rt-thread/bsp/stm32f10x-HAL/drivers/gcc_startup.s

/**
  *************** (C) COPYRIGHT 2017 STMicroelectronics ************************
  * @file      gcc_startup.s
  * @author    MCD Application Team
  * @version   V4.2.0
  * @date      31-March-2017
  * @brief     Based on STM32F103xE's startup file.
  *            This module performs:
  *                - Set the initial SP
  *                - Set the initial PC == Reset_Handler,
  *                - Set the vector table entries with the exceptions ISR address
  *                - Configure the clock system
  *                - Configure external SRAM mounted on STM3210E-EVAL board
  *                  to be used as data memory (optional, to be enabled by user)
  *                - Branches to entry in the C library (which eventually
  *                  calls main(), but entry() in RT-Thread).
  *            After Reset the Cortex-M3 processor is in Thread mode,
  *            priority is Privileged, and the Stack is set to Main.
  ******************************************************************************
  *
  * <h2><center>&copy; COPYRIGHT(c) 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.
  *
  ******************************************************************************
  */

  .syntax unified
  .cpu cortex-m3
  .fpu softvfp
  .thumb

/**
 * @brief  This is the code that gets called when the processor first
 *          starts execution following a reset event. Only the absolutely
 *          necessary set is performed, after which the application
 *          supplied main() routine is called.
 * @param  None
 * @retval : None
*/

  .global Reset_Handler

  .section .text.Reset_Handler
  .type Reset_Handler, %function
Reset_Handler:

/* Copy the data segment initializers from flash to SRAM */
  movs r1, #0
  b LoopCopyDataInit

CopyDataInit:
  ldr r3, =_sidata
  ldr r3, [r3, r1]
  str r3, [r0, r1]
  adds r1, r1, #4

LoopCopyDataInit:
  ldr r0, =_sdata
  ldr r3, =_edata
  adds r2, r0, r1
  cmp r2, r3
  bcc CopyDataInit
  ldr r2, =_sbss
  b LoopFillZerobss
/* Zero fill the bss segment. */
FillZerobss:
  movs r3, #0
  str r3, [r2], #4

LoopFillZerobss:
  ldr r3, = _ebss
  cmp r2, r3
  bcc FillZerobss

/* Call the clock system intitialization function.*/
  bl  SystemInit
/* Call static constructors */
  bl __libc_init_array
/* Call the application's entry point.*/
  bl entry
  bx lr
.size Reset_Handler, .-Reset_Handler