circuitpython/ports/stm32/resethandler.s

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2018 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
.syntax unified
.cpu cortex-m4
.thumb
.section .text.Reset_Handler
.global Reset_Handler
.type Reset_Handler, %function
Reset_Handler:
/* Save the first argument to pass through to stm32_main */
mov r4, r0
/* Load the stack pointer */
ldr sp, =_estack
/* Initialise the data section */
ldr r1, =_sidata
ldr r2, =_sdata
ldr r3, =_edata
b .data_copy_entry
.data_copy_loop:
ldr r0, [r1], #4 /* Should be 4-aligned to be as fast as possible */
str r0, [r2], #4
.data_copy_entry:
cmp r2, r3
bcc .data_copy_loop
/* Zero out the BSS section */
movs r0, #0
ldr r1, =_sbss
ldr r2, =_ebss
b .bss_zero_entry
.bss_zero_loop:
str r0, [r1], #4 /* Should be 4-aligned to be as fast as possible */
.bss_zero_entry:
cmp r1, r2
bcc .bss_zero_loop
/* Jump to the main code */
mov r0, r4
b stm32_main
.size Reset_Handler, .-Reset_Handler