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Rt-Thread 移植6--多线程（KF32)
6.1 就绪列表
6.1.1 线程就绪优先级组
线程优先级表的索引对应的线程的优先级。
为了快速的找到线程在线程优先级表的插入和移出的位置，RT-Thread专门设计了一个线程就绪优先级组。线程就绪优先组是一个32位的整型数，每一个位对应一个优先级，最多表示32个优先级rt_uint32_t rt_thread_ready_priority_group;- 1
6.1.2 寻找优先级最高的线程
从图中看出，第一个置1的位是位1，即表示此时就绪的线程当中，优先级最高的线程1，然后调度器从线程优先级表的索引1下去除线程1的线程控制块，从而切换到线程1.
kservice.c中const rt_uint8_t __lowest_bit_bitmap[] = { /* 00 */ 0, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 10 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 20 */ 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 30 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 40 */ 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 50 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 60 */ 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 70 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 80 */ 7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 90 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* A0 */ 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* B0 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* C0 */ 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* D0 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* E0 */ 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* F0 */ 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 }; /** * This function finds the first bit set (beginning with the least significant bit) * in value and return the index of that bit. * * Bits are numbered starting at 1 (the least significant bit). A return value of * zero from any of these functions means that the argument was zero. * * @return return the index of the first bit set. If value is 0, then this function * shall return 0. */ int __rt_ffs(int value) { if (value == 0) return 0; if (value & 0xff) return __lowest_bit_bitmap[value & 0xff] + 1; if (value & 0xff00) return __lowest_bit_bitmap[(value & 0xff00) >> 8] + 9; if (value & 0xff0000) return __lowest_bit_bitmap[(value & 0xff0000) >> 16] + 17; return __lowest_bit_bitmap[(value & 0xff000000) >> 24] + 25; }- 1
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6.1.3 线程优先级表
scheduler.c
rt_list_t rt_thread_priority_table[RT_THREAD_PRIORITY_MAX];- 1
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将线程插入到线程优先级表和移出分别由scheduler.c的rt_schedule_insert_thread()和rt_schedule_remove_thread（）这两个函数实现。void rt_schedule_insert_thread(struct rt_thread *thread) { register rt_base_t temp; /* disable interrupt */ temp = rt_hw_interrupt_disable(); /* change stat */ thread->stat = RT_THREAD_READY | (thread->stat & ~RT_THREAD_STAT_MASK); /* insert thread to ready list */ rt_list_insert_before(&(rt_thread_priority_table[thread->current_priority]), &(thread->tlist)); /* set priority mask */ #if RT_THREAD_PRIORITY_MAX > 32 rt_thread_ready_table[thread->number] |= thread->high_mask; #endif rt_thread_ready_priority_group |= thread->number_mask; P_DBG("insert thread %x grout %x\n",thread,rt_thread_ready_priority_group); /* enable interrupt */ rt_hw_interrupt_enable(temp); } /* * This function will remove a thread from system ready queue. * * @param thread the thread to be removed * * @note Please do not invoke this function in user application. */ void rt_schedule_remove_thread(struct rt_thread *thread) { register rt_base_t temp; /* disable interrupt */ temp = rt_hw_interrupt_disable(); /* remove thread from ready list */ rt_list_remove(&(thread->tlist)); if (rt_list_isempty(&(rt_thread_priority_table[thread->current_priority]))) { rt_thread_ready_priority_group &= ~thread->number_mask; } /* enable interrupt */ rt_hw_interrupt_enable(temp); }- 1
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6.2 修改代码
6.2.1 修改线程控制块
