这是DOS系统的源代码,汇编写的,值得看看,对开发操作系统的人员有价值

				/* standard.h - included in every C module			*/
				/*																	*/
				/* defines things that every C module is likely		*/
				/* to want defined											*/
				
				typedef unsigned short	ushort;
				typedef unsigned long	ulong;
				typedef unsigned char	uchar;
				typedef ushort		word;
				typedef ulong		dword;
				typedef uchar		byte;
				typedef uchar		bool;
				typedef word		boolean;
				
				#define NULL		0
				#define FALSE		0
				#define TRUE		1
				#define UNDEFINED	0xffff