Cortex-M系列内核 启动文件分析
原文:https://www.cnblogs.com/w-smile/p/7738291.html
在开始之前先铺垫一下,启动文件里涉及到的汇编指令的用法
其中DCD 相当于C语言力的&,定义地址。
启动文所做的操作主要有:
- 初始化栈
- 初始化堆
- 初始化中断向量表
- 系统初始化
- 函数声明
1,初始化栈
Stack_Size EQU 0x00000400 :0x00000400=1024 AREA STACK, NOINIT, READWRITE, ALIGN=3 Stack_Mem SPACE Stack_Size __initial_sp
其中第二行汇编了数据段STACK 其中 NOINIT 表示未初始化,READWRITE可读可写,ALLGN 2*3 = 8 八字节对齐,第三行为STACK分配了大小为1KB的内存空间,紧跟着后面的__initial_sp 因为其是紧跟着栈分配内存后所以其为栈顶(递减栈)。最终__init_sp为1KB空间栈的栈顶,栈主要用于函数局部变量和形参的及调用过程的临时存储,属于编译器自动分配和释放的内存,所以这里需要注意如果你的函数所占的内存大过这个空间应调整其大小但一定要小于内部SARM的大小。堆是程序员进行分配和释放的,如果程序中未释放最后由系统回收。
2,初始化堆
Heap_Size EQU 0x00000200 ;0x00000200 = 1000 AREA HEAP, NOINIT, READWRITE, ALIGN=3 __heap_base Heap_Mem SPACE Heap_Size __heap_limit PRESERVE8 THUMB
其中第二行汇编了一个数据段HEAP NOINIT 未初始化,READWRITE可读可写,ALLGN 2*3 = 8 八字节对齐,第三行定义堆的起始地址 __heap_base 接下来就按汇编的数据类型和大小分配堆的1000B内存同样 __heap_limit就为堆的最后一个地址。对于内存可以看这个博客:http://blog.csdn.net/qq_29119171/article/details/53764823
PRESERVE8 编译器指令8字节对齐
THUMB 选择芯片的指令集到此堆初始化完成。
2,初始化中断向量表
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
; Vector Table Mapped to Address 0 at Reset AREA RESET, DATA, READONLY EXPORT __Vectors EXPORT __Vectors_End EXPORT __Vectors_Size __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 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 DCD WWDG_IRQHandler ; Window WatchDog DCD PVD_IRQHandler ; PVD through EXTI Line detection DCD TAMP_STAMP_IRQHandler ; Tamper and TimeStamps through the EXTI line DCD RTC_WKUP_IRQHandler ; RTC Wakeup through the EXTI line DCD FLASH_IRQHandler ; FLASH DCD RCC_IRQHandler ; RCC DCD EXTI0_IRQHandler ; EXTI Line0 DCD EXTI1_IRQHandler ; EXTI Line1 DCD EXTI2_IRQHandler ; EXTI Line2 DCD EXTI3_IRQHandler ; EXTI Line3 DCD EXTI4_IRQHandler ; EXTI Line4 DCD DMA1_Stream0_IRQHandler ; DMA1 Stream 0 DCD DMA1_Stream1_IRQHandler ; DMA1 Stream 1 DCD DMA1_Stream2_IRQHandler ; DMA1 Stream 2 DCD DMA1_Stream3_IRQHandler ; DMA1 Stream 3 DCD DMA1_Stream4_IRQHandler ; DMA1 Stream 4 DCD DMA1_Stream5_IRQHandler ; DMA1 Stream 5 DCD DMA1_Stream6_IRQHandler ; DMA1 Stream 6 DCD ADC_IRQHandler ; ADC1, ADC2 and ADC3s DCD CAN1_TX_IRQHandler ; CAN1 TX DCD CAN1_RX0_IRQHandler ; CAN1 RX0 DCD CAN1_RX1_IRQHandler ; CAN1 RX1 DCD CAN1_SCE_IRQHandler ; CAN1 SCE DCD EXTI9_5_IRQHandler ; External Line[9:5]s DCD TIM1_BRK_TIM9_IRQHandler ; TIM1 Break and TIM9 DCD TIM1_UP_TIM10_IRQHandler ; TIM1 Update and TIM10 DCD TIM1_TRG_COM_TIM11_IRQHandler ; TIM1 Trigger and Commutation and TIM11 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 ; External Line[15:10]s DCD RTC_Alarm_IRQHandler ; RTC Alarm (A and B) through EXTI Line DCD OTG_FS_WKUP_IRQHandler ; USB OTG FS Wakeup through EXTI line DCD TIM8_BRK_TIM12_IRQHandler ; TIM8 Break and TIM12 DCD TIM8_UP_TIM13_IRQHandler ; TIM8 Update and TIM13 DCD TIM8_TRG_COM_TIM14_IRQHandler ; TIM8 Trigger and Commutation and TIM14 DCD TIM8_CC_IRQHandler ; TIM8 Capture Compare DCD DMA1_Stream7_IRQHandler ; DMA1 Stream7 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_DAC_IRQHandler ; TIM6 and DAC1&2 underrun errors DCD TIM7_IRQHandler ; TIM7 DCD DMA2_Stream0_IRQHandler ; DMA2 Stream 0 DCD DMA2_Stream1_IRQHandler ; DMA2 Stream 1 DCD DMA2_Stream2_IRQHandler ; DMA2 Stream 2 DCD DMA2_Stream3_IRQHandler ; DMA2 Stream 3 DCD DMA2_Stream4_IRQHandler ; DMA2 Stream 4 DCD ETH_IRQHandler ; Ethernet DCD ETH_WKUP_IRQHandler ; Ethernet Wakeup through EXTI line DCD CAN2_TX_IRQHandler ; CAN2 TX DCD CAN2_RX0_IRQHandler ; CAN2 RX0 DCD CAN2_RX1_IRQHandler ; CAN2 RX1 DCD CAN2_SCE_IRQHandler ; CAN2 SCE DCD OTG_FS_IRQHandler ; USB OTG FS DCD DMA2_Stream5_IRQHandler ; DMA2 Stream 5 DCD DMA2_Stream6_IRQHandler ; DMA2 Stream 6 DCD DMA2_Stream7_IRQHandler ; DMA2 Stream 7 DCD USART6_IRQHandler ; USART6 DCD I2C3_EV_IRQHandler ; I2C3 event DCD I2C3_ER_IRQHandler ; I2C3 error DCD OTG_HS_EP1_OUT_IRQHandler ; USB OTG HS End Point 1 Out DCD OTG_HS_EP1_IN_IRQHandler ; USB OTG HS End Point 1 In DCD OTG_HS_WKUP_IRQHandler ; USB OTG HS Wakeup through EXTI DCD OTG_HS_IRQHandler ; USB OTG HS DCD DCMI_IRQHandler ; DCMI DCD CRYP_IRQHandler ; CRYP crypto DCD HASH_RNG_IRQHandler ; Hash and Rng DCD FPU_IRQHandler ; FPU __Vectors_End __Vectors_Size EQU __Vectors_End - __Vectors
这是一个中断向量表,向量表从FLASH 的0x00000000 地址开始放置,以4 个字节为一个单位,地址0 存放的是栈顶(sp_init)地址,0X00000004 存放的是复位程序的地址,以此类推。从代码上看,向量表中存放的都是中断服务函数的函数名,可我们知道C 语言中的函数名就是一个地址。(由此知道,中断函数的函数名都已经知道了)。 从那里对应地址取出服务例程的入口地址并跳入。要注意的是这里有个另类:0 号类型并不是什么入口地址,而是给出了复位后MSP 的初值。
3.系统初始化函数及中断函数声明
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