struct rt_thread { char name[RT_NAME_MAX]; rt_uint8_t type; rt_uint8_t flag; rt_list_t list; void *sp; /* 线程栈指针 */ void *entry; /* 线程入口地址 */ void *parameter; /* 线程形参 */ void *stack_addr; /* 线程起始地址 */ rt_uint32_t stack_size; /* 线程栈大小，单位为字节 */ rt_list_t tlist; /* 线程链表节点 */ #if TEST_USE_TICK_ENABLE rt_ubase_t init_tick; rt_ubase_t remaining_tick; #endif **rt_uint8_t current_priority; rt_uint8_t init_priority; rt_uint32_t number_mask; rt_err_t error; rt_uint8_t stat;** };- 1
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rtdef.h中定义错误码
#define RT_EOK 0 /**< There is no error */ #define RT_ERROR 1 /**< A generic error happens */ #define RT_ETIMEOUT 2 /**< Timed out */ #define RT_EFULL 3 /**< The resource is full */ #define RT_EEMPTY 4 /**< The resource is empty */ #define RT_ENOMEM 5 /**< No memory */ #define RT_ENOSYS 6 /**< No system */ #define RT_EBUSY 7 /**< Busy */ #define RT_EIO 8 /**< IO error */ #define RT_EINTR 9 /**< Interrupted system call */ #define RT_EINVAL 10 /**< Invalid argument */- 1
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定义线程状态
#define RT_THREAD_INIT 0x00 /**< Initialized status */ #define RT_THREAD_READY 0x01 /**< Ready status */ #define RT_THREAD_SUSPEND 0x02 /**< Suspend status */ #define RT_THREAD_RUNNING 0x03 /**< Running status */ #define RT_THREAD_BLOCK RT_THREAD_SUSPEND /**< Blocked status */ #define RT_THREAD_CLOSE 0x04 /**< Closed status */ #define RT_THREAD_STAT_MASK 0x0f- 1
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修改rt_system_scheduler_init()
void rt_system_scheduler_init(void) { register rt_base_t offset; for(offset = 0; offset < RT_THREAD_PRIORITY_MAX;offset++) { rt_list_init(&rt_thread_priority_table[offset]); } rt_current_priority = RT_THREAD_PRIORITY_MAX - 1; rt_current_thread = RT_NULL; rt_thread_ready_priority_group = 0; /* 初始化线程休眠列表，当线程创建好没有启动之前会被放入到这个列表 */ }- 1
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6.2.3 修改线程初始化函数rt_thread_init()
rt_err_t rt_thread_init(struct rt_thread *thread,const char *name, void (*entry)(void *parameter), void *parameter, void *stack_start, rt_uint32_t stack_size, **rt_uint8_t priority**) { rt_object_init((rt_object_t)thread,RT_Object_Class_Thread,name); rt_list_init(&(thread->tlist)); thread->entry = (void *)entry; thread->parameter = parameter; thread->stack_addr = stack_start; thread->stack_size = stack_size; /* 初始化线程栈，并返回线程栈指针 */ thread->sp = (void *)rt_hw_stack_init( thread->entry, thread->parameter, (void *)((char *)thread->stack_addr + thread->stack_size - 4) ); **thread->init_priority = priority; thread->current_priority = priority; thread->number_mask = 0; thread->error = RT_EOK; thread->stat = RT_THREAD_INIT;** }- 1
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6.2.4 添加线程启动函数rt_thread_startup()
rt_err_t rt_thread_startup(rt_thread_t thread) { thread->current_priority = thread->init_priority; thread->number_mask = 1L << thread->current_priority; thread->stat = RT_THREAD_SUSPEND; rt_thread_resume(thread); if(rt_thread_self() != RT_NULL) { rt_schedule(); } } rt_err_t rt_thread_resume(rt_thread_t thread) { register rt_base_t temp; if((thread->stat & RT_THREAD_STAT_MASK) != RT_THREAD_SUSPEND) { return -RT_ERROR; } temp = rt_hw_interrupt_disable(); rt_list_remove(&(thread->tlist)); rt_hw_interrupt_enable(temp); rt_schedule_insert_thread(thread); }- 1
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6.2.5 修改空闲线程初始化函数rt_thread_idle_init()
void rt_thread_idle_init(void) { rt_thread_init(&idle,"idle",rt_thread_idle_entry,RT_NULL,&rt_thread_stack[0],sizeof(rt_thread_stack),RT_THREAD_PRIORITY_MAX - 1); **rt_thread_startup(&idle);** }- 1
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6.2.6 修改启动系统调度器函数rt_system_scheduler_start()
不再是手动指定第一个需要运行的线程，而是根据优先级来决定第一个运行的线程。
