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 IMPORT OS_CPU_SysTickHandler IMPORT OS_CPU_PendSVHandler __Vectors 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