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RISC-V MCU启动文件分析

作者:互联网

启动文件由汇编语言编写,是MCU上电复位后第一个执行的程序。主要执行以下内容:

CH32V103启动文件如下:

/********************************** (C) COPYRIGHT *******************************
* File Name          : startup_ch32v10x.s
* Author             : WCH
* Version            : V1.0.0
* Date               : 2020/04/30
* Description        : CH32V10x vector table for eclipse toolchain.
*******************************************************************************/
 
    .section    .init,"ax",@progbits     /* 声明section 为 .init */
    .global    _start                       /* 指明标签_start的属性为全局性的 */
    .align    1
_start:                                  /* 标签_start处 */
    j    handle_reset                     /* 跳转至 handle_reset处 */
    .word 0x00000013                     /* 内核设计需要,不用关注 */
    .word 0x00000013
    .word 0x00000013
    .word 0x00000013
    .word 0x00000013
    .word 0x00000013
    .word 0x00000013
    .word 0x00000013
    .word 0x00000013
    .word 0x00000013
    .word 0x00000013
    .word 0x00000013
    .word 0x00100073
    .section    .vector,"ax",@progbits
    .align  1
_vector_base:                           /* 中断向量表  */
    .option norvc;
        j   _start
    .word   0
        j   NMI_Handler                 /* NMI Handler */
        j   HardFault_Handler           /* Hard Fault Handler */
    .word   0
    .word   0
    .word   0
    .word   0
    .word   0
    .word   0
    .word   0
    .word   0
        j   SysTick_Handler            /* SysTick Handler */
    .word   0
        j   SW_handler                 /* SW Handler */
    .word   0
    /* External Interrupts */
        j   WWDG_IRQHandler            /* Window Watchdog */
        j   PVD_IRQHandler             /* PVD through EXTI Line detect */
        j   TAMPER_IRQHandler          /* TAMPER */
        j   RTC_IRQHandler             /* RTC */
        j   FLASH_IRQHandler           /* Flash */
        j   RCC_IRQHandler             /* RCC */
        j   EXTI0_IRQHandler           /* EXTI Line 0 */
        j   EXTI1_IRQHandler           /* EXTI Line 1 */
        j   EXTI2_IRQHandler           /* EXTI Line 2 */
        j   EXTI3_IRQHandler           /* EXTI Line 3 */
        j   EXTI4_IRQHandler           /* EXTI Line 4 */
        j   DMA1_Channel1_IRQHandler   /* DMA1 Channel 1 */
        j   DMA1_Channel2_IRQHandler   /* DMA1 Channel 2 */
        j   DMA1_Channel3_IRQHandler   /* DMA1 Channel 3 */
        j   DMA1_Channel4_IRQHandler   /* DMA1 Channel 4 */
        j   DMA1_Channel5_IRQHandler   /* DMA1 Channel 5 */
        j   DMA1_Channel6_IRQHandler   /* DMA1 Channel 6 */
        j   DMA1_Channel7_IRQHandler   /* DMA1 Channel 7 */
        j   ADC1_2_IRQHandler          /* ADC1_2 */
        .word   0
        .word   0
        .word   0
        .word   0
        j   EXTI9_5_IRQHandler         /* EXTI Line 9..5 */
        j   TIM1_BRK_IRQHandler        /* TIM1 Break */
        j   TIM1_UP_IRQHandler         /* TIM1 Update */
        j   TIM1_TRG_COM_IRQHandler    /* TIM1 Trigger and Commutation */
        j   TIM1_CC_IRQHandler         /* TIM1 Capture Compare */
        j   TIM2_IRQHandler            /* TIM2 */
        j   TIM3_IRQHandler            /* TIM3 */
        j   TIM4_IRQHandler            /* TIM4 */
        j   I2C1_EV_IRQHandler         /* I2C1 Event */
        j   I2C1_ER_IRQHandler         /* I2C1 Error */
        j   I2C2_EV_IRQHandler         /* I2C2 Event */
        j   I2C2_ER_IRQHandler         /* I2C2 Error */
        j   SPI1_IRQHandler            /* SPI1 */
        j   SPI2_IRQHandler            /* SPI2 */
        j   USART1_IRQHandler          /* USART1 */
        j   USART2_IRQHandler          /* USART2 */
        j   USART3_IRQHandler          /* USART3 */
        j   EXTI15_10_IRQHandler       /* EXTI Line 15..10 */
        j   RTCAlarm_IRQHandler        /* RTC Alarm through EXTI Line */
        j   USBWakeUp_IRQHandler       /* USB Wakeup from suspend */
        j   USBHD_IRQHandler           /* USBHD */
 
