我使用Micro C OS II RTOS，我应该用"握手"来解决一个任务，但我不知道那是什么。我可以使用信号量，但我不知道握手是什么：
规范
通过握手相互通信的两个任务 程序。这两个任务都有 0 和 1 两种状态。在每种状态下，任务 应打印一条消息以指示活动任务的状态，例如 "任务 0 - 状态 0"，如果任务 0 处于状态 0。然后，程序应 显示以下执行模式 任务 0 - 状态 0 任务 1 - 状态 0 任务 1 - 状态 1 任务 0 - 状态 1 任务 0 - 状态 0 任务 1 - 状态 0 ...独立于任务周期。使用信号量求解 问题
该程序是
#include <stdio.h>
#include "includes.h"
#include <string.h>
#define DEBUG 1
/* 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
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: %dn",
prio, stk_data.OSFree, stk_data.OSUsed);
}
else
{
if (DEBUG == 1)
printf("Stack Check Error!n");
}
}
/* Prints a message and sleeps for given time interval */
void task1(void* pdata)
{
INT8U err;
while (1)
{
char text1[] = "Hello from Task1n";
int i;
OSSemPend(aSemaphore, 0, &err); // Trying to access the key
for (i = 0; i < strlen(text1); i++)
putchar(text1[i]);
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
}
}
/* Prints a message and sleeps for given time interval */
void task2(void* pdata)
{
INT8U err;
while (1)
{
char text2[] = "Hello from Task2n";
int i;
OSSemPend(aSemaphore, 0, &err); // Trying to access the key
for (i = 0; i < strlen(text2); i++)
putchar(text2[i]);
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 - Two Tasksn");
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;
}
我的解决方案
该程序具有正确的输出，但程序是否正确？
输出
Task 0 - State 0
Task 1 - State 0
Task 1 - State 1
Task 0 - State 1
Task 0 - State 0
Task 1 - State 0
Task 1 - State 1
。
握手。
#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
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: %dn",
prio, stk_data.OSFree, stk_data.OSUsed);
}
else
{
if (DEBUG == 1)
printf("Stack Check Error!n");
}
}
/* Prints a message and sleeps for given time interval */
void task1(void* pdata)
{
INT8U err;
char state = '1';
while (1)
{
char text1[] = "Task 0 - State ";
int i;
OSSemPend(aSemaphore, 0, &err); // Trying to access the key
for (i = 0; i < strlen(text1); i++)
putchar(text1[i]);
putchar(state);
putchar('n');
if (state=='0')
state='1';
else
state='0';
for (i = 0; i < strlen(text1); i++)
putchar(text1[i]);
putchar(state);
putchar('n');
if (state=='0')
state='1';
else
state='0';
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
}
}
/* Prints a message and sleeps for given time interval */
void task2(void* pdata)
{
INT8U err;
char state = '0';
while (1)
{
char text2[] = "Task 1 - State ";
int i;
OSSemPend(aSemaphore, 0, &err); // Trying to access the key
for (i = 0; i < strlen(text2); i++)
putchar(text2[i]);
putchar(state);
putchar('n');
if (state=='0')
state='1';
else
state='0';
for (i = 0; i < strlen(text2); i++)
putchar(text2[i]);
putchar(state);
putchar('n');
if (state=='0')
state='1';
else
state='0';
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 - Two Tasksn");
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;
}
这里的术语"握手"在分配的上下文中（以及更一般的）中具有含义，而不是特定于RTOS。
问题也是答案;它指出任务将通过握手过程进行通信，然后继续解释所需的握手过程。 也就是说，您不需要知道"握手"具体是什么，您只需要实现所描述的线程通信/同步（即握手）。
术语"握手"在双向同步协议的意义上具有一般含义，这就是作业继续描述的内容。它通常适用于在两个端点之间发生握手的通信协议，在这种情况下，它指的是两个线程的双向同步。
尽管如此，我必须说，所需握手协议的描述缺乏精确的清晰度;如果仍然不清楚，你可能应该要求你的导师澄清。