Add linked list operation

Core/Src/main.c

@@ -47,6 +47,7 @@ void SystemClock_Config(void)
 void Error_Handler(void)
 {
     __disable_irq();
+    printf("Error_Handler\r\n");
     while(1)
     {
     }
@@ -91,12 +92,9 @@ int main(void)
     init_task(&tcb1, prosee1, statck, (void *)&tcb1);
     init_task(&tcb2, prosee2, statck2, (void *)&tcb2);
 
-	/* run the first task */
-	start_first_task();
     __enable_irq();
     while(1)
     {
         printf("idle\r\n");
     };
 }
-

thead/src/context_switch.s

@@ -5,7 +5,6 @@
     AREA    |.text|, CODE, READONLY  ; 定义代码段
     EXPORT  PendSV_Handler           ; 导出 PendSV_Handler 符号
     IMPORT  current_task             ; 从 C 代码导入 current_task 指针
-    IMPORT  next_task                ; 从 C 代码导入 next_task 指针
     IMPORT  switch_to_next_task      ; 从 C 代码导入 switch_to_next_task 函数
 PendSV_Handler   PROC
 	

thead/src/thread.c

@@ -8,26 +8,14 @@
 	上下文切换的指针，如果触发了上下文切换，则next_task为下一个执行目标。
 ***/
 tcb_t *current_task;
-tcb_t *next_task;
+tcb_t *task_list = { 0 };
 
 /***
 	切换任务的函数，进行上下文切换的时候，会获取一下最新的任务指针。
 ***/
 void switch_to_next_task(void)
 {
-    tcb_t *temp = current_task;
-    current_task = next_task;
-    next_task = temp;
-}
-
-/***
-	启动切换，芯片上电默认执行的是main函数，需要切换到第一个任务上。
-***/
-void start_first_task(void)
-{
-    SCB->ICSR |= SCB_ICSR_PENDSVSET_Msk;
-    __DSB();
-    __ISB();
+    current_task = (current_task ? current_task : task_list)->next;
 }
 
 /***
@@ -36,14 +24,8 @@ void start_first_task(void)
 	2.采用时间片调度。
 	3.采用信号量调度。
 ***/
-tcb_t *task[2];
-uint8_t tcb_cunt = 0;
-static uint8_t max_tcb = 0;
 void tcb_scheduler(void)
 {
-    tcb_cunt = tcb_cunt % 2;
-    next_task = task[tcb_cunt];
-    tcb_cunt++;
     SCB->ICSR |= SCB_ICSR_PENDSVSET_Msk;
     __DSB();
     __ISB();
@@ -54,11 +36,9 @@ void tcb_scheduler(void)
 ***/
 void init_task(tcb_t *tcb, void (*task_entry)(void *), uint8_t *start_stack, void *arg)
 {
+    static tcb_t *task_first_list;
     // 栈顶对齐到 8 字节（硬件要求）
-    static uint8_t tcb_id = 0;
-    task[tcb_id] = tcb;
-    tcb_id++;
-    tcb->task_id = tcb_id;
+    tcb->task_id = task_list ? task_list->task_id + 1 : 1;
     tcb->stack_ptr = (uint32_t *)start_stack;
     uint32_t *stack_top = (uint32_t *)((uint8_t *)tcb->stack_ptr + STACK_SIZE);
     stack_top = (uint32_t *)((uint32_t)stack_top & ~0x07);
@@ -78,10 +58,17 @@ void init_task(tcb_t *tcb, void (*task_entry)(void *), uint8_t *start_stack, voi
     }
     tcb->stack_ptr = stack_top;
 
-    printf("init_tch:%d\r\n", tcb_id);
-    if(tcb_id == 1)
+    printf("init_tch:%d\r\n", tcb->task_id);
+    if(tcb->task_id == 1)
+    {
+        printf("start_tch:%d\r\n", tcb->task_id);
+        task_first_list = tcb;
+        task_list = tcb;
+    }
+    else
     {
-        printf("start_tch:%d\r\n", tcb_id);
-        next_task = tcb;
+        task_list->next = tcb;
+        tcb->next = task_first_list;
+        task_list = tcb;
     }
 }