STM32启动文件详细解析

一、STM32启动文件详细解析

STM32启动文件详细解析（V3.5.0） 以:startup_stm32f10x_hd.s为例

 ;******************** (C) COPYRIGHT 2011 STMicroelectronics ********************
 ;* File Name          : startup_stm32f10x_hd.s
 ;* Author             : MCD Application Team
 ;* Version            : V3.5.0
 ;* Date               : 11-March-2011
 ;* Description        : STM32F10x High Density Devices vector table for MDK-ARM
 ;*                      toolchain.
 ;*                      This module performs:
 ;*                      - Set the initial SP
 ;*                      - Set the initial PC == Reset_Handler
 ;*                      - Set the vector table entries with the exceptions ISR address
 ;*                      - Configure the clock system and also configure the external
 ;*                        SRAM mounted on STM3210E-EVAL board to be used as data
 ;*                        memory (optional, to be enabled by user)
 ;*                      - Branches to __main in the C library (which eventually
 ;*                        calls main()).
 ;*                      After Reset the CortexM3 processor is in Thread mode,
 ;*                      priority is Privileged, and the Stack is set to Main.
 ;* <<< Use Configuration Wizard in Context Menu >>>
 ;*******************************************************************************
 ; THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
 ; WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE TIME.
 ; AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY DIRECT,
 ; INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING FROM THE
 ; CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE CODING
 ; INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
 ;*******************************************************************************

 ; Amount of memory (in bytes) allocated for Stack
 ; Tailor this value to your application needs
 ;  Stack Configuration                     ;栈定义
 ;    Stack Size (in Bytes) <0x0-0xFFFFFFFF:8>
 ;

 Stack_Size      EQU     0x00000400              ;EQU伪指令，作用是左边的符号名代表右边的表达式

                 AREA    STACK, NOINIT, READWRITE, ALIGN=3   ;定义栈段：名称为STACK，未初始化，可读写，ELF 的栈段按2^3=8对齐
 Stack_Mem       SPACE   Stack_Size              ;分配一片连续的存储区域并初始化为 0，栈空间：0x400个字节
 __initial_sp                            ;栈空间顶地址


 ;  Heap Configuration                  ;堆定义
 ;     Heap Size (in Bytes) <0x0-0xFFFFFFFF:8>
 ;

 Heap_Size       EQU     0x00000200
                 AREA    HEAP, NOINIT, READWRITE, ALIGN=3

 __heap_base                         ;堆空间起始地址
 Heap_Mem        SPACE   Heap_Size               ;堆空间:0x200个字节
 __heap_limit                            ;堆空间结束地址


     PRESERVE8                       ;PRESERVE8 指令指定当前文件保持堆栈八字节对齐
     THUMB                           ;告诉汇编器下面是32位的Thumb指令，如果需要汇编器将插入位以保证对齐

 ; Vector Table Mapped to Address 0 at Reset         ;中断向量表定义
                                 ;实际上是在CODE区（假设STM32从FLASH启动，则此中断向量表起始地址即为0x8000000）
                 AREA    RESET, DATA, READONLY           ;定义一块数据段，只可读，段名字是RESET
                 EXPORT  __Vectors               ;EXPORT:在程序中声明一个全局的标号__Vectors，该标号可在其他的文件中引用
                 EXPORT  __Vectors_End               ;在程序中声明一个全局的标号__Vectors_End
                 EXPORT  __Vectors_Size              ;在程序中声明一个全局的标号__Vectors_Size

