sbrk.c

来自「ULTRACTR的源码」· C语言 代码 · 共 49 行

/*-----------------------------------------------------------------------------
//     $Date: 2003/10/09 23:43:01 $
//     $RCSfile: sbrk.c,v $
//-----------------------------------------------------------------------------
//
//     XILINX IS PROVIDING THIS DESIGN, CODE, OR INFORMATION "AS IS"
//     SOLELY FOR USE IN DEVELOPING PROGRAMS AND SOLUTIONS FOR
//     XILINX DEVICES.  BY PROVIDING THIS DESIGN, CODE, OR INFORMATION
//     AS ONE POSSIBLE IMPLEMENTATION OF THIS FEATURE, APPLICATION
//     OR STANDARD, XILINX IS MAKING NO REPRESENTATION THAT THIS
//     IMPLEMENTATION IS FREE FROM ANY CLAIMS OF INFRINGEMENT,
//     AND YOU ARE RESPONSIBLE FOR OBTAINING ANY RIGHTS YOU MAY REQUIRE
//     FOR YOUR IMPLEMENTATION.  XILINX EXPRESSLY DISCLAIMS ANY
//     WARRANTY WHATSOEVER WITH RESPECT TO THE ADEQUACY OF THE
//     IMPLEMENTATION, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OR
//     REPRESENTATIONS THAT THIS IMPLEMENTATION IS FREE FROM CLAIMS OF
//     INFRINGEMENT, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
//     FOR A PARTICULAR PURPOSE.
//     
//     (c) Copyright 2002 Xilinx, Inc.
//     All rights reserved.
//
//---------------------------------------------------------------------------*/

#include <errno.h>

extern char _heap_start[];
extern char _heap_end[];

static char *heap_ptr;

char *sbrk (int nbytes)
{
  char *base;

  if (!heap_ptr)
    heap_ptr = (char *)&_heap_start;
  base = heap_ptr;
  heap_ptr += nbytes;

  if (heap_ptr <= (char *)&_heap_end)
    return base;
  else
  {
    errno = ENOMEM;
    return ((char *)-1);
  }
}