STM32 & ARM汇编启动程序
1、STM32启动汇编文件
下面是startup_stm32f10x_hd.s汇编文件代码:
Stack_Size EQU 0x00000400 ;先定义Stack_Size大小为0x00000400
AREA STACK, NOINIT, READWRITE, ALIGN=3
;定义栈,未初始化,可读可写,堆数据段8字节边界对齐
Stack_Mem SPACE Stack_Size ;分配空间大小为Stack_Size (0x00000400)
__initial_sp
;
Heap Configuration
; Heap Size (in Bytes) <0x0-0xFFFFFFFF:8>
;
Heap_Size EQU 0x00000200
;定义堆,未初始化,可读可写,。。
AREA HEAP, NOINIT, READWRITE, ALIGN=3
__heap_base
Heap_Mem SPACE Heap_Size
__heap_limit
PRESERVE8 ;命令指定当前文件保持栈的八字节对齐
THUMB ; THUMB指令集必须位于使用新语法的任何Thumb代码之前
;向量表映射地址
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
; 外部中断
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 ;计算向量表地址空间大小
;定义区域代码名|.text|,代码段,只读
AREA |.text|, CODE, READONLY
; Reset handler
Reset_Handler PROC
EXPORT Reset_Handler [WEAK]
;此处[WEAK]表示弱定义,优先执行其他文件的定义
IMPORT __main
IMPORT SystemInit
LDR R0, =SystemInit
BLX R0
LDR R0, =__main
BX R0
ENDP
; Dummy Exception Handlers (infinite loops which can be modified)
NMI_Handler PROC
EXPORT NMI_Handler [WEAK]
B .
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
; 输出异常向量表标号,方便外部实现异常的具体功能,[WEAK]是弱定义的意思,如果外部定义了,优先执行外部定义,否则下面的函数定义
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]
; 如下只是定义一个空函数
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 ; 默认是字对齐方式,也说明了代码是4字节对齐的
;******************************************************************************
; User Stack and Heap initialization
;******************************************************************************
IF :DEF:__MICROLIB ;如果勾选了MicroLib就执行下面
EXPORT __initial_sp
EXPORT __heap_base
EXPORT __heap_limit
ELSE ;没勾选就使用下面
IMPORT __use_two_region_memory
EXPORT __user_initial_stackheap
__user_initial_stackheap
;此处是初始化两区的堆栈空间,堆是从由低到高的增长,栈是由高向低生长的,两个是互相独立的数据段,并不能交叉使用。
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 ;文件末尾处
以上代码注释仅供参考
[tr]符号寄存器名称[/tr]
R0~R12 | 通用寄存器 |
R13(LR) | 链接寄存器 |
P14(PC) | 程序计数器 |
2、C语言内嵌汇编
根据软件仿真的汇编指令与C语言配合,应该可以提升代码执行效率,但是带来的后果是不利于观察他们的逻辑,所以不建议全部都用汇编。一部分代码使用汇编就好。
- 【1】先举个栗子
我先定义一个无返回值,无形参输入的函数。
void add(){
int i, int j
int res;
return res;
}
//主函数里面,就不放死循环了
int main(){
//内嵌汇编,使用BL命令然后,填写标签(C语言叫函数名称),多指令写法如下
__ASM{
BL add
}
//另一种写法
__asm("BL add");//跳转到add函数
}
