stm32启动代码分析

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rj2019 发布时间：2019-4-7 22:36

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启动代码在芯片上还是很重要的一部分，我们以F4的启动代码为例

下面启动代码里的汇编的注释已经去掉，添加的注释用 // 表示

/****************************************************************************/

0.分号“；”后的内容相当于C程序中的注释

1.标号的作用：标号必须顶格写，让汇编器计算程序转移的地址

2.伪指令
EQU    用于定义常数
LDR    被汇编器转换成一条“相对PC的加载指令”
BLX    转移到后面代表的地址
BX       转移到后面的地址
PROC，ENDP  表示一段程序的开始和结束

/****************************************************************************/

Stack_Size    EQU    0x00000400

            AREA STACK, NOINIT, READWRITE, ALIGN=3  //定义一段叫STACK的数据段，并初始化为0，可读可写，以8字节对齐
Stack_Mem    SPACE Stack_Size                                  //开辟一个大小为1KB（0x0000400，以字节为单位）的内存空间命名为Stack_Mem
__initial_sp //__initial_sp是一个标号，在这里相当于栈顶地址

Heap_Size    EQU    0x00000200

            AREA HEAP, NOINIT, READWRITE, ALIGN=3  //定义一段HEAP数据段，不初始化为0，可读可写，8字节对齐
__heap_base       //堆的基地址
Heap_Mem       SPACE Heap_Size //开辟一段0.5KB的空间，命名为Heap_Mem
__heap_limit       //堆的结束地址

            PRESERVE8 //表示当前文件中的堆栈空间以8字节对齐
            THUMB       //使用YHUMB指令

            AREA RESET, DATA, READONLY //开辟一段数据段，只读，命名为RESET
            EXPORT  __Vectors                //EXPORT表示可被外部调用
            EXPORT  __Vectors_End
            EXPORT  __Vectors_Size

__Vectors    DCD    __initial_sp             ; Top of Stack    //DCD表示分配一个四字节的空间
            DCD    Reset_Handler             ; Reset Handler
            DCD    NMI_Handler             ; NMI Handler
            DCD    HardFault_Handler       ; Hard Fault Handler
                           .
                           .                //中间部分省略，这一段定义的是中断向量表

                           .
            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             //向量表的大小为最后的地址减去开始的地址，为188字节

            AREA |.text|, CODE, READONLY             //定义一段代码段，只读

Reset_Handler PROC                                  //这一段定义复位中断服务函数
               EXPORT  Reset_Handler          [WEAK]    //[WEAK]为弱定义，表示如果在该文件外还有和这个相同的标号，则优先执行外部的，这样我们的中断服务函数就可以在文件中的任意位置放置
      IMPORT  SystemInit                               //IMPORT表示从外部引用 SystemInit（在system_stm32f4文件内）
      IMPORT  __main                                     //__main为C库中的函数，会完成一系列的配置，最终调用用户写的main函数

               LDR    R0, =SystemInit                //将SystemInit地址加载到R0寄存器
               BLX    R0                                     //相当于执行上面加载的函数
               LDR    R0, =__main             //将__main地址加载到R0寄存器
               BX    R0                               //执行上面加载的函数
               ENDP

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

NMI_Handler    PROC                         //NMI_Handler为不可屏蔽中断
            EXPORT  NMI_Handler             [WEAK]
            B    .                                     //如果这个中断服务函数在外部没有定义，就会进入启动文件默认的中断服务函数B . 表示死循环，
            ENDP                                     //可以用仿真器实际操作一下，下面的和这里的一样
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]

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

            B    .

            ENDP

            ALIGN

;*******************************************************************************
; User Stack and Heap initialization
;*******************************************************************************
               IF

EF:__MICROLIB          //这边判断是否使用微库

               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                   //分别将分别将栈顶地址，栈底地址，堆顶地址及堆基地址存放在寄存器R1，R3，R0，R2中。
               LDR    R1, =(Stack_Mem + Stack_Size)
               LDR    R2, = (Heap_Mem +  Heap_Size)
               LDR    R3, = Stack_Mem
               BX    LR

               ALIGN

               ENDIF

               END