xiuos3/arch/arm/cortex-m4/boot.S

110 lines
3.6 KiB
ArmAsm

/**
******************************************************************************
* @file startup_stm32f407xx.s
* @author MCD Application Team
* @brief STM32F407xx Devices vector table for GCC based toolchains.
* This module performs:
* - Set the initial SP
* - Set the initial PC == Reset_Handler,
* - Set the vector table entries with the exceptions ISR address
* - Branches to main in the C library (which eventually
* calls main()).
* After Reset the Cortex-M4 processor is in Thread mode,
* priority is Privileged, and the Stack is set to Main.
******************************************************************************
* @attention
*
* <h2><center>&copy; COPYRIGHT 2017 STMicroelectronics</center></h2>
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of STMicroelectronics nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
*/
/**
* @file boot.S
* @brief derived from ST standard peripheral library
* @version 1.0
* @author AIIT XUOS Lab
* @date 2021-04-25
*/
/*************************************************
File name: boot.S
Description: Reset and init function
Others:
History:
1. Date: 2021-04-29
Author: AIIT XUOS Lab
Modification:
1. take startup_stm32f407xx.s for XiUOS
*************************************************/
.syntax unified
.cpu cortex-m4
.fpu softvfp
.thumb
.word _sidata
.word _sdata
.word _edata
.word __bss_start
.word __bss_end
.section .text.Reset_Handler
.weak Reset_Handler
.type Reset_Handler, %function
Reset_Handler:
ldr sp, =__stack_tp
movs r1, #0
/* Copy the data segment initializers from flash to SRAM */
DataInit:
ldr r0, =_sdata
ldr r3, =_edata
adds r2, r0, r1
cmp r2, r3
bcs DataInitEnd
ldr r3, =_sidata
ldr r3, [r3, r1]
str r3, [r0, r1]
adds r1, r1, #4
b DataInit
DataInitEnd:
ldr r2, =__bss_start
/* Zero fill the bss segment. */
BSSInit:
ldr r3, = __bss_end
cmp r2, r3
bcs BSSInitEnd
movs r3, #0
str r3, [r2], #4
b BSSInit
BSSInitEnd:
bl SystemInit
bl stm32f407_start
bx lr
.size Reset_Handler, .-Reset_Handler