sbrk.c

ucOS 在单片机上实现

/*****************************************************************************************
 ** FILE        : Sbrk.C                                               	     			**
 ** DESCRIPTION : This file is generated by Hitachi Project Generator (Ver.1.2)			**
 **                                        												**
 **-------------------------------------------------------------------------------------**
 **                                                                                     **
 **          Copyright (c) 2001-2002 Hitachi Micro Systems Europe Ltd UK.		        **
 **                                                                                     **
 ** 			This program is distributed in the hope that it will be useful,         **
 **				but WITHOUT ANY WARRANTY; without even the implied warranty of          **
 **				MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.                    **
 **                                                                                     **
 *****************************************************************************************/

#include <stdio.h>
#include "sbrk.h"

//const size_t _sbrk_size=		/* Specifies the minimum unit of	*/
								/* the defined heap area			*/ 

static  union  {
		long  dummy ;        /* Dummy for 4-byte boundary          */
		char heap[HEAPSIZE]; /* Declaration of the area managed   */
                             /*                           by sbrk */
 }heap_area ;

static  char  *brk=(char *)&heap_area;/* End address of area assigned     */

/**************************************************************************/
/*     sbrk:Data write							  						  */
/*	    Return value:Start address of the assigned area (Pass)	  		  */
/*	                 -1				    (Failure)	  					  */
/**************************************************************************/
char  *sbrk(size_t size)		   /* Assigned area size	  */
{
      char  *p;

      if(brk+size>heap_area.heap+HEAPSIZE) /* Empty area size		  */
	   return (char *)-1 ;

      p=brk ;				   /* Area assignment		  */
      brk += size ;			   /* End address update	  */
      return p ;
}