fat32nextcluster.c

c51文件系统源码

#ifndef _FAT32_DEFINE
 #include "FAT32.c"
#endif

DWORD FAT32NextCluster(DWORD CurrentCluster);

DWORD FAT32NextCluster(DWORD CurrentCluster)
{
	register BYTE Offset,i;
	xdata DWORD Sector;

	Sector=CurrentCluster>>7;						//等价于CurrentCluster/128
	Offset=(BYTE)(CurrentCluster&0x0000007f);		//等价于CurrentCluster%128
	if (Sector!=FAT.Sector)
	{
		IDEReadSector(FAT32.FATSec + Sector);
		for(i=0;i<128;i++)
			FAT.FAT[i]=((DWORD *)&DiskBuffer)[i];
		FAT.Sector=Sector;
	}
	return(MEMSwap32(FAT.FAT[Offset]));
}