#ifndef __KERNEL_GLOBAL_H
#define __KERNEL_GLOBAL_H
#include "stdint.h"


// ----------------  GDT描述符属性  ----------------

#define	DESC_G_4K    1
#define	DESC_D_32    1
#define DESC_L	     0	// 64位代码标记，此处标记为0便可。
#define DESC_AVL     0	// cpu不用此位，暂置为0  
#define DESC_P	     1
#define DESC_DPL_0   0
#define DESC_DPL_1   1
#define DESC_DPL_2   2
#define DESC_DPL_3   3
/* 
   代码段和数据段属于存储段，tss和各种门描述符属于系统段
   s为1时表示存储段,为0时表示系统段.
*/
#define DESC_S_CODE	1
#define DESC_S_DATA	DESC_S_CODE
#define DESC_S_SYS	0
#define DESC_TYPE_CODE	8	// x=1,c=0,r=0,a=0 代码段是可执行的,非依从的,不可读的,已访问位a清0.  
#define DESC_TYPE_DATA  2	// x=0,e=0,w=1,a=0 数据段是不可执行的,向上扩展的,可写的,已访问位a清0.
#define DESC_TYPE_TSS   9	// B位为0,不忙


#define	 RPL0  0
#define	 RPL1  1
#define	 RPL2  2
#define	 RPL3  3

#define TI_GDT 0
#define TI_LDT 1

#define SELECTOR_K_CODE	   ((1 << 3) + (TI_GDT << 2) + RPL0)
#define SELECTOR_K_DATA	   ((2 << 3) + (TI_GDT << 2) + RPL0)
#define SELECTOR_K_STACK   SELECTOR_K_DATA 
#define SELECTOR_K_GS	   ((3 << 3) + (TI_GDT << 2) + RPL0)
/* 第3个段描述符是显存,第4个是tss */
#define SELECTOR_U_CODE	   ((5 << 3) + (TI_GDT << 2) + RPL3)
#define SELECTOR_U_DATA	   ((6 << 3) + (TI_GDT << 2) + RPL3)
#define SELECTOR_U_STACK   SELECTOR_U_DATA

#define GDT_ATTR_HIGH		 ((DESC_G_4K << 7) + (DESC_D_32 << 6) + (DESC_L << 5) + (DESC_AVL << 4))
#define GDT_CODE_ATTR_LOW_DPL3	 ((DESC_P << 7) + (DESC_DPL_3 << 5) + (DESC_S_CODE << 4) + DESC_TYPE_CODE)
#define GDT_DATA_ATTR_LOW_DPL3	 ((DESC_P << 7) + (DESC_DPL_3 << 5) + (DESC_S_DATA << 4) + DESC_TYPE_DATA)


//---------------  TSS描述符属性  ------------
#define TSS_DESC_D  0 

#define TSS_ATTR_HIGH ((DESC_G_4K << 7) + (TSS_DESC_D << 6) + (DESC_L << 5) + (DESC_AVL << 4) + 0x0)
#define TSS_ATTR_LOW ((DESC_P << 7) + (DESC_DPL_0 << 5) + (DESC_S_SYS << 4) + DESC_TYPE_TSS)
#define SELECTOR_TSS ((4 << 3) + (TI_GDT << 2 ) + RPL0)

struct gdt_desc {
   uint16_t limit_low_word;
   uint16_t base_low_word;
   uint8_t  base_mid_byte;
   uint8_t  attr_low_byte;
   uint8_t  limit_high_attr_high;
   uint8_t  base_high_byte;
}; 


//--------------   IDT描述符属性  ------------
#define	 IDT_DESC_P	 1 
#define	 IDT_DESC_DPL0   0
#define	 IDT_DESC_DPL3   3
#define	 IDT_DESC_32_TYPE     0xE   // 32位的门
#define	 IDT_DESC_16_TYPE     0x6   // 16位的门，不用，定义它只为和32位门区分
#define	 IDT_DESC_ATTR_DPL0  ((IDT_DESC_P << 7) + (IDT_DESC_DPL0 << 5) + IDT_DESC_32_TYPE)
#define	 IDT_DESC_ATTR_DPL3  ((IDT_DESC_P << 7) + (IDT_DESC_DPL3 << 5) + IDT_DESC_32_TYPE)


#define NULL ((void*)0)
#define bool int
#define true 1
#define false 0

#define PG_SIZE 4096

#endif