                                     ;DCD(DCDU)用于分配一片连续的字存储单元并用指定的数据初始化。
 __Vectors       DCD     __initial_sp               ; Top of Stack   ;该处物理地址值存储__initial_sp所表示的地址值,即为 __Vetors 标号所表示的值
                 DCD     Reset_Handler              ; Reset Handler
                 DCD     NMI_Handler                ; NMI Handler
                 DCD     HardFault_Handler          ; Hard Fault Handler
                 DCD     MemManage_Handler          ; MPU Fault Handler
                 DCD     BusFault_Handler           ; Bus Fault Handler
                 DCD     UsageFault_Handler         ; Usage Fault Handler
                 DCD     0                          ; Reserved
                 DCD     0                          ; Reserved
                 DCD     0                          ; Reserved
                 DCD     0                          ; Reserved
                 DCD     SVC_Handler                ; SVCall Handler
                 DCD     DebugMon_Handler           ; Debug Monitor Handler
                 DCD     0                          ; Reserved
                 DCD     PendSV_Handler             ; PendSV Handler
                 DCD     SysTick_Handler            ; SysTick Handler

                 ; External Interrupts                   ;以下为外部中断向量表
                 DCD     WWDG_IRQHandler            ; Window Watchdog
                 DCD     PVD_IRQHandler             ; PVD through EXTI Line detect
                 DCD     TAMPER_IRQHandler          ; Tamper
                 DCD     RTC_IRQHandler             ; RTC
                 DCD     FLASH_IRQHandler           ; Flash
                 DCD     RCC_IRQHandler             ; RCC
                 DCD     EXTI0_IRQHandler           ; EXTI Line 0
                 DCD     EXTI1_IRQHandler           ; EXTI Line 1
                 DCD     EXTI2_IRQHandler           ; EXTI Line 2
                 DCD     EXTI3_IRQHandler           ; EXTI Line 3
                 DCD     EXTI4_IRQHandler           ; EXTI Line 4
                 DCD     DMA1_Channel1_IRQHandler   ; DMA1 Channel 1
                 DCD     DMA1_Channel2_IRQHandler   ; DMA1 Channel 2
                 DCD     DMA1_Channel3_IRQHandler   ; DMA1 Channel 3
                 DCD     DMA1_Channel4_IRQHandler   ; DMA1 Channel 4
                 DCD     DMA1_Channel5_IRQHandler   ; DMA1 Channel 5
                 DCD     DMA1_Channel6_IRQHandler   ; DMA1 Channel 6
                 DCD     DMA1_Channel7_IRQHandler   ; DMA1 Channel 7
                 DCD     ADC1_2_IRQHandler          ; ADC1 & ADC2
                 DCD     USB_HP_CAN1_TX_IRQHandler  ; USB High Priority or CAN1 TX
                 DCD     USB_LP_CAN1_RX0_IRQHandler ; USB Low  Priority or CAN1 RX0
                 DCD     CAN1_RX1_IRQHandler        ; CAN1 RX1
                 DCD     CAN1_SCE_IRQHandler        ; CAN1 SCE
                 DCD     EXTI9_5_IRQHandler         ; EXTI Line 9..5
                 DCD     TIM1_BRK_IRQHandler        ; TIM1 Break
                 DCD     TIM1_UP_IRQHandler         ; TIM1 Update
                 DCD     TIM1_TRG_COM_IRQHandler    ; TIM1 Trigger and Commutation
                 DCD     TIM1_CC_IRQHandler         ; TIM1 Capture Compare
                 DCD     TIM2_IRQHandler            ; TIM2
                 DCD     TIM3_IRQHandler            ; TIM3
                 DCD     TIM4_IRQHandler            ; TIM4
                 DCD     I2C1_EV_IRQHandler         ; I2C1 Event
                 DCD     I2C1_ER_IRQHandler         ; I2C1 Error
                 DCD     I2C2_EV_IRQHandler         ; I2C2 Event
                 DCD     I2C2_ER_IRQHandler         ; I2C2 Error
                 DCD     SPI1_IRQHandler            ; SPI1
                 DCD     SPI2_IRQHandler            ; SPI2
                 DCD     USART1_IRQHandler          ; USART1
                 DCD     USART2_IRQHandler          ; USART2
                 DCD     USART3_IRQHandler          ; USART3
                 DCD     EXTI15_10_IRQHandler       ; EXTI Line 15..10
                 DCD     RTCAlarm_IRQHandler        ; RTC Alarm through EXTI Line
                 DCD     USBWakeUp_IRQHandler       ; USB Wakeup from suspend
                 DCD     TIM8_BRK_IRQHandler        ; TIM8 Break
                 DCD     TIM8_UP_IRQHandler         ; TIM8 Update
                 DCD     TIM8_TRG_COM_IRQHandler    ; TIM8 Trigger and Commutation
                 DCD     TIM8_CC_IRQHandler         ; TIM8 Capture Compare
                 DCD     ADC3_IRQHandler            ; ADC3
                 DCD     FSMC_IRQHandler            ; FSMC
                 DCD     SDIO_IRQHandler            ; SDIO
                 DCD     TIM5_IRQHandler            ; TIM5
                 DCD     SPI3_IRQHandler            ; SPI3
                 DCD     UART4_IRQHandler           ; UART4
                 DCD     UART5_IRQHandler           ; UART5
                 DCD     TIM6_IRQHandler            ; TIM6
                 DCD     TIM7_IRQHandler            ; TIM7
                 DCD     DMA2_Channel1_IRQHandler   ; DMA2 Channel1
                 DCD     DMA2_Channel2_IRQHandler   ; DMA2 Channel2
                 DCD     DMA2_Channel3_IRQHandler   ; DMA2 Channel3
                 DCD     DMA2_Channel4_5_IRQHandler ; DMA2 Channel4 & Channel5
 __Vectors_End                   ;Vectors结束