AREA |.text|, CODE, READONLY ; Reset handler Reset_Handler PROC EXPORT Reset_Handler [WEAK] IMPORT SystemInit IMPORT __main LDR R0, =SystemInit BLX R0 LDR R0, =__main BX R0 ENDP ; Dummy Exception Handlers (infinite loops which can be modified) NMI_Handler PROC EXPORT NMI_Handler [WEAK] B . ENDP HardFault_Handler\ PROC EXPORT HardFault_Handler [WEAK] 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 EXPORT WWDG_IRQHandler [WEAK] EXPORT PVD_IRQHandler [WEAK] EXPORT TAMP_STAMP_IRQHandler [WEAK] EXPORT RTC_WKUP_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_Stream0_IRQHandler [WEAK] EXPORT DMA1_Stream1_IRQHandler [WEAK] EXPORT DMA1_Stream2_IRQHandler [WEAK] EXPORT DMA1_Stream3_IRQHandler [WEAK] EXPORT DMA1_Stream4_IRQHandler [WEAK] EXPORT DMA1_Stream5_IRQHandler [WEAK] EXPORT DMA1_Stream6_IRQHandler [WEAK] EXPORT ADC_IRQHandler [WEAK] EXPORT CAN1_TX_IRQHandler [WEAK] EXPORT CAN1_RX0_IRQHandler [WEAK] EXPORT CAN1_RX1_IRQHandler [WEAK] EXPORT CAN1_SCE_IRQHandler [WEAK] EXPORT EXTI9_5_IRQHandler [WEAK] EXPORT TIM1_BRK_TIM9_IRQHandler [WEAK] EXPORT TIM1_UP_TIM10_IRQHandler [WEAK] EXPORT TIM1_TRG_COM_TIM11_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 RTC_Alarm_IRQHandler [WEAK] EXPORT OTG_FS_WKUP_IRQHandler [WEAK] EXPORT TIM8_BRK_TIM12_IRQHandler [WEAK] EXPORT TIM8_UP_TIM13_IRQHandler [WEAK] EXPORT TIM8_TRG_COM_TIM14_IRQHandler [WEAK] EXPORT TIM8_CC_IRQHandler [WEAK] EXPORT DMA1_Stream7_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_DAC_IRQHandler [WEAK] EXPORT TIM7_IRQHandler [WEAK] EXPORT DMA2_Stream0_IRQHandler [WEAK] EXPORT DMA2_Stream1_IRQHandler [WEAK] EXPORT DMA2_Stream2_IRQHandler [WEAK] EXPORT DMA2_Stream3_IRQHandler [WEAK] EXPORT DMA2_Stream4_IRQHandler [WEAK] EXPORT ETH_IRQHandler [WEAK] EXPORT ETH_WKUP_IRQHandler [WEAK] EXPORT CAN2_TX_IRQHandler [WEAK] EXPORT CAN2_RX0_IRQHandler [WEAK] EXPORT CAN2_RX1_IRQHandler [WEAK] EXPORT CAN2_SCE_IRQHandler [WEAK] EXPORT OTG_FS_IRQHandler [WEAK] EXPORT DMA2_Stream5_IRQHandler [WEAK] EXPORT DMA2_Stream6_IRQHandler [WEAK] EXPORT DMA2_Stream7_IRQHandler [WEAK] EXPORT USART6_IRQHandler [WEAK] EXPORT I2C3_EV_IRQHandler [WEAK] EXPORT I2C3_ER_IRQHandler [WEAK] EXPORT OTG_HS_EP1_OUT_IRQHandler [WEAK] EXPORT OTG_HS_EP1_IN_IRQHandler [WEAK] EXPORT OTG_HS_WKUP_IRQHandler [WEAK] EXPORT OTG_HS_IRQHandler [WEAK] EXPORT DCMI_IRQHandler [WEAK] EXPORT CRYP_IRQHandler [WEAK] EXPORT HASH_RNG_IRQHandler [WEAK] EXPORT FPU_IRQHandler [WEAK] //如下定义一个空函数 WWDG_IRQHandler PVD_IRQHandler TAMP_STAMP_IRQHandler RTC_WKUP_IRQHandler FLASH_IRQHandler RCC_IRQHandler EXTI0_IRQHandler EXTI1_IRQHandler EXTI2_IRQHandler EXTI3_IRQHandler EXTI4_IRQHandler DMA1_Stream0_IRQHandler DMA1_Stream1_IRQHandler DMA1_Stream2_IRQHandler DMA1_Stream3_IRQHandler DMA1_Stream4_IRQHandler DMA1_Stream5_IRQHandler DMA1_Stream6_IRQHandler ADC_IRQHandler CAN1_TX_IRQHandler CAN1_RX0_IRQHandler CAN1_RX1_IRQHandler CAN1_SCE_IRQHandler EXTI9_5_IRQHandler TIM1_BRK_TIM9_IRQHandler TIM1_UP_TIM10_IRQHandler TIM1_TRG_COM_TIM11_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 RTC_Alarm_IRQHandler OTG_FS_WKUP_IRQHandler TIM8_BRK_TIM12_IRQHandler TIM8_UP_TIM13_IRQHandler TIM8_TRG_COM_TIM14_IRQHandler TIM8_CC_IRQHandler DMA1_Stream7_IRQHandler FSMC_IRQHandler SDIO_IRQHandler TIM5_IRQHandler SPI3_IRQHandler UART4_IRQHandler UART5_IRQHandler TIM6_DAC_IRQHandler TIM7_IRQHandler DMA2_Stream0_IRQHandler DMA2_Stream1_IRQHandler DMA2_Stream2_IRQHandler DMA2_Stream3_IRQHandler DMA2_Stream4_IRQHandler ETH_IRQHandler ETH_WKUP_IRQHandler CAN2_TX_IRQHandler CAN2_RX0_IRQHandler CAN2_RX1_IRQHandler CAN2_SCE_IRQHandler OTG_FS_IRQHandler DMA2_Stream5_IRQHandler DMA2_Stream6_IRQHandler DMA2_Stream7_IRQHandler USART6_IRQHandler I2C3_EV_IRQHandler I2C3_ER_IRQHandler OTG_HS_EP1_OUT_IRQHandler OTG_HS_EP1_IN_IRQHandler OTG_HS_WKUP_IRQHandler OTG_HS_IRQHandler DCMI_IRQHandler CRYP_IRQHandler HASH_RNG_IRQHandler FPU_IRQHandler
AREA |.text|, CODE, READONLY定义一个名称为.text 的代码段,可读程序段。
PROC与ENDP组合在汇编中定义一段子函数
类似与这种形式:EXPORT FPU_IRQHandler [WEAK]的用法,其中WEAK是弱定义的意思,如果外部定义了就先使用外部定义的内容,若未定义则会执行地下的空函数且返回到空函数(死循环)。
4.用户堆栈的初始化
这以部分也就是把初始化的堆栈地址赋值给单片机的对应寄存器以方便C程序进行分配释放使用。
User Stack and Heap initialization ;******************************************************************************* IF :DEF:__MICROLIB //这一部分是关于是否使用微库 EXPORT __initial_sp EXPORT __heap_base EXPORT __heap_limit ELSE IMPORT __use_two_region_memory EXPORT __user_initial_stackheap __user_initial_stackheap LDR R0, = Heap_Mem LDR R1, =(Stack_Mem + Stack_Size) LDR R2, = (Heap_Mem + Heap_Size) LDR R3, = Stack_Mem BX LR ALIGN ENDIF END
