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STM32_startup文件详解

article 2024/11/14 1:59:53

一、堆栈内存分配

Stack_Size EQU 0x00000400

AREA STACK, NOINIT, READWRITE, ALIGN=3
Stack_Mem SPACE Stack_Size
__initial_sp

; <h> Heap Configuration
; <o> Heap Size (in Bytes) <0x0-0xFFFFFFFF:8>
; </h>

Heap_Size EQU 0x00000200

AREA HEAP, NOINIT, READWRITE, ALIGN=3;ALLGIN代表的是该内存的起始地址对其了2的3次方的边界
__heap_base
Heap_Mem SPACE Heap_Size;space代表的是分配内存，这个heap_size是EQU定义的常量
__heap_limit

上述汇编代码主要是对堆和栈的内存进行分配。

二、中断向量表映射

; 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 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_2
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
__Vectors_End

__Vectors_Size EQU __Vectors_End - __Vectors

AREA |.text|, CODE, READONLY

三、复位中断函数

; Reset handler
Reset_Handler PROC;PROC代表函数的开始
EXPORT Reset_Handler [WEAK];EXPORT表示导出，可以被其他文件引用，import代表引入，weak代表弱符号，如果其他地方定义了同名函数，就会覆盖此函数
IMPORT __main;程序入口，负责c语言环境设置，初始化全局变量等，并且调用main函数
IMPORT SystemInit;系统时钟初始化
LDR R0, =SystemInit
BLX R0;BLX是B和LR的结合，所以跳转后返回，返回到下一条指令，这里代表先跳转去初始化时钟
LDR R0, =__main;这里就返回回来了，装入程序入口点
BX R0;没有L所以是直接跳转不返回，表示进入main函数不返回，这里的x代表的是exchange模式，如果R0的地址最低为0，切换到ARM，1切换到Thumb
ENDP;结束标志

上述代码是复位中断函数内容，这个函数是程序启动的关键。我们知道程序启动流程是，进行堆栈初始化之后，复位或者上电触发复位中断，在中断里边执行了系统时钟的初始化函数，就会去调用main函数，从而进入main函数执行。其中_main函数主要负责c语言环境设置，包括初始化全局变量等，然后调用main函数，并且处理main函数的返回值。

三、堆栈初始化

IF :DEF:__MICROLIB

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

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