【2】内联汇编不能对物理寄存器直接操作。。。我试过多次还是不行,会被编译器优化处理成 NOP指令(这个指令什么也不做)。。。也就是说什么也不干。
然后尝试了一下,下面这种方法,据说也能写汇编
#pragma asm
//汇编指令写在这里
#pragma endasm
但这种方法只适合用于51单片机的汇编,不适用于ARM。如果在ARM KEIL开发环境会报错说 “ pragma不认识 ”。
【3】另一种汇编,可以在函数里面直接写汇编代码
__asm void add(void){
//此处编写汇编指令
}
3、子程序执行
下面是通过KEIL5软件仿真得到的结果。
①执行代码
IMPORT SystemInit
;在开头时候已经声明SystemInit,不然编译器懵逼往不知道哪里找这个地址。
LDR R0 , =SystemInit ;加载SystemInit地址到R0寄存器
BLX R0 ;跳转到R0地址
运行上面几行代码会跳转到SystemInit( )函数并且执行,此时寄存器数值如下:
[tr]LRPC[/tr]
②进入子程序SystemInit()后,首先执行代码如下
PUSH { R4 , LR } ;R4和LR寄存器压入栈 寄存器数值如下:
[tr]LRPC[/tr]
运行子程序SystemInit退出前,会先出行出栈执行指令跳回原来汇编文件,就是下面指令
POP { R4 , PC } ;R4和LR寄存器出栈,执行完之后就会跳到0x08005844地址继续执行
当进入子程序之后,第一条指令是LR寄存器数值先入栈,运行完子程序退出时候这个数值会出栈交给PC寄存器,从而实现退出子程序。
栈特点是先进后出,而且根据程序入栈与出栈是平衡的,当汇编语言进入C语言函数后:
先执行PUSH { R4 , LR } ,
再次新的子程序后将寄存器数据压入栈中PUSH { R4 , LR },
再次有新的子程序进入后,寄存器将数据压入堆栈中PUSH { R2-R3 , LR }
返回原来程序前出栈先POP { R2 - R3 , PC },
跳出当前子程序后再次出栈POP { R4 , PC },
再次出栈指令POP { R4 , PC }
总结:
- 进入子程序后,执行指令出栈与入栈是平衡的,保证程序执行不混乱:
当执行PUSH { R4 , LR } ,必有POP { R4 , PC }
当执行PUSH { R2-R3 , LR } ,必有POP { R2-R3 , PC }
- LR入栈后,出栈后交给PC寄存器。PC寄存器得到数值后,他会找到一条小于这个数值(这个数值就是程序执行的地址)的汇编指令然后继续执行。
STM32 & ARM汇编启动程序
1、STM32启动汇编文件
下面是startup_stm32f10x_hd.s汇编文件代码:
Stack_Size EQU 0x00000400 ;先定义Stack_Size大小为0x00000400
AREA STACK, NOINIT, READWRITE, ALIGN=3
;定义栈,未初始化,可读可写,堆数据段8字节边界对齐
Stack_Mem SPACE Stack_Size ;分配空间大小为Stack_Size (0x00000400)
__initial_sp
;
Heap Configuration
; Heap Size (in Bytes) <0x0-0xFFFFFFFF:8>
;
Heap_Size EQU 0x00000200
;定义堆,未初始化,可读可写,。。
AREA HEAP, NOINIT, READWRITE, ALIGN=3
__heap_base
Heap_Mem SPACE Heap_Size
__heap_limit
PRESERVE8 ;命令指定当前文件保持栈的八字节对齐
THUMB ; THUMB指令集必须位于使用新语法的任何Thumb代码之前
;向量表映射地址
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
; 外部中断
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 ;计算向量表地址空间大小
;定义区域代码名|.text|,代码段,只读
AREA |.text|, CODE, READONLY
; Reset handler
Reset_Handler PROC
EXPORT Reset_Handler [WEAK]
;此处[WEAK]表示弱定义,优先执行其他文件的定义
IMPORT __main
IMPORT SystemInit
LDR R0, =SystemInit
BLX R0
LDR R0, =__main
BX R0
ENDP
; Dummy Exception Handlers (infinite loops which can be modified)
NMI_Handler PROC
EXPORT NMI_Handler [WEAK]
B .
