1 /** 2 ****************************************************************************** 3 * @file sysmem.c 4 * @author Generated by STM32CubeIDE 5 * @brief STM32CubeIDE System Memory calls file 6 * 7 * For more information about which C functions 8 * need which of these lowlevel functions 9 * please consult the newlib libc manual 10 ****************************************************************************** 11 * @attention 12 * 13 * Copyright (c) 2025 STMicroelectronics. 14 * All rights reserved. 15 * 16 * This software is licensed under terms that can be found in the LICENSE file 17 * in the root directory of this software component. 18 * If no LICENSE file comes with this software, it is provided AS-IS. 19 * 20 ****************************************************************************** 21 */ 22 23 /* Includes */ 24 #include <errno.h> 25 #include <stdint.h> 26 27 /** 28 * Pointer to the current high watermark of the heap usage 29 */ 30 static uint8_t *__sbrk_heap_end = NULL; 31 32 /** 33 * @brief _sbrk() allocates memory to the newlib heap and is used by malloc 34 * and others from the C library 35 * 36 * @verbatim 37 * ############################################################################ 38 * # .data # .bss # newlib heap # MSP stack # 39 * # # # # Reserved by _Min_Stack_Size # 40 * ############################################################################ 41 * ^-- RAM start ^-- _end _estack, RAM end --^ 42 * @endverbatim 43 * 44 * This implementation starts allocating at the '_end' linker symbol 45 * The '_Min_Stack_Size' linker symbol reserves a memory for the MSP stack 46 * The implementation considers '_estack' linker symbol to be RAM end 47 * NOTE: If the MSP stack, at any point during execution, grows larger than the 48 * reserved size, please increase the '_Min_Stack_Size'. 49 * 50 * @param incr Memory size 51 * @return Pointer to allocated memory 52 */ 53 void* _sbrk(ptrdiff_t incr) 54 { 55 extern uint8_t _end; /* Symbol defined in the linker script */ 56 extern uint8_t _estack; /* Symbol defined in the linker script */ 57 extern uint32_t _Min_Stack_Size; /* Symbol defined in the linker script */ 58 const uint32_t stack_limit = (uint32_t) &_estack 59 - (uint32_t) &_Min_Stack_Size; 60 const uint8_t *max_heap = (uint8_t*) stack_limit; 61 uint8_t *prev_heap_end; 62 63 /* Initialize heap end at first call */ 64 if (NULL == __sbrk_heap_end) { 65 __sbrk_heap_end = &_end; 66 } 67 68 /* Protect heap from growing into the reserved MSP stack */ 69 if (__sbrk_heap_end + incr > max_heap) { 70 errno = ENOMEM; 71 return (void*) -1; 72 } 73 74 prev_heap_end = __sbrk_heap_end; 75 __sbrk_heap_end += incr; 76 77 return (void*) prev_heap_end; 78 }
