defs.h

fairysky系统,是一个小型的内核,模拟linux原始版本的

/*文件名: defs.h
  说明:   i386段结构等定义
  作者:   marsinfan
  日期:   2005/12/10
*/

#ifndef _defs_h_
#define _defs_h_

#include "types.h"

/* 端口 */
#define PORT_8259M      0x20
#define PORT_8259S      0xA0
#define PORT_KBD_A      0x60

#define EOI             0x20

/* 访问标志 */
#define ACS_PRESENT     0x80            /* present segment */
#define ACS_CSEG        0x18            /* 代码段 */
#define ACS_DSEG        0x10            /* 数据段 */
#define ACS_CONFORM     0x04            /* conforming segment */
#define ACS_READ        0x02            /* 可读段 */
#define ACS_WRITE       0x02            /* 可写段 */
#define ACS_IDT         ACS_DSEG        /* segment type is the same type */
#define ACS_INT_GATE    0x0E            /* int gate for 386 */
#define ACS_TRAP_GATE   0x0F            /* TRAP gate for 386 */
#define ACS_INT         (ACS_PRESENT | ACS_INT_GATE) /* present int gate */
#define ACS_TRAP         (ACS_PRESENT| ACS_TRAP_GATE) /* present int gate */
#define ACS_TSS_GATE    0x09
#define ACS_TSS         (ACS_PRESENT | ACS_TSS_GATE) /* present tss gate */
#define ACS_DPL_0       0x00            /* descriptor privilege level #0 */
//#define ACS_DPL_1       0x20            /* descriptor privilege level #1 */
//#define ACS_DPL_2       0x40            /* descriptor privilege level #2 */
#define ACS_DPL_3       0x60            /* descriptor privilege level #3 */
//#define ACS_LDT         0x02            /* ldt descriptor */

/* Ready-made values */
#define ACS_CODE        (ACS_PRESENT | ACS_CSEG | ACS_READ)
#define ACS_DATA        (ACS_PRESENT | ACS_DSEG | ACS_WRITE)
#define ACS_STACK       (ACS_PRESENT | ACS_DSEG | ACS_WRITE)

/* Attributes (in turms of size) */
#define ATTR_GRANULARITY 0x80           /* segment limit is given in 4KB pages rather than in bytes */
#define ATTR_BIG         0x40           /* ESP is used rather than SP */
#define ATTR_DEFAULT     0x40           /* 32-bit code segment rather than 16-bit */


/* 段描述符定义 */
typedef struct
{
    u16 limit, base_l;
    u8 base_m, access, attribs, base_h;
} __attribute__((packed)) DESCR_SEG;

/* GDTR 寄存器定义 */
typedef struct
{
    u16 limit;
    u32 base;
} __attribute__((packed)) GDTR;

/* 中断描述符定义 */
typedef struct
{
    u16 offset_l;
    u16 selector ;
    u8 param_cnt;
    u8 access;
    u16 offset_h;
} __attribute__((packed)) DESCR_INT;

/* IDTR 寄存器定义 */
typedef struct
{
    u16 limit;
    u32 base      ;
} __attribute__((packed)) IDTR;



#endif