void rt_system_scheduler_start(void) { register struct rt_thread *to_thread; register rt_ubase_t highest_ready_priority; highest_ready_priority = __rt_ffs(rt_thread_ready_priority_group)-1; P_DBG("first start pri %d\n",highest_ready_priority); to_thread = rt_list_entry(rt_thread_priority_table[highest_ready_priority].next,struct rt_thread,tlist); rt_current_thread = to_thread; rt_hw_context_switch_to((rt_uint32_t)&to_thread->sp); }- 1
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6.2.7 修改系统调度函数rt_schedule()
根据优先级来实现
void rt_schedule(void) { register rt_base_t temp; rt_base_t level; register rt_ubase_t highest_ready_priority; struct rt_thread *to_thread; struct rt_thread *from_thread; temp = rt_hw_interrupt_disable(); highest_ready_priority = __rt_ffs(rt_thread_ready_priority_group)-1; P_DBG("read pri %d\n",highest_ready_priority); to_thread = rt_list_entry(rt_thread_priority_table[highest_ready_priority].next,struct rt_thread,tlist); P_DBG("read tgread %x\n",to_thread); if(to_thread != rt_current_thread) { P_DBG("！= current thread %x\n",rt_current_thread); rt_current_priority = (rt_uint8_t) highest_ready_priority; from_thread = rt_current_thread; rt_current_thread = to_thread; rt_hw_context_switch((rt_uint32_t)&from_thread->sp,(rt_uint32_t)&to_thread->sp); rt_hw_interrupt_enable(temp); } else { rt_hw_interrupt_enable(temp); } /* 产生上下文切换 */ }- 1
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6.2.8 修改线程阻塞函数
void rt_thread_delay(rt_tick_t tick) { register rt_base_t temp; struct rt_thread *thread; temp = rt_hw_interrupt_disable(); thread = rt_current_thread; thread->remaining_tick = tick; thread->stat = RT_THREAD_SUSPEND; rt_thread_ready_priority_group &= ~thread->number_mask; rt_hw_interrupt_enable(temp); rt_schedule(); }- 1
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6.2.9 修改时基更i新函数rt_tick_increase()
void rt_tick_increase(void) { rt_ubase_t i; struct rt_thread *thread; rt_tick++; for(i = 0;i < RT_THREAD_PRIORITY_MAX;i++) { thread = rt_list_entry(rt_thread_priority_table[i].next,struct rt_thread,tlist); if(thread->remaining_tick > 0) { thread->remaining_tick--; if(thread->remaining_tick == 0) { rt_thread_ready_priority_group |= thread->number_mask; } } rt_schedule(); } }- 1
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6.3 main.c
/* 初始化线程 */ rt_thread_init( &rt_flag1_thread, "flag1", /* 线程控制块 */ flag1_thread_entry, /* 线程入口地址 */ RT_NULL, /* 线程形参 */ &rt_flag1_thread_stack[0], /* 线程栈起始地址 */ sizeof(rt_flag1_thread_stack),3 ); /* 线程栈大小，单位为字节 */ /* 将线程插入到就绪列表 */ //rt_list_insert_before( &(rt_thread_priority_table[0]),&(rt_flag1_thread.tlist) ); P_DBG("thread flag1 %x timer %s\n",&rt_flag1_thread,rt_flag1_thread.thread_timer.parent.name); rt_thread_startup(&rt_flag1_thread); /* 初始化线程 */ rt_thread_init( &rt_flag2_thread, "falg2", /* 线程控制块 */ flag2_thread_entry, /* 线程入口地址 */ RT_NULL, /* 线程形参 */ &rt_flag2_thread_stack[0], /* 线程栈起始地址 */ sizeof(rt_flag2_thread_stack),4 ); /* 线程栈大小，单位为字节 */ /* 将线程插入到就绪列表 */ P_DBG("thread flag1 %x timer %s\n",&rt_flag2_thread,rt_flag2_thread.thread_timer.parent.name); //rt_list_insert_before( &(rt_thread_priority_table[1]),&(rt_flag2_thread.tlist) ); rt_thread_startup(&rt_flag2_thread); /* 启动系统调度器 */ rt_system_scheduler_start(); /* 线程1 */ void flag1_thread_entry( void *p_arg ) { for( ;; ) { P_DBG("flag1 thread\n"); flag2 = 1; P_DBG("flag1 thread will dela1\n"); rt_thread_delay(10); flag2 = 0; P_DBG("flag1 thread will dela2\n"); rt_thread_delay(10); } } /* 线程2 */ void flag2_thread_entry( void *p_arg ) { for( ;; ) { P_DBG("flag2 thread\n"); flag2 = 1; rt_thread_delay(2); flag2 = 0; P_DBG("flag2 thread will dela1\n"); rt_thread_delay(2); } }- 1
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- 原文地址：https://blog.csdn.net/qq_43650963/article/details/134359653