使用微库与不使用微库的区别(参考:http://www.cnblogs.com/amanlikethis/p/3719529.html)
使用微库就意味着我们不想使用MDK提供的库函数,而想用自己定义的库函数,比如说printf函数。那么这一点是怎样实现的呢?我们以printf函数为例进行说明。不使用微库而使用系统库在连接程序时,肯定会把系统中包含printf函数的库拿来调用参与连接,即代码段有系统库的参与。在启动过程中,不使用微库而使用系统库在初始化栈的时候,还需要初始化堆(猜测系统库需要用到堆),而使用微库则是不需要的。另外,在执行__main函数的过程中,不仅需要完成“使用微库”情况下的所有工作,额外的工作还需要进行库的初始化,才能使用系统库(这一部分我还没有深入)。使用微库而不使用系统库在程序连接时,不会把包含printf函数的库连接到终极目标文件中,而使用我们定义的库。启动时需要完成的工作就是之前论述的步骤相比使用系统库,启动过程步骤更少。
6.总结
启动文件XXX.s从头开始执行,(C语言上分为栈、堆、.bss、.data、.code段)依次定义了栈,堆,代码段|.text|,初始化向量表后又初始化了系统的时钟的及C函数的跳转,其中__main 是一个标准的C 库函数,主要作用是初始化用户堆栈(初始化数据段在.data段,未初始化数据段在.bss数据段上)最终调用main 函数。还需要清楚的一点是假设STM32被设置为从内部FLASH启动中断向量表起始地位为0x8000000; 则栈顶地址存放于0x8000000处,而复位中断服务入口地址存放于0x8000004处。当STM32到复位信号后,则从0x80000004处取出复位中断服务入口地址继而执行复位中断服务程序,; 然后跳转__main函数最后在——main()函数的引导下进入C语言的用户main()函数开始执行。
在开始之前先铺垫一下,启动文件里涉及到的汇编指令的用法
其中DCD 相当于C语言力的&,定义地址。
启动文所做的操作主要有:
- 初始化栈
- 初始化堆
- 初始化中断向量表
- 系统初始化
- 函数声明
1,初始化栈
Stack_Size EQU 0x00000400 :0x00000400=1024 AREA STACK, NOINIT, READWRITE, ALIGN=3 Stack_Mem SPACE Stack_Size __initial_sp
其中第二行汇编了数据段STACK 其中 NOINIT 表示未初始化,READWRITE可读可写,ALLGN 2*3 = 8 八字节对齐,第三行为STACK分配了大小为1KB的内存空间,紧跟着后面的__initial_sp 因为其是紧跟着栈分配内存后所以其为栈顶(递减栈)。最终__init_sp为1KB空间栈的栈顶,栈主要用于函数局部变量和形参的及调用过程的临时存储,属于编译器自动分配和释放的内存,所以这里需要注意如果你的函数所占的内存大过这个空间应调整其大小但一定要小于内部SARM的大小。堆是程序员进行分配和释放的,如果程序中未释放最后由系统回收。
2,初始化堆
Heap_Size EQU 0x00000200 ;0x00000200 = 1000 AREA HEAP, NOINIT, READWRITE, ALIGN=3 __heap_base Heap_Mem SPACE Heap_Size __heap_limit PRESERVE8 THUMB
其中第二行汇编了一个数据段HEAP NOINIT 未初始化,READWRITE可读可写,ALLGN 2*3 = 8 八字节对齐,第三行定义堆的起始地址 __heap_base 接下来就按汇编的数据类型和大小分配堆的1000B内存同样 __heap_limit就为堆的最后一个地址。对于内存可以看这个博客:http://blog.csdn.net/qq_29119171/article/details/53764823
PRESERVE8 编译器指令8字节对齐
THUMB 选择芯片的指令集到此堆初始化完成。
2,初始化中断向量表
![](https://images.cnblogs.com/OutliningIndicators/ExpandedBlockStart.gif)
; Vector Table Mapped to Address 0 at Reset AREA RESET, DATA, READONLY EXPORT __Vectors EXPORT __Vectors_End EXPORT __Vectors_Size __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 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 DCD WWDG_IRQHandler ; Window WatchDog DCD PVD_IRQHandler ; PVD through EXTI Line detection DCD TAMP_STAMP_IRQHandler ; Tamper and TimeStamps through the EXTI