const.h

这是《自己动手写操作系统》的原文件和代码

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                            const.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                                                    Forrest Yu, 2005
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

#ifndef	_TINIX_CONST_H_
#define	_TINIX_CONST_H_


/* EXTERN */
#define	EXTERN	extern	/* EXTERN is defined as extern except in global.c */

/* 函数类型 */
#define	PUBLIC		/* PUBLIC is the opposite of PRIVATE */
#define	PRIVATE	static	/* PRIVATE x limits the scope of x */

/* Boolean */
#define	TRUE	1
#define	FALSE	0

/* GDT 和 IDT 中描述符的个数 */
#define	GDT_SIZE	128
#define	IDT_SIZE	256

/* 权限 */
#define	PRIVILEGE_KRNL	0
#define	PRIVILEGE_TASK	1
#define	PRIVILEGE_USER	3

/* 8259A interrupt controller ports. */
#define	INT_M_CTL	0x20	/* I/O port for interrupt controller         <Master> */
#define	INT_M_CTLMASK	0x21	/* setting bits in this port disables ints   <Master> */
#define	INT_S_CTL	0xA0	/* I/O port for second interrupt controller  <Slave>  */
#define	INT_S_CTLMASK	0xA1	/* setting bits in this port disables ints   <Slave>  */


#endif /* _TINIX_CONST_H_ */