c - 如何使用 Micro C OS II 同步两个任务？

Question

我有这个规范:

task 0 sends integer numbers (starting from 1) to task 1. Task 1 shall multiply the numbers with -1 and send them back to task 0. Task 0 shall then print these numbers to the console. For the communication between task 0 and task 1 a single memory location sharedAddress shall be used, i.e. both task 0 and task 1 read and write to/from this location! Save the file as SharedMemory.c. The execution of the program shall give the following output. Sending : 1 Receiving : -1 Sending : 2 Receiving : -2 ...

我写了这个程序，但任务没有正确同步，我想我可能在信号量或上下文切换方面做错了什么。

我得到这个输出，而不是数字有时倒计时，因为任务没有正确同步:

Receiving 17
Sending : 16
Receiving -16
Sending : -17
Receiving 17
Sending : 16
Receiving -16
Sending : -17
Receiving 17
Sending : 16
Receiving -16
Sending : -17
Receiving 17
Sending : 16
Receiving -16
Sending : -17
Receiving 17
Sending : 16
Receiving -16
Sending : -17
Receiving 17
Sending : 16
Receiving -16
Sending : -17
Receiving 17
Sending : 16
Receiving -16
Sending : -17
Receiving 17
Sending : 16
Receiving -16
Sending : -17
Receiving 17
Sending : 16
Receiving -16
Sending : -17
Receiving 17
Sending : 16
Receiving -16
Sending : -17
Receiving 17
Sending : 16
Receiving -16
Sending : -17
Receiving 17
Sending : 16
Receiving -16
Sending : -17
Receiving 17

我需要改的程序是

#include <stdio.h>
#include "includes.h"
#include <string.h>

#define DEBUG 0

/* Definition of Task Stacks */
/* Stack grows from HIGH to LOW memory */
#define   TASK_STACKSIZE       2048
OS_STK    task1_stk[TASK_STACKSIZE];
OS_STK    task2_stk[TASK_STACKSIZE];
OS_STK    stat_stk[TASK_STACKSIZE];
OS_EVENT *aSemaphore;
/* Definition of Task Priorities */
#define TASK1_PRIORITY      6  // highest priority
#define TASK2_PRIORITY      7
#define TASK_STAT_PRIORITY 12  // lowest priority 
int number = 1;
void handle_button_interrupts(void* context, alt_u32 id) 
{ 
 volatile int* edge_capture_ptr = (volatile int*) context; 

 OSIntEnter(); 
 // Read the edge capture register on the button PIO 
 //*edge_capture_ptr = 
 //IORD_ALTERA_AVALON_PIO_EDGE_CAP(BUTTON_PIO_BASE); 

 OSIntExit(); 
} 


void printStackSize(INT8U prio)
{
    INT8U err;
    OS_STK_DATA stk_data;

    err = OSTaskStkChk(prio, &stk_data);
    if (err == OS_NO_ERR) 
    {
        if (DEBUG == 1)
           printf("Task Priority %d - Used: %d; Free: %d\n", 
                   prio, stk_data.OSFree, stk_data.OSUsed);
    }
    else
    {
        if (DEBUG == 1)
           printf("Stack Check Error!\n");    
    }
}

/* Producer */
void task1(void* pdata)
{
  INT8U err;

  while (1)
  { 
    char text1[] = "Sending : ";
    char text2[] = "Receiving : ";

    int i;
    OSSemPend(aSemaphore, 0, &err); // Trying to access the key

    for (i = 0; i < strlen(text1); i++)
        putchar(text1[i]);
    printf("%d", number); 
    putchar('\n');   


    OSSemPost(aSemaphore); // Releasing the key
    OSTimeDlyHMSM(0, 0, 0, 11); // Context Switch to next task