    .option rvc;
 
    .section    .text.  , "ax", @progbits     /* 中断服务程序弱定义  */
    .weak   NMI_Handler
    .weak   HardFault_Handler
    .weak   SysTick_Handler
    .weak   SW_handler
    .weak   WWDG_IRQHandler
    .weak   PVD_IRQHandler
    .weak   TAMPER_IRQHandler
    .weak   RTC_IRQHandler
    .weak   FLASH_IRQHandler
    .weak   RCC_IRQHandler
    .weak   EXTI0_IRQHandler
    .weak   EXTI1_IRQHandler
    .weak   EXTI2_IRQHandler
    .weak   EXTI3_IRQHandler
    .weak   EXTI4_IRQHandler
    .weak   DMA1_Channel1_IRQHandler
    .weak   DMA1_Channel2_IRQHandler
    .weak   DMA1_Channel3_IRQHandler
    .weak   DMA1_Channel4_IRQHandler
    .weak   DMA1_Channel5_IRQHandler
    .weak   DMA1_Channel6_IRQHandler
    .weak   DMA1_Channel7_IRQHandler
    .weak   ADC1_2_IRQHandler
    .weak   EXTI9_5_IRQHandler
    .weak   TIM1_BRK_IRQHandler
    .weak   TIM1_UP_IRQHandler
    .weak   TIM1_TRG_COM_IRQHandler
    .weak   TIM1_CC_IRQHandler
    .weak   TIM2_IRQHandler
    .weak   TIM3_IRQHandler
    .weak   TIM4_IRQHandler
    .weak   I2C1_EV_IRQHandler
    .weak   I2C1_ER_IRQHandler
    .weak   I2C2_EV_IRQHandler
    .weak   I2C2_ER_IRQHandler
    .weak   SPI1_IRQHandler
    .weak   SPI2_IRQHandler
    .weak   USART1_IRQHandler
    .weak   USART2_IRQHandler
    .weak   USART3_IRQHandler
    .weak   EXTI15_10_IRQHandler
    .weak   RTCAlarm_IRQHandler
    .weak   USBWakeUp_IRQHandler
    .weak   USBHD_IRQHandler
 
    .section    .text.handle_reset,"ax",@progbits
    .weak    handle_reset
    .align    1
handle_reset:                     /*  handle_reset起始位置 */
.option push 
.option    norelax 
    la gp, __global_pointer$       /* 将ld文件中的标签__global_pointer所处的地址值赋给gp寄存器 */
.option    pop 
1:
    la sp, _eusrstack              /* 将ld文件中的标签_eusrstack所处的地址值赋给sp寄存器 */
2:
    /* Load data section from flash to RAM */
    la a0, _data_lma
    la a1, _data_vma
    la a2, _edata
    bgeu a1, a2, 2f
1:
    lw t0, (a0)
    sw t0, (a1)
    addi a0, a0, 4
    addi a1, a1, 4
    bltu a1, a2, 1b
2:
    /* clear bss section */
    la a0, _sbss
    la a1, _ebss
    bgeu a0, a1, 2f
1:
    sw zero, (a0)
    addi a0, a0, 4
    bltu a0, a1, 1b
2:
    /* enable all interrupt */  /* csrs ,根据寄存器中每个为1的位,把CSR寄存器对应位置位 */
  li t0, 0x88
  csrs mstatus, t0         /* 状态寄存器mstatus赋值为0x88,打开所有中断,设置MPP值为00 */
    la t0, _vector_base
  ori t0, t0, 1
    csrw mtvec, t0         /* 将中断向量表的首地址赋值给mtvec寄存器(中断发生时PC的地址) */
 
  jal  SystemInit          /* 设置MCU系统时钟 */
    la t0, main
    csrw mepc, t0  
    mret
 
/*
mret返回指令(M模式特有的指令),调用该指令会进行如下操作:
 
- 将PC指针设置为mepc的值
- 将mstatus的MPIE域复制到MIE来恢复之前的中断使能
- 将权限模式设置为mstatus的MPP域中的值。
 
芯片上电默认进入的是机器模式,通过将mstatus中的MPP值设置为00(00: User, 01: Supervisor, 11: Machine),
并将main函数的地址赋值给mepc,调用mret,使得用户在进入main函数运行时,芯片由机器模式切换为用户模式。
*/

 

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标签:0x00000013,TIM1,word,启动,weak,RISC,IRQHandler,DMA1,MCU
来源: https://www.cnblogs.com/zxyy-/p/16373322.html