#ifndef CONSTS_H
#define CONSTS_H

#define NR_TASKS             0

/* Table sizes. */
#define GDT_SIZE (FIRST_LDT_INDEX + NR_TASKS)
//#define IDT_SIZE (IRQ8_VECTOR + 8)	/* only up to the highest vector */

/* Fixed global descriptors.  1 to 7 are prescribed by the BIOS. */
#define CS_INDEX             1
#define DS_INDEX             2
#define TSS_INDEX            3  /* Kernel TSS */
#define IDT_INDEX            4
#define FIRST_LDT_INDEX      5

#define CS_SELECTOR       0x08	/* (CS_INDEX * DESC_SIZE) */
#define DS_SELECTOR       0x10
#define TSS_SELECTOR      0x18
#define IDT_SELECTOR      0x20

/* Descriptor structure offsets. */
#define DESC_BASE            2	/* to base_low */
#define DESC_BASE_MIDDLE     4	/* to base_middle */
#define DESC_ACCESS          5	/* to access byte */
#define DESC_SIZE            8	/* sizeof (struct segdesc_s) */

/* Base and limit sizes and shifts. */
#define BASE_MIDDLE_SHIFT   16	/* shift for base --> base_middle */

/* Access-byte and type-byte bits. */
#define PRESENT           0x80	/* set for descriptor present */
#define DPL               0x60	/* descriptor privilege level mask */
#define DPL_SHIFT            5
#define SEGMENT           0x10	/* set for segment-type descriptors */

/* Access-byte bits. */
#define EXECUTABLE        0x08	/* set for executable segment */
#define CONFORMING        0x04	/* set for conforming segment if executable */
#define EXPAND_DOWN       0x04	/* set for expand-down segment if !executable*/
#define READABLE          0x02	/* set for readable segment if executable */
#define WRITEABLE         0x02	/* set for writeable segment if !executable */
#define TSS_BUSY          0x02	/* set if TSS descriptor is busy */
#define ACCESSED          0x01	/* set if segment accessed */

/* i386 paging constants */
#define VM_PRESENT 0x001   /* Page is present */
#define VM_WRITE   0x002   /* Read/write access allowed */
#define VM_USER    0x004   /* User access allowed */
#define VM_PWT     0x008   /* Write through */
#define VM_PCD     0x010   /* Cache disable */
#define VM_ACC     0x020   /* Accessed */
#define VM_ADDR_MASK 0xFFFFF000 /* physical address */

#define VM_DIR_ENTRIES     512    /* Number of entries in a page dir */
#define VM_PT_ENTRIES      512    /* Number of entries in a page table */

#define PAGE_SIZE  4096

#endif