                               // Task will go to the ready state

                               // after the specified delay


    OSSemPend(aSemaphore, 0, &err); // Trying to access the key

    for (i = 0; i < strlen(text1); i++)
        putchar(text2[i]);
    printf("%d", number); 
    putchar('\n');   
    number=-number;
    number++; 
    OSSemPost(aSemaphore); // Releasing the key
    OSTimeDlyHMSM(0, 0, 0, 11); // Context Switch to next task

                               // Task will go to the ready state

                               // after the specified delay


  }
}

/* Consumer */
void task2(void* pdata)
{
  INT8U err;  
  while (1)
  { 
    OSSemPend(aSemaphore, 0, &err); // Trying to access the key
    number = -number;
    OSSemPost(aSemaphore); // Releasing the key
    OSTimeDlyHMSM(0, 0, 0, 4);
  }
}

/* Printing Statistics */
void statisticTask(void* pdata)
{
    while(1)
    {
        printStackSize(TASK1_PRIORITY);
        printStackSize(TASK2_PRIORITY);
        printStackSize(TASK_STAT_PRIORITY);
    }
}

/* The main function creates two task and starts multi-tasking */
int main(void)
{
  printf("Lab 3 - Handshake\n");
  aSemaphore = OSSemCreate(1); // binary semaphore (1 key)
  OSTaskCreateExt
    (task1,                        // Pointer to task code
     NULL,                         // Pointer to argument that is
                                   // passed to task
     &task1_stk[TASK_STACKSIZE-1], // Pointer to top of task stack
     TASK1_PRIORITY,               // Desired Task priority
     TASK1_PRIORITY,               // Task ID
     &task1_stk[0],                // Pointer to bottom of task stack
     TASK_STACKSIZE,               // Stacksize
     NULL,                         // Pointer to user supplied memory
                                   // (not needed here)
     OS_TASK_OPT_STK_CHK |         // Stack Checking enabled 
     OS_TASK_OPT_STK_CLR           // Stack Cleared                                 
    );

  OSTaskCreateExt
    (task2,                        // Pointer to task code
     NULL,                         // Pointer to argument that is
                                   // passed to task
     &task2_stk[TASK_STACKSIZE-1], // Pointer to top of task stack
     TASK2_PRIORITY,               // Desired Task priority
     TASK2_PRIORITY,               // Task ID
     &task2_stk[0],                // Pointer to bottom of task stack
     TASK_STACKSIZE,               // Stacksize
     NULL,                         // Pointer to user supplied memory
                                   // (not needed here)
     OS_TASK_OPT_STK_CHK |         // Stack Checking enabled 
     OS_TASK_OPT_STK_CLR           // Stack Cleared                       
    );  

  if (DEBUG == 1)
  {
    OSTaskCreateExt
      (statisticTask,                // Pointer to task code
       NULL,                         // Pointer to argument that is
                                     // passed to task
       &stat_stk[TASK_STACKSIZE-1],  // Pointer to top of task stack
       TASK_STAT_PRIORITY,           // Desired Task priority
       TASK_STAT_PRIORITY,           // Task ID
       &stat_stk[0],                 // Pointer to bottom of task stack
       TASK_STACKSIZE,               // Stacksize
       NULL,                         // Pointer to user supplied memory
                                     // (not needed here)
       OS_TASK_OPT_STK_CHK |         // Stack Checking enabled 
       OS_TASK_OPT_STK_CLR           // Stack Cleared                              
      );
  }  

  OSStart();
  return 0;
}

你能帮帮我吗？

Answer 1

再想一想:您可能需要两个信号量:

• 一个用于从生产者发送到消费者 (sem1)
• 一个用于从消费者发送给生产者 (sem2)

你用 0 初始化 sem1，用 1 初始化 sem2。

• 任务 1 首先在 sem2 上挂起，然后处理数据并在 sem1 上发布。下一个循环步骤将等到任务 2 发布 sem2。
• 任务 2 在 sem 1 上挂起(因此等待第一个数据输入)，处理数据并在 sem2 上发布