text: /**
  *****************************************************************************
  **
  **  File        : sysmem.c
  **
  **  Author        : Auto-generated by STM32CubeIDE
  **
  **  Abstract    : STM32CubeIDE Minimal System Memory calls file
  **
  **                   For more information about which c-functions
  **                need which of these lowlevel functions
  **                please consult the Newlib libc-manual
  **
  **  Environment : STM32CubeIDE MCU
  **
  **  Distribution: The file is distributed as is, without any warranty
  **                of any kind.
  **
  *****************************************************************************
  **
  ** <h2><center>&copy; COPYRIGHT(c) 2018 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.
  **
  **
  *****************************************************************************
  */
  
  /* Includes */
  #include <errno.h>
  #include <stdio.h>
  
  /* Variables */
  extern int errno;
  register char * stack_ptr asm("sp");
  
  /* Functions */
  
  /**
   _sbrk
   Increase program data space. Malloc and related functions depend on this
  **/
  caddr_t _sbrk(int incr)
  {
      extern char end asm("end");
      static char *heap_end;
      char *prev_heap_end;
  
      if (heap_end == 0)
          heap_end = &end;
  
      prev_heap_end = heap_end;
      if (heap_end + incr > stack_ptr)
      {
          errno = ENOMEM;
          return (caddr_t) -1;
      }
  
      heap_end += incr;
  
      return (caddr_t) prev_heap_end;
  }
  
  