sbrk.c

来自「用中断的方式控制lcd的显示」· C语言 代码 · 共 43 行

/***********************************************************************/
/*                                                                     */
/*  FILE        :sbrk.c                                                */
/*  DATE        :Tue, Apr 17, 2007                                     */
/*  DESCRIPTION :Program of sbrk                                       */
/*  CPU TYPE    :H8/3664F                                              */
/*                                                                     */
/*  This file is generated by Renesas Project Generator (Ver.3.1).     */
/*                                                                     */
/***********************************************************************/
                  


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

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

#pragma pack 2
static  union {
	short  dummy ;              /* Dummy for 2-byte boundary */
	char heap[HEAPSIZE];        /* Declaration of the area managed by sbrk */
 }heap_area ;
#pragma unpack

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

/*****************************************************************************/
/*    sbrk: Data write                                                     	 */
/*           Return value: Start address of the assigned area (Pass)      	 */
/*                         -1                                 (Failure)      */
/*****************************************************************************/
extern  char  *sbrk(int 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 ;
}