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
; 输出异常向量表标号,方便外部实现异常的具体功能,[WEAK]是弱定义的意思,如果外部定义了,优先执行外部定义,否则下面的函数定义
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]
; 如下只是定义一个空函数
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 ; 默认是字对齐方式,也说明了代码是4字节对齐的
;******************************************************************************
; User Stack and Heap initialization
;******************************************************************************
IF :DEF:__MICROLIB ;如果勾选了MicroLib就执行下面
EXPORT __initial_sp
EXPORT __heap_base
EXPORT __heap_limit
ELSE ;没勾选就使用下面
IMPORT __use_two_region_memory
EXPORT __user_initial_stackheap
__user_initial_stackheap
;此处是初始化两区的堆栈空间,堆是从由低到高的增长,栈是由高向低生长的,两个是互相独立的数据段,并不能交叉使用。
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 ;文件末尾处
以上代码注释仅供参考
[tr]符号寄存器名称[/tr]
R0~R12 | 通用寄存器 |
R13(LR) | 链接寄存器 |
P14(PC) | 程序计数器 |
2、C语言内嵌汇编
根据软件仿真的汇编指令与C语言配合,应该可以提升代码执行效率,但是带来的后果是不利于观察他们的逻辑,所以不建议全部都用汇编。一部分代码使用汇编就好。
- 【1】先举个栗子
我先定义一个无返回值,无形参输入的函数。
void add(){
int i, int j
int res;
return res;
}
//主函数里面,就不放死循环了
int main(){
//内嵌汇编,使用BL命令然后,填写标签(C语言叫函数名称),多指令写法如下
__ASM{
BL add
}
//另一种写法
__asm("BL add");//跳转到add函数
}
【2】内联汇编不能对物理寄存器直接操作。。。我试过多次还是不行,会被编译器优化处理成 NOP指令(这个指令什么也不做)。。。也就是说什么也不干。
然后尝试了一下,下面这种方法,据说也能写汇编
#pragma asm
//汇编指令写在这里
#pragma endasm
但这种方法只适合用于51单片机的汇编,不适用于ARM。如果在ARM KEIL开发环境会报错说 “ pragma不认识 ”。
【3】另一种汇编,可以在函数里面直接写汇编代码
__asm void add(void){
//此处编写汇编指令
}
3、子程序执行
下面是通过KEIL5软件仿真得到的结果。
①执行代码
IMPORT SystemInit
;在开头时候已经声明SystemInit,不然编译器懵逼往不知道哪里找这个地址。
LDR R0 , =SystemInit ;加载SystemInit地址到R0寄存器
BLX R0 ;跳转到R0地址
运行上面几行代码会跳转到SystemInit( )函数并且执行,此时寄存器数值如下:
[tr]LRPC[/tr]
②进入子程序SystemInit()后,首先执行代码如下
PUSH { R4 , LR } ;R4和LR寄存器压入栈 寄存器数值如下:
[tr]LRPC[/tr]
运行子程序SystemInit退出前,会先出行出栈执行指令跳回原来汇编文件,就是下面指令
POP { R4 , PC } ;R4和LR寄存器出栈,执行完之后就会跳到0x08005844地址继续执行
当进入子程序之后,第一条指令是LR寄存器数值先入栈,运行完子程序退出时候这个数值会出栈交给PC寄存器,从而实现退出子程序。
栈特点是先进后出,而且根据程序入栈与出栈是平衡的,当汇编语言进入C语言函数后:
先执行PUSH { R4 , LR } ,
再次新的子程序后将寄存器数据压入栈中PUSH { R4 , LR },
再次有新的子程序进入后,寄存器将数据压入堆栈中PUSH { R2-R3 , LR }
返回原来程序前出栈先POP { R2 - R3 , PC },
跳出当前子程序后再次出栈POP { R4 , PC },
再次出栈指令POP { R4 , PC }
总结:
- 进入子程序后,执行指令出栈与入栈是平衡的,保证程序执行不混乱:
当执行PUSH { R4 , LR } ,必有POP { R4 , PC }
当执行PUSH { R2-R3 , LR } ,必有POP { R2-R3 , PC }
- LR入栈后,出栈后交给PC寄存器。PC寄存器得到数值后,他会找到一条小于这个数值(这个数值就是程序执行的地址)的汇编指令然后继续执行。
举报