81 lines
2.8 KiB
C
81 lines
2.8 KiB
C
/**
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******************************************************************************
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* @file sysmem.c
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* @author Generated by STM32CubeIDE
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* @brief STM32CubeIDE System Memory calls file
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*
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* For more information about which C functions
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* need which of these lowlevel functions
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* please consult the newlib libc manual
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******************************************************************************
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* @attention
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*
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* <h2><center>© Copyright (c) 2020 STMicroelectronics.
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* All rights reserved.</center></h2>
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*
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* This software component is licensed by ST under BSD 3-Clause license,
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* the "License"; You may not use this file except in compliance with the
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* License. You may obtain a copy of the License at:
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* opensource.org/licenses/BSD-3-Clause
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*
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******************************************************************************
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*/
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/* Includes */
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#include <errno.h>
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#include <stdint.h>
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/**
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* Pointer to the current high watermark of the heap usage
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*/
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static uint8_t *__sbrk_heap_end = NULL;
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/**
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* @brief _sbrk() allocates memory to the newlib heap and is used by malloc
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* and others from the C library
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*
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* @verbatim
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* ############################################################################
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* # .data # .bss # newlib heap # MSP stack #
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* # # # # Reserved by _Min_Stack_Size #
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* ############################################################################
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* ^-- RAM start ^-- _end _estack, RAM end --^
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* @endverbatim
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*
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* This implementation starts allocating at the '_end' linker symbol
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* The '_Min_Stack_Size' linker symbol reserves a memory for the MSP stack
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* The implementation considers '_estack' linker symbol to be RAM end
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* NOTE: If the MSP stack, at any point during execution, grows larger than the
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* reserved size, please increase the '_Min_Stack_Size'.
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*
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* @param incr Memory size
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* @return Pointer to allocated memory
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*/
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void *_sbrk(ptrdiff_t incr)
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{
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extern uint8_t _end; /* Symbol defined in the linker script */
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extern uint8_t _estack; /* Symbol defined in the linker script */
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extern uint32_t _Min_Stack_Size; /* Symbol defined in the linker script */
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const uint32_t stack_limit = (uint32_t)&_estack - (uint32_t)&_Min_Stack_Size;
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const uint8_t *max_heap = (uint8_t *)stack_limit;
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uint8_t *prev_heap_end;
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/* Initalize heap end at first call */
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if (NULL == __sbrk_heap_end)
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{
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__sbrk_heap_end = &_end;
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}
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/* Protect heap from growing into the reserved MSP stack */
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if (__sbrk_heap_end + incr > max_heap)
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{
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errno = ENOMEM;
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return (void *)-1;
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}
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prev_heap_end = __sbrk_heap_end;
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__sbrk_heap_end += incr;
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return (void *)prev_heap_end;
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}
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