(1)按启动代码的次序,先看堆和栈的初始化:
Stack_Size EQU 0x00000200 ;定义Stack_Size为0x00000200
AREA STACK, NOINIT, READWRITE, ALIGN=3 ;定义栈,可初始为0,8字节对齐
Stack_Mem SPACE Stack_Size ;分配0x200个连续字节,并初始化为0
__initial_sp ;汇编代码地址标号
Heap_Size EQU 0x00000000
AREA HEAP, NOINIT, READWRITE, ALIGN=3
__heap_base
Heap_Mem SPACE Heap_Size
__heap_limit
PRESERVE8 ;指定当前文件堆栈8字节对齐
THUMB ;告诉汇编器下面是32为的Thumb指令,如果需要汇编器将插入位以保证对齐
(2)中断向量表定义
AREA RESET, DATA, READONLY ;定义复位向量段,只读
EXPORT __Vectors ;定义一个可以在其他文件中使用的全局标号。此处表示中断地址
__Vectors DCD __initial_sp ; 给__initial_sp分配4字节32位的地址0x0
DCD Reset_Handler ; 给标号Reset Handler分配地址为0x00000004
DCD NMI_Handler ; 给标号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 ; 这种形式就是保留地址,不给任何标号分配
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 DMAChannel1_IRQHandler ; DMA Channel 1
DCD DMAChannel2_IRQHandler ; DMA Channel 2
DCD DMAChannel3_IRQHandler ; DMA Channel 3
DCD DMAChannel4_IRQHandler ; DMA Channel 4
DCD DMAChannel5_IRQHandler ; DMA Channel 5
DCD DMAChannel6_IRQHandler ; DMA Channel 6
DCD DMAChannel7_IRQHandler ; DMA Channel 7
DCD ADC_IRQHandler ; ADC
DCD USB_HP_CAN_TX_IRQHandler ; USB High Priority or CAN TX
DCD USB_LP_CAN_RX0_IRQHandler ; USB Low Priority or CAN RX0
DCD CAN_RX1_IRQHandler ; CAN RX1
DCD CAN_SCE_IRQHandler ; CAN 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
(3)中断向量表的转移
AREA |.text|, CODE, READONLY ;代码段定义
; Reset Handler
Reset_Handler PROC ;标记一个函数的开始
EXPORT Reset_Handler
[WEAK];[WEAK] 选项表示当所有的源文件都没有 定义这样一个标号时,编译器也不给出错误信息,在多数情况下将该标号置为 0
,若该标号为 B 或 BL 指令引用,则将 B 或 BL指令置为 NOP 操作。EXPORT提示编译器该标号可以为外部文件引用。
IMPORT __main ;通知编译器要使用的标号在其他文件
LDR R0, =__main;使用“=”表示LDR目前是伪指令不是标准指令。这里是把__main的地址给RO。
BX R0;BX是ARM指令集和THUMB指令集之间程序的跳转
ENDP
; Dummy Exception Handlers (infinite loops which can be modified)
NMI_Handler m ;"m"其实就是PROC表示汇编函数的开始
EXPORT NMI_Handler [WEAK]
B .
ENDP
HardFault_Handler\ ;"\"是换行的意思
PROC
EXPORT HardFault_Handler [WEAK]
B . ;"."号到底是什么含义呢,目前还没查到资料。可能是保留地址,供以后修改的吧
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 DMAChannel1_IRQHandler [WEAK]
EXPORT DMAChannel2_IRQHandler [WEAK]
EXPORT DMAChannel3_IRQHandler [WEAK]
EXPORT DMAChannel4_IRQHandler [WEAK]
EXPORT DMAChannel5_IRQHandler [WEAK]
EXPORT DMAChannel6_IRQHandler [WEAK]
EXPORT DMAChannel7_IRQHandler [WEAK]
EXPORT ADC_IRQHandler [WEAK]
EXPORT USB_HP_CAN_TX_IRQHandler [WEAK]
EXPORT USB_LP_CAN_RX0_IRQHandler [WEAK]
EXPORT CAN_RX1_IRQHandler [WEAK]
EXPORT CAN_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]
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