libgloss/ft32/sbrk.c

   1 /* sbrk.c -- allocate memory dynamically.
   2  *
   3  *
   4  * Copyright (C) 2015 FTDI (support@ftdichip.com)
   5  *
   6  * The authors hereby grant permission to use, copy, modify, distribute,
   7  * and license this software and its documentation for any purpose, provided
   8  * that existing copyright notices are retained in all copies and that this
   9  * notice is included verbatim in any distributions. No written agreement,
  10  * license, or royalty fee is required for any of the authorized uses.
  11  * Modifications to this software may be copyrighted by their authors
  12  * and need not follow the licensing terms described here, provided that
  13  * the new terms are clearly indicated on the first page of each file where
  14  * they apply.
  15  */
  16 #include <errno.h>
  17 #include "glue.h"
  18
  19 char *__heap_ptr = (char *)&_end;
  20
  21 /*
  22  * sbrk -- changes heap size size. Get nbytes more
  23  *         RAM. We just increment a pointer in what's
  24  *         left of memory on the board.
  25  */
  26 char *
  27 _sbrk (nbytes)
  28      int nbytes;
  29 {
  30   char *base;
  31   char *sp;
  32   char canary;
  33
  34   if ((__heap_ptr + nbytes) < (&canary - 2000))
  35     {
  36       base = __heap_ptr;
  37       __heap_ptr += nbytes;
  38       return base;
  39     }
  40     else
  41     {
  42       errno = ENOMEM;
  43       return ((char *)-1);
  44     }
  45 }