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学习STM32,看了一堆乱七八糟的文档，准备写程序了，先分析了下STM32的启动代码，看着这堆鬼鬼的汇编代码，挺吓人的，看看帮助，查查网路，还是不那么难懂。
;// <h> Stack Configuration<br /> ;// <o> Stack Size (in Bytes) <0x0-0xFFFFFFFF:8><br /> ;// </h><br /> Stack_Size EQU 0x00000200 ;//定义堆栈大小<br /> AREA STACK, NOINIT, READWRITE, ALIGN=3 ;//定义一个数据段 按8字节对齐<br /> Stack_Mem SPACE Stack_Size ;//保留Stack_Size大小的堆栈空间<br /> __initial_sp ;//标号，代表堆栈顶部地址，后面有用</p> <p>;// <h> Heap Configuration<br /> ;// <o> Heap Size (in Bytes) <0x0-0xFFFFFFFF:8><br /> ;// </h><br /> Heap_Size EQU 0x00000020 ;//定义堆空间大小<br /> AREA HEAP, NOINIT, READWRITE, ALIGN=3 ;//定义一个数据段，8字节对齐<br /> __heap_base<br /> Heap_Mem SPACE Heap_Size ;//保留Heap_Size的堆空间<br /> __heap_limit ;//标号，代表堆末尾地址，后面有用</p> <p> PRESERVE8 ;//指示编译器8字节对齐<br /> THUMB ;//指示编译器为THUMB指令</p> <p>; Vector Table Mapped to Address 0 at Reset<br /> AREA RESET, DATA, READONLY ;//定义只读数据段，其实放在CODE区，位于0地址</p> <p> EXTERN NMIException<br /> EXTERN HardFaultException<br /> EXTERN MemManageException<br /> EXTERN BusFaultException<br /> EXTERN UsageFaultException<br /> EXTERN SVCHandler<br /> EXTERN DebugMonitor<br /> EXTERN PendSVC<br /> EXTERN SysTickHandler ;//声明这些符号在外部定义，同C<br /> ;//在××it.c中实现这些函数 ，中断就能自动调用了<br /> EXPORT __Vectors<br /> __Vectors DCD __initial_sp ; Top of Stack //Cotex-M 要求此处为堆栈顶部地址<br /> DCD Reset_Handler ; Reset Handler<br /> DCD NMIException ; NMI Handler<br /> DCD HardFaultException ; Hard Fault Handler<br /> DCD MemManageException ; MPU Fault Handler<br /> DCD BusFaultException ; Bus Fault Handler<br /> DCD UsageFaultException ; Usage Fault Handler<br /> DCD 0 ; Reserved<br /> DCD 0 ; Reserved<br /> DCD 0 ; Reserved<br /> DCD 0 ; Reserved<br /> DCD SVCHandler ; SVCall Handler<br /> DCD DebugMonitor ; Debug Monitor Handler<br /> DCD 0 ; Reserved<br /> DCD PendSVC ; PendSV Handler<br /> DCD SysTickHandler ; SysTick Handler //一大堆的异常处理函数地址<br /> ; External Interrupts<br /> EXTERN WWDG_IRQHandler<br /> EXTERN PVD_IRQHandler<br /> EXTERN TAMPER_IRQHandler<br /> EXTERN RTC_IRQHandler<br /> EXTERN FLASH_IRQHandler<br /> EXTERN RCC_IRQHandler<br /> EXTERN EXTI0_IRQHandler<br /> EXTERN EXTI1_IRQHandler<br /> EXTERN EXTI2_IRQHandler<br /> EXTERN EXTI3_IRQHandler<br /> EXTERN EXTI4_IRQHandler<br /> EXTERN DMAChannel1_IRQHandler<br /> EXTERN DMAChannel2_IRQHandler<br /> EXTERN DMAChannel3_IRQHandler<br /> EXTERN DMAChannel4_IRQHandler<br /> EXTERN DMAChannel5_IRQHandler<br /> EXTERN DMAChannel6_IRQHandler<br /> EXTERN DMAChannel7_IRQHandler<br /> EXTERN ADC_IRQHandler<br /> EXTERN USB_HP_CAN_TX_IRQHandler<br /> EXTERN USB_LP_CAN_RX0_IRQHandler<br /> EXTERN CAN_RX1_IRQHandler<br /> EXTERN CAN_SCE_IRQHandler<br /> EXTERN EXTI9_5_IRQHandler<br /> EXTERN TIM1_BRK_IRQHandler<br /> EXTERN TIM1_UP_IRQHandler<br /> EXTERN TIM1_TRG_COM_IRQHandler<br /> EXTERN TIM1_CC_IRQHandler<br /> EXTERN TIM2_IRQHandler<br /> EXTERN TIM3_IRQHandler<br /> EXTERN TIM4_IRQHandler<br /> EXTERN I2C1_EV_IRQHandler<br /> EXTERN I2C1_ER_IRQHandler<br /> EXTERN I2C2_EV_IRQHandler<br /> EXTERN I2C2_ER_IRQHandler<br /> EXTERN SPI1_IRQHandler<br /> EXTERN SPI2_IRQHandler<br /> EXTERN USART1_IRQHandler<br /> EXTERN USART2_IRQHandler<br /> EXTERN USART3_IRQHandler<br /> EXTERN EXTI15_10_IRQHandler<br /> EXTERN RTCAlarm_IRQHandler<br /> EXTERN USBWakeUp_IRQHandler ;//同上，</p> <p> DCD WWDG_IRQHandler ; Window Watchdog<br /> DCD PVD_IRQHandler ; PVD through EXTI Line detect<br /> DCD TAMPER_IRQHandler ; Tamper<br /> DCD RTC_IRQHandler ; RTC<br /> DCD FLASH_IRQHandler ; Flash<br /> DCD RCC_IRQHandler ; RCC<br /> DCD EXTI0_IRQHandler ; EXTI Line 0<br /> DCD EXTI1_IRQHandler ; EXTI Line 1<br /> DCD EXTI2_IRQHandler ; EXTI Line 2<br /> DCD EXTI3_IRQHandler ; EXTI Line 3<br /> DCD EXTI4_IRQHandler ; EXTI Line 4<br /> DCD DMAChannel1_IRQHandler ; DMA Channel 1<br /> DCD DMAChannel2_IRQHandler ; DMA Channel 2<br /> DCD DMAChannel3_IRQHandler ; DMA Channel 3<br /> DCD DMAChannel4_IRQHandler ; DMA Channel 4<br /> DCD DMAChannel5_IRQHandler ; DMA Channel 5<br /> DCD DMAChannel6_IRQHandler ; DMA Channel 6<br /> DCD DMAChannel7_IRQHandler ; DMA Channel 7<br /> DCD ADC_IRQHandler ; ADC<br /> DCD USB_HP_CAN_TX_IRQHandler ; USB High Priority or CAN TX<br /> DCD USB_LP_CAN_RX0_IRQHandler ; USB Low Priority or CAN RX0<br /> DCD CAN_RX1_IRQHandler ; CAN RX1<br /> DCD CAN_SCE_IRQHandler ; CAN SCE<br /> DCD EXTI9_5_IRQHandler ; EXTI Line 9..5<br /> DCD TIM1_BRK_IRQHandler ; TIM1 Break<br /> DCD TIM1_UP_IRQHandler ; TIM1 Update<br /> DCD TIM1_TRG_COM_IRQHandler ; TIM1 Trigger and Commutation<br /> DCD TIM1_CC_IRQHandler ; TIM1 Capture Compare<br /> DCD TIM2_IRQHandler ; TIM2<br /> DCD TIM3_IRQHandler ; TIM3<br /> DCD TIM4_IRQHandler ; TIM4<br /> DCD I2C1_EV_IRQHandler ; I2C1 Event<br /> DCD I2C1_ER_IRQHandler ; I2C1 Error<br /> DCD I2C2_EV_IRQHandler ; I2C2 Event<br /> DCD I2C2_ER_IRQHandler ; I2C2 Error<br /> DCD SPI1_IRQHandler ; SPI1<br /> DCD SPI2_IRQHandler ; SPI2<br /> DCD USART1_IRQHandler ; USART1<br /> DCD USART2_IRQHandler ; USART2<br /> DCD USART3_IRQHandler ; USART3<br /> DCD EXTI15_10_IRQHandler ; EXTI Line 15..10<br /> DCD RTCAlarm_IRQHandler ; RTC Alarm through EXTI Line<br /> DCD USBWakeUp_IRQHandler ; USB Wakeup from suspend ;//同上</p> <p> AREA |.text|, CODE, READONLY ;//定义代码段</p> <p>; Reset Handler<br /> Reset_Handler PROC ;//Rset_Handler的实现<br /> EXPORT Reset_Handler [WEAK] ;//在外部没有定义该符号时导出该符号，见HELP中[WEAK]<br /> IMPORT __main ;//导入符号,__main为 运行时库提供的函数；完成堆栈，堆的初始话<br /> LDR R0, =__main ;//等工作，会调用下面定义的__user_initial_stackheap；<br /> BX R0 ;//跳到__main，进入C的世界<br /> ENDP</p> <p> ALIGN</p> <p>; User Initial Stack & Heap<br /> IF :DEF:__MICROLIB ;//如果使用micro lib,micro lib 描述见armlib.chm</p> <p> EXPORT __initial_sp<br /> EXPORT __heap_base<br /> EXPORT __heap_limit ;//只导出几个定义</p> <p> ELSE ;//如果使用默认C运行时库</p> <p> IMPORT __use_two_region_memory<br /> EXPORT __user_initial_stackheap<br /> __user_initial_stackheap ;//则进行堆栈和堆的赋值，在__main函数执行过程中调用。<br /> LDR R0, = Heap_Mem<br /> LDR R1, =(Stack_Mem + Stack_Size)<br /> LDR R2, = (Heap_Mem + Heap_Size)<br /> LDR R3, = Stack_Mem<br /> BX LR<br /> ALIGN<br /> ENDIF</p> <p> END ;//OK ，完了
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