STM32啓動文件詳解

;先在RAM中分配系統使用的棧,RAM的起始地址爲0x2000_0000
;然後在RAM中分配變量使用的堆
;然後在CODE區(flash)分配中斷向量表,flash的起始地址爲0x0800_0000,該中斷向量表就從這個起始地址開始分配
;分配完成後,再定義和實現相應的中斷函數,
;所有的中斷函數全部帶有[weak]特性,即弱定義,如果編譯器發現在別處文件中定義了同名函數,在鏈接時用別處的地址進行鏈接。
;中斷函數僅僅實現了Reset_Handler,其他要麼是死循環,要麼僅僅定義了函數名稱

;STM32被設置爲從內部FLASH啓動時(這也是最常見的一種情況),當STM32遇到復位信號後,
;從0x0800_0000處取出棧頂地址存放於MSP寄存器,從0x0800_0004處取出復位中斷服務入口地址放入PC寄存器,
;繼而執行復位中斷服務程序Reset_Handler,
;Reset_Handler僅僅執行了兩個函數調用,一個是SystemInit,另一個__main,
;SystemInit定義在system_stm32f10x.c中,主要初始化了STM的時鐘系統:HSI,HSE,LSI,LSE,PLL,SYSCLK,USBCLK,APECLK等等.
;__main函數由編譯器生成,負責初始化棧、堆等,並在最後跳轉到用戶自定義的main()函數,來到C的世界。


Stack_Size      EQU     0x00000400  ;//定義堆棧大小
                AREA    STACK, NOINIT, READWRITE, ALIGN=3  ;//定義一個數據段 按8字節對齊    ;AREA 僞指令用於定義一個代碼段或數據段 NOINIT:指定此數據段僅僅保留了內存單元,而沒有將各初始值寫入內存單元,或者將各個內存單元值初始化爲0
Stack_Mem       SPACE   Stack_Size    ;//保留Stack_Size大小的堆棧空間 分 配連續 Stack_Size 字節的存儲單元並初始化爲 0
__initial_sp  ;//標號,代表堆棧頂部地址,後面有用
                                                  
; <h> Heap Configuration
;   <o>  Heap Size (in Bytes) <0x0-0xFFFFFFFF:8>
; </h>
Heap_Size       EQU     0x00000200    ;//定義堆空間大小
                AREA    HEAP, NOINIT, READWRITE, ALIGN=3  ;//定義一個數據段,8字節對齊
__heap_base      ;//標號,代表堆末底部地址,後面有用
Heap_Mem        SPACE   Heap_Size     ;//保留Heap_Size的堆空間  
__heap_limit     ;//標號,代表堆界限地址,後面有用
    ;PRESERVE8 指令指定當前文件保持堆棧八字節對齊。 它設置 PRES8 編譯屬性以通知鏈接器。
    ;鏈接器檢查要求堆棧八字節對齊的任何代碼是否僅由保持堆棧八字節對齊的代碼直接或間接地調用。
                PRESERVE8 ;//指示編譯器8字節對齊
                THUMB   ;//指示編譯器以後的指令爲THUMB指令 

;中斷向量表定義
; Vector Table Mapped to Address 0 at Reset
                AREA    RESET, DATA, READONLY   ;//定義只讀數據段,其實放在CODE區,位於0地址
                EXPORT  __Vectors    ;EXPORT:在程序中聲明一個全局的標號__Vectors,該標號可在其他的文件中引用
                EXPORT  __Vectors_End
                EXPORT  __Vectors_Size
__Vectors       DCD     __initial_sp               ; Top of Stack  ;給__initial_sp分配4字節32位的地址0x0
                DCD     Reset_Handler              ; Reset Handler ; 給標號Reset Handler分配地址爲0x00000004
                DCD     NMI_Handler                ; NMI Handler ; 給標號NMI Handler分配地址0x00000008
                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  ; 這種形式就是保留地址,不給任何標號分配
                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 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_Size  EQU  __Vectors_End - __Vectors
                AREA    |.text|, CODE, READONLY ;代碼段定義

; Reset Handler
;利用PROC、ENDP這一對僞指令把程序段分爲若干個過程,使程序的結構加清晰
Reset_Handler   PROC   ;過程的開始 
                EXPORT  Reset_Handler             [WEAK];[WEAK] 弱定義,意思是如果在別處也定義該標號(函數),在鏈接時用別處的地址。
              ;如果沒有其它定方定義,編譯器也不報錯,以此處地址進行鏈接。
              ;EXPORT提示編譯器該標號可以爲外部文件引用。
                IMPORT  __main    ;通知編譯器要使用的標號在其他文件
                IMPORT  SystemInit
                LDR     R0, =SystemInit
                BLX     R0          ;BX是ARM指令集和THUMB指令集之間程序的跳轉     
                LDR     R0, =__main ;使用“=”表示LDR目前是僞指令不是標準指令。這裏是把__main的地址給RO。
                BX      R0   ;BX是ARM指令集和THUMB指令集之間程序的跳轉
                ENDP     ;過程的結束
                
; Dummy Exception Handlers (infinite loops which can be modified)
NMI_Handler     PROC
                EXPORT  NMI_Handler                [WEAK]
                B       .      ;原地跳轉(即無限循環),
                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  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]
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 ;填充字節使地址對齊
;*******************************************************************************
; User Stack and Heap initialization
;*******************************************************************************
;堆和棧的初始化
                 IF      :DEF:__MICROLIB ;“DEF”的用法——:DEF:X 就是說X定義了則爲真,否則爲假
                       ;如果定義了MICORLIB,
                 EXPORT  __initial_sp  ;則將棧頂地址,
                 EXPORT  __heap_base  ;堆起始地址賦予全局屬性,
                 EXPORT  __heap_limit  ;堆末端界限地址賦予全局屬性,使外部程序可調用
                
                 ELSE  ;如果沒定義__MICROLIB,則使用默認的C運行時庫
                
                 IMPORT  __use_two_region_memory  ;;通知編譯器要使用的標號在其他文件__use_two_region_memory    
                 EXPORT  __user_initial_stackheap ;聲明全局標號__user_initial_stackheap,這樣外程序也可調用此標號
             ;則進行堆棧和堆的賦值,在__main函數執行過程中調用

    ;如果使用默認的C庫,程序啓動過程中就不會執行該標號下的代碼
__user_initial_stackheap     ;標號__user_initial_stackheap,表示用戶堆棧初始化程序入口
        ;//則進行堆棧和堆的賦值,在__main函數執行過程中調用。
                 LDR     R0, =  Heap_Mem     ;保存堆始地址
                 LDR     R1, =(Stack_Mem + Stack_Size) ;保存棧的大小
                 LDR     R2, = (Heap_Mem +  Heap_Size)  ;保存堆的大小
                 LDR     R3, = Stack_Mem    ;保存棧頂指針
                 BX      LR
                 ALIGN  ;填充字節使地址對齊

                 ENDIF
     
                 END

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