++, str, DISP_FGND_YELLOW+DISP_BGND_BLUE);
*err = OS_NO_ERR;
}
文件OS_SEM.C中的OSSemPost函数中添加红色部分代码

INT8U  OSSemPost (OS_EVENT *pevent)
{
#if OS_CRITICAL_METHOD == 3    /* Allocate storage for CPU status register */
OS_CPU_SR  cpu_sr;
#endif
char str[25];

#if OS_ARG_CHK_EN > 0
if (pevent == (OS_EVENT *)0) {  /* Validate 'pevent'    */
      return (OS_ERR_PEVENT_NULL);
}
if (pevent->OSEventType != OS_EVENT_TYPE_SEM) { /* Validate event block type */
      return (OS_ERR_EVENT_TYPE);
}
#endif
OS_ENTER_CRITICAL();
if (pevent->OSEventGrp != 0x00) { /* See if any task waiting for semaphore */
      OS_EventTaskRdy(pevent, (void *)0, OS_STAT_SEM); /* Ready highest prio task waiting on event */
      OS_EXIT_CRITICAL();

      sprintf(str, "task%d--I'll Sched", OSTCBCur->OSTCBPrio);
      PC_DispStr(15, y++, str, DISP_FGND_YELLOW+DISP_BGND_BLUE);

      OS_Sched(); /* Find highest priority task ready to run  */

      sprintf(str, "task%d--back from Sched", OSTCBCur->OSTCBPrio);
      PC_DispStr(15, y++, str, DISP_FGND_YELLOW+DISP_BGND_BLUE);

      return (OS_NO_ERR);
}
if (pevent->OSEventCnt < 65535) { /* Make sure semaphore will not overflow */
      pevent->OSEventCnt++;    /* Increment semaphore count to register event */
      OS_EXIT_CRITICAL();

      sprintf(str, "task%d--resource count: %d", OSTCBCur->OSTCBPrio, pevent->OSEventCnt);
      PC_DispStr(15, y++, str, DISP_FGND_YELLOW+DISP_BGND_BLUE);

      return (OS_NO_ERR);
}
OS_EXIT_CRITICAL();    /* Semaphore value has reached its maximum    */

sprintf(str, "task%d--OS_SEM_OVF", OSTCBCur->OSTCBPrio);
PC_DispStr(15, y++, str, DISP_FGND_YELLOW+DISP_BGND_BLUE);

return (OS_SEM_OVF);
}

07-任务的同步与通信.zip

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