line DCD RTC_WKUP_IRQHandler ; RTC Wakeup through the EXTI line DCD FLASH_IRQHandler ; FLASH DCD RCC_IRQHandler ; RCC DCD EXTI0_IRQHandler ; EXTI Line0 DCD EXTI1_IRQHandler ; EXTI Line1 DCD EXTI2_IRQHandler ; EXTI Line2 DCD EXTI3_IRQHandler ; EXTI Line3 DCD EXTI4_IRQHandler ; EXTI Line4 DCD DMA1_Stream0_IRQHandler ; DMA1 Stream 0 DCD DMA1_Stream1_IRQHandler ; DMA1 Stream 1 DCD DMA1_Stream2_IRQHandler ; DMA1 Stream 2 DCD DMA1_Stream3_IRQHandler ; DMA1 Stream 3 DCD DMA1_Stream4_IRQHandler ; DMA1 Stream 4 DCD DMA1_Stream5_IRQHandler ; DMA1 Stream 5 DCD DMA1_Stream6_IRQHandler ; DMA1 Stream 6 DCD ADC_IRQHandler ; ADC1, ADC2 and ADC3s DCD CAN1_TX_IRQHandler ; CAN1 TX DCD CAN1_RX0_IRQHandler ; CAN1 RX0 DCD CAN1_RX1_IRQHandler ; CAN1 RX1 DCD CAN1_SCE_IRQHandler ; CAN1 SCE DCD EXTI9_5_IRQHandler ; External Line[9:5]s DCD TIM1_BRK_TIM9_IRQHandler ; TIM1 Break and TIM9 DCD TIM1_UP_TIM10_IRQHandler ; TIM1 Update and TIM10 DCD TIM1_TRG_COM_TIM11_IRQHandler ; TIM1 Trigger and Commutation and TIM11 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 ; External Line[15:10]s DCD RTC_Alarm_IRQHandler ; RTC Alarm (A and B) through EXTI Line DCD OTG_FS_WKUP_IRQHandler ; USB OTG FS Wakeup through EXTI line DCD TIM8_BRK_TIM12_IRQHandler ; TIM8 Break and TIM12 DCD TIM8_UP_TIM13_IRQHandler ; TIM8 Update and TIM13 DCD TIM8_TRG_COM_TIM14_IRQHandler ; TIM8 Trigger and Commutation and TIM14 DCD TIM8_CC_IRQHandler ; TIM8 Capture Compare DCD DMA1_Stream7_IRQHandler ; DMA1 Stream7 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_DAC_IRQHandler ; TIM6 and DAC1&2 underrun errors DCD TIM7_IRQHandler ; TIM7 DCD DMA2_Stream0_IRQHandler ; DMA2 Stream 0 DCD DMA2_Stream1_IRQHandler ; DMA2 Stream 1 DCD DMA2_Stream2_IRQHandler ; DMA2 Stream 2 DCD DMA2_Stream3_IRQHandler ; DMA2 Stream 3 DCD DMA2_Stream4_IRQHandler ; DMA2 Stream 4 DCD ETH_IRQHandler ; Ethernet DCD ETH_WKUP_IRQHandler ; Ethernet Wakeup through EXTI line DCD CAN2_TX_IRQHandler ; CAN2 TX DCD CAN2_RX0_IRQHandler ; CAN2 RX0 DCD CAN2_RX1_IRQHandler ; CAN2 RX1 DCD CAN2_SCE_IRQHandler ; CAN2 SCE DCD OTG_FS_IRQHandler ; USB OTG FS DCD DMA2_Stream5_IRQHandler ; DMA2 Stream 5 DCD DMA2_Stream6_IRQHandler ; DMA2 Stream 6 DCD DMA2_Stream7_IRQHandler ; DMA2 Stream 7 DCD USART6_IRQHandler ; USART6 DCD I2C3_EV_IRQHandler ; I2C3 event DCD I2C3_ER_IRQHandler ; I2C3 error DCD OTG_HS_EP1_OUT_IRQHandler ; USB OTG HS End Point 1 Out DCD OTG_HS_EP1_IN_IRQHandler ; USB OTG HS End Point 1 In DCD OTG_HS_WKUP_IRQHandler ; USB OTG HS Wakeup through EXTI DCD OTG_HS_IRQHandler ; USB OTG HS DCD DCMI_IRQHandler ; DCMI DCD CRYP_IRQHandler ; CRYP crypto DCD HASH_RNG_IRQHandler ; Hash and Rng DCD FPU_IRQHandler ; FPU __Vectors_End __Vectors_Size EQU __Vectors_End - __Vectors
这是一个中断向量表,向量表从FLASH 的0x00000000 地址开始放置,以4 个字节为一个单位,地址0 存放的是栈顶(sp_init)地址,0X00000004 存放的是复位程序的地址,以此类推。从代码上看,向量表中存放的都是中断服务函数的函数名,可我们知道C 语言中的函数名就是一个地址。(由此知道,中断函数的函数名都已经知道了)。 从那里对应地址取出服务例程的入口地址并跳入。要注意的是这里有个另类:0 号类型并不是什么入口地址,而是给出了复位后MSP 的初值。
3.系统初始化函数及中断函数声明
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
AREA |.text|, CODE, READONLY定义一个名称为.text 的代码段,可读程序段。
PROC与ENDP组合在汇编中定义一段子函数
类似与这种形式:EXPORT FPU_IRQHandler [WEAK]的用法,其中WEAK是弱定义的意思,如果外部定义了就先使用外部定义的内容,若未定义则会执行地下的空函数且返回到空函数(死循环)。
4.用户堆栈的初始化
这以部分也就是把初始化的堆栈地址赋值给单片机的对应寄存器以方便C程序进行分配释放使用。
User Stack and Heap initialization ;******************************************************************************* IF :DEF:__MICROLIB //这一部分是关于是否使用微库 EXPORT __initial_sp EXPORT __heap_base EXPORT __heap_limit ELSE IMPORT __use_two_region_memory EXPORT __user_initial_stackheap __user_initial_stackheap LDR R0, = Heap_Mem LDR R1, =(Stack_Mem + Stack_Size) LDR R2, = (Heap_Mem + Heap_Size) LDR R3, = Stack_Mem BX LR ALIGN ENDIF END
使用微库与不使用微库的区别(参考:http://www.cnblogs.com/amanlikethis/p/3719529.html)
使用微库就意味着我们不想使用MDK提供的库函数,而想用自己定义的库函数,比如说printf函数。那么这一点是怎样实现的呢?我们以printf函数为例进行说明。不使用微库而使用系统库在连接程序时,肯定会把系统中包含printf函数的库拿来调用参与连接,即代码段有系统库的参与。在启动过程中,不使用微库而使用系统库在初始化栈的时候,还需要初始化堆(猜测系统库需要用到堆),而使用微库则是不需要的。另外,在执行__main函数的过程中,不仅需要完成“使用微库”情况下的所有工作,额外的工作还需要进行库的初始化,才能使用系统库(这一部分我还没有深入)。使用微库而不使用系统库在程序连接时,不会把包含printf函数的库连接到终极目标文件中,而使用我们定义的库。启动时需要完成的工作就是之前论述的步骤相比使用系统库,启动过程步骤更少。
6.总结
启动文件XXX.s从头开始执行,(C语言上分为栈、堆、.bss、.data、.code段)依次定义了栈,堆,代码段|.text|,初始化向量表后又初始化了系统的时钟的及C函数的跳转,其中__main 是一个标准的C 库函数,主要作用是初始化用户堆栈(初始化数据段在.data段,未初始化数据段在.bss数据段上)最终调用main 函数。还需要清楚的一点是假设STM32被设置为从内部FLASH启动中断向量表起始地位为0x8000000; 则栈顶地址存放于0x8000000处,而复位中断服务入口地址存放于0x8000004处。当STM32到复位信号后,则从0x80000004处取出复位中断服务入口地址继而执行复位中断服务程序,; 然后跳转__main函数最后在——main()函数的引导下进入C语言的用户main()函数开始执行。