 __Vectors_Size  EQU  __Vectors_End - __Vectors      ;得到向量表的大小,304个字节也就是0x130个字节

                 AREA    |.text|, CODE, READONLY     ;定义一个代码段，可读，段名字是.text
                                     ;|.text|  用于表示由 C 编译程序产生的代码段，或用于以某种方式与 C 库关联的代码段
 ; Reset handler                     ;利用PROC、ENDP这一对伪指令标记程序开始、结束，把程序段分为若干个过程，使程序的结构加清晰
 Reset_Handler   PROC
                 EXPORT  Reset_Handler             [WEAK];WEAK声明其他的同名标号优先于该标号被引用,就是说如果外面声明了的话，调用外面的对应函数
                 IMPORT  __main              ;IMPORT:伪指令用于通知编译器要使用的标号在其他的源文件中定义
                 IMPORT  SystemInit
                 LDR     R0, =SystemInit         ;系统初始化
                 BLX     R0              ;带链接的跳转，切换指令集,跳到SystemInit
                 LDR     R0, =__main         ;__main为运行时库提供的函数；完成堆栈，堆的初始化等工作，会调用下面定义的__user_initial_stackheap
                 BX      R0              ;切换指令集,main函数不返回跳到__main,进入C的世界
                 ENDP

 ; Dummy Exception Handlers (infinite loops which can be modified)

 NMI_Handler     PROC
                 EXPORT  NMI_Handler                [WEAK];不可屏蔽中断处理函数
                 B       .
                 ENDP
 HardFault_Handler\                   ;\意为换行
                 PROC
                 EXPORT  HardFault_Handler          [WEAK];硬件错误处理函数
                 B       .
                 ENDP
 MemManage_Handler\
                 PROC
                 EXPORT  MemManage_Handler          [WEAK]
                 B       .
                 ENDP
 BusFault_Handler\
                 PROC
                 EXPORT  BusFault_Handler           [WEAK]
                 B       .
                 ENDP
 UsageFault_Handler\
                 PROC
                 EXPORT  UsageFault_Handler         [WEAK]
                 B       .
                 ENDP
 SVC_Handler     PROC
                 EXPORT  SVC_Handler                [WEAK]
                 B       .
                 ENDP
 DebugMon_Handler\
                 PROC
                 EXPORT  DebugMon_Handler           [WEAK]
                 B       .
                 ENDP
 PendSV_Handler  PROC
                 EXPORT  PendSV_Handler             [WEAK]
                 B       .
                 ENDP
 SysTick_Handler PROC
                 EXPORT  SysTick_Handler            [WEAK]
                 B       .
                 ENDP

 Default_Handler PROC
                             ;输出异常向量表标号,方便外部实现异常的具体功能,[WEAK]是弱定义的意思,如果外部定义了,优先执行外部定义,否则下面的函数定义
                 EXPORT  WWDG_IRQHandler            [WEAK]
                 EXPORT  PVD_IRQHandler             [WEAK]
                 EXPORT  TAMPER_IRQHandler          [WEAK]
                 EXPORT  RTC_IRQHandler             [WEAK]
                 EXPORT  FLASH_IRQHandler           [WEAK]
                 EXPORT  RCC_IRQHandler             [WEAK]
                 EXPORT  EXTI0_IRQHandler           [WEAK]
                 EXPORT  EXTI1_IRQHandler           [WEAK]
                 EXPORT  EXTI2_IRQHandler           [WEAK]
                 EXPORT  EXTI3_IRQHandler           [WEAK]
                 EXPORT  EXTI4_IRQHandler           [WEAK]
                 EXPORT  DMA1_Channel1_IRQHandler   [WEAK]
                 EXPORT  DMA1_Channel2_IRQHandler   [WEAK]
                 EXPORT  DMA1_Channel3_IRQHandler   [WEAK]
                 EXPORT  DMA1_Channel4_IRQHandler   [WEAK]
                 EXPORT  DMA1_Channel5_IRQHandler   [WEAK]
                 EXPORT  DMA1_Channel6_IRQHandler   [WEAK]
                 EXPORT  DMA1_Channel7_IRQHandler   [WEAK]
                 EXPORT  ADC1_2_IRQHandler          [WEAK]
                 EXPORT  USB_HP_CAN1_TX_IRQHandler  [WEAK]
                 EXPORT  USB_LP_CAN1_RX0_IRQHandler [WEAK]
                 EXPORT  CAN1_RX1_IRQHandler        [WEAK]
                 EXPORT  CAN1_SCE_IRQHandler        [WEAK]
                 EXPORT  EXTI9_5_IRQHandler         [WEAK]
                 EXPORT  TIM1_BRK_IRQHandler        [WEAK]
                 EXPORT  TIM1_UP_IRQHandler         [WEAK]
                 EXPORT  TIM1_TRG_COM_IRQHandler    [WEAK]
                 EXPORT  TIM1_CC_IRQHandler         [WEAK]
                 EXPORT  TIM2_IRQHandler            [WEAK]
                 EXPORT  TIM3_IRQHandler            [WEAK]
                 EXPORT  TIM4_IRQHandler            [WEAK]
                 EXPORT  I2C1_EV_IRQHandler         [WEAK]
                 EXPORT  I2C1_ER_IRQHandler         [WEAK]
                 EXPORT  I2C2_EV_IRQHandler         [WEAK]
                 EXPORT  I2C2_ER_IRQHandler         [WEAK]
                 EXPORT  SPI1_IRQHandler            [WEAK]
                 EXPORT  SPI2_IRQHandler            [WEAK]
                 EXPORT  USART1_IRQHandler          [WEAK]
                 EXPORT  USART2_IRQHandler          [WEAK]
                 EXPORT  USART3_IRQHandler          [WEAK]
                 EXPORT  EXTI15_10_IRQHandler       [WEAK]
                 EXPORT  RTCAlarm_IRQHandler        [WEAK]
                 EXPORT  USBWakeUp_IRQHandler       [WEAK]
                 EXPORT  TIM8_BRK_IRQHandler        [WEAK]
                 EXPORT  TIM8_UP_IRQHandler         [WEAK]
                 EXPORT  TIM8_TRG_COM_IRQHandler    [WEAK]
                 EXPORT  TIM8_CC_IRQHandler         [WEAK]
                 EXPORT  ADC3_IRQHandler            [WEAK]
                 EXPORT  FSMC_IRQHandler            [WEAK]
                 EXPORT  SDIO_IRQHandler            [WEAK]
                 EXPORT  TIM5_IRQHandler            [WEAK]
                 EXPORT  SPI3_IRQHandler            [WEAK]
                 EXPORT  UART4_IRQHandler           [WEAK]
                 EXPORT  UART5_IRQHandler           [WEAK]
                 EXPORT  TIM6_IRQHandler            [WEAK]
                 EXPORT  TIM7_IRQHandler            [WEAK]
                 EXPORT  DMA2_Channel1_IRQHandler   [WEAK]
                 EXPORT  DMA2_Channel2_IRQHandler   [WEAK]
                 EXPORT  DMA2_Channel3_IRQHandler   [WEAK]
                 EXPORT  DMA2_Channel4_5_IRQHandler [WEAK]
                             ;如下只是定义一些空函数
 WWDG_IRQHandler
 PVD_IRQHandler
 TAMPER_IRQHandler
 RTC_IRQHandler
 FLASH_IRQHandler
 RCC_IRQHandler
 EXTI0_IRQHandler
 EXTI1_IRQHandler
 EXTI2_IRQHandler
 EXTI3_IRQHandler
 EXTI4_IRQHandler
 DMA1_Channel1_IRQHandler
 DMA1_Channel2_IRQHandler
 DMA1_Channel3_IRQHandler
 DMA1_Channel4_IRQHandler
 DMA1_Channel5_IRQHandler
 DMA1_Channel6_IRQHandler
 DMA1_Channel7_IRQHandler
 ADC1_2_IRQHandler
 USB_HP_CAN1_TX_IRQHandler
 USB_LP_CAN1_RX0_IRQHandler
 CAN1_RX1_IRQHandler
 CAN1_SCE_IRQHandler
 EXTI9_5_IRQHandler
 TIM1_BRK_IRQHandler
 TIM1_UP_IRQHandler
 TIM1_TRG_COM_IRQHandler
 TIM1_CC_IRQHandler
 TIM2_IRQHandler
 TIM3_IRQHandler
 TIM4_IRQHandler
 I2C1_EV_IRQHandler
 I2C1_ER_IRQHandler
 I2C2_EV_IRQHandler
 I2C2_ER_IRQHandler
 SPI1_IRQHandler
 SPI2_IRQHandler
 USART1_IRQHandler
 USART2_IRQHandler
 USART3_IRQHandler
 EXTI15_10_IRQHandler
 RTCAlarm_IRQHandler
 USBWakeUp_IRQHandler
 TIM8_BRK_IRQHandler
 TIM8_UP_IRQHandler
 TIM8_TRG_COM_IRQHandler
 TIM8_CC_IRQHandler
 ADC3_IRQHandler
 FSMC_IRQHandler
 SDIO_IRQHandler
 TIM5_IRQHandler
 SPI3_IRQHandler
 UART4_IRQHandler
 UART5_IRQHandler
 TIM6_IRQHandler
 TIM7_IRQHandler
 DMA2_Channel1_IRQHandler
 DMA2_Channel2_IRQHandler
 DMA2_Channel3_IRQHandler
 DMA2_Channel4_5_IRQHandler
                 B       .

                 ENDP

                 ALIGN                   ;默认是字对齐方式，也说明了代码是4字节对齐的

 ;*******************************************************************************
 ; User Stack and Heap initialization 用户堆栈初始化
 ;*******************************************************************************
                  IF      :DEF:__MICROLIB        ;判断是否使用DEF:__MICROLIB（micro lib），如果勾选了micro lib

                  EXPORT  __initial_sp           ;将栈顶地址、堆起始地址、堆结束地址赋予全局属性，使外部程序可用
                  EXPORT  __heap_base
                  EXPORT  __heap_limit

                  ELSE                   ;如果没有勾选micro lib

                  IMPORT  __use_two_region_memory    ;两区堆栈空间，堆和栈有各自的空间地址
                  EXPORT  __user_initial_stackheap

 __user_initial_stackheap                ;标号__user_initial_stackheap，表示用户堆栈初始化程序入口
                             ;此处是初始化两区的堆栈空间，堆是从由低到高的增长，栈是由高向低生长的，两个是互相独立的数据段，并不能交叉使用。
                  LDR     R0, =  Heap_Mem        ;保存堆起始地址
                  LDR     R1, =(Stack_Mem + Stack_Size)  ;保存栈结束地址
                  LDR     R2, = (Heap_Mem +  Heap_Size)  ;保存堆结束地址
                  LDR     R3, = Stack_Mem        ;保存栈起始地址
                  BX      LR

                  ALIGN

                  ENDIF

                  END                    ;END命令指示汇编器,已到达一个源文件的末尾

 ;******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE*****

二、STM32 中断向量表的位置 、重定向

知道怎么跳到main函数了，那么，中断发生后，又是怎么跑到中断入口地址的呢？

从stm32f10x.s可以看到，已经定义好了一大堆的中断响应函数，这就是中断向量表，标号__Vectors，表示中断向量表入口地址，例如：

AREA    RESET, DATA, READONLY ; 定义只读数据段，实际上是在CODE区（假设STM32从FLASH启动，则此中断向量表起始地址即为0x8000000）

          EXPORT  __Vectors
  OS_CPU_SysTickHandler
 IMPORT  OS_CPU_PendSVHandler
 rs       DCD     __initial_sp              ; Top of Stack
          DCD     Reset_Handler             ; Reset Handler
          DCD     NMI_Handler               ; NMI Handler
          DCD     HardFault_Handler         ; Hard Fault Handler
          DCD     MemManage_Handler         ; MPU Fault Handler
          DCD     BusFault_Handler          ; Bus Fault Handler
          DCD     UsageFault_Handler        ; Usage Fault Handler

这个向量表的编写是有讲究的，跟硬件一一对应不能乱写的，CPU找入口地址就靠它了，bin文件开头就是他们的地址，参考手册RM0008的10.1.2节可以看到排列。

我们再结合CORTEX-M3的特性，他上电后根据boot引脚来决定PC位置，比如boot设置为flash启动，则启动后PC跳到0x08000000。此时CPU会先取2个地址，第一个是栈顶地址，第二个是复位异常地址，故有了上面的写法，这样就跳到reset_handler。

那么这个reset_handler的实际地址是多少.？下面的一堆例如Nmi_handler地址又是多少呢？发生中断是怎么跑到这个地址的呢？下面挨个讲解。

1、我们可以通过反向来得知这些入口地址，查看工程下的map文件就可以看到了，这个地址跟keil里面设置的target->flash起始地址息息相关，实际上我们不太需要关心，让编译器分配，中断向量表放的就是他们的地址。

2、对比ARM7/ARM9内核，Cortex-M3内核则是固定了中断向量表的位置而起始地址是可变化的。

3、进到C语言后会先配置NVIC，NVIC_SetVectorTable()里面可以配置中断向量表的起始地址和偏移，主要是告诉CPU该向量表是位于Flash还是Ram，偏移是多少。例如设置为位于Flash内，偏移就是烧入的程序地址，可在Keil target中设置。这样CPU就知道入口地址了。

4、发生中断后，CPU找到中断向量表地址，然后根据偏移（对号入座）再找到中断地址，这样就跳过去了。

我们截一个图说明一下，map文件：

对应的bin文件，看是不是放的上面地址：

显然，200039c0就是栈顶地址，而08006F21就是reset_handler地址！

如何定位？以放到0x20000000为例

1、keil设置ram起始为0x20000100，我们在0x20000000~0x20000100放中断向量表，其他给程序用

2、设置NVIC_SetVectorTable(NVIC_VectTab_FLASH,0);

3、跳到C时把中断向量表拷贝到0x20000000