tables.h File Reference

#include "system.h"

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Data Structures
struct	idt_entry_struct
struct	idt_struct
struct	gdt_descriptor_struct
struct	gdt_entry_struct

Functions
struct idt_entry_struct	__attribute__ ((packed)) idt_entry
void	idt_set_gate (u8int idx, u32int base, u16int sel, u8int flags)
void	gdt_init_entry (int idx, u32int base, u32int limit, u8int access, u8int flags)
void	init_idt ()
void	init_gdt ()

Variables
u16int	base_low
u16int	sselect
u8int	zero
u8int	flags
u16int	base_high
u16int	limit
u32int	base
u16int	limit_low
u8int	base_mid
u8int	access

Function Documentation

struct idt_entry_struct __attribute__

(

(packed)

)

void gdt_init_entry	(	int	idx,
		u32int	base,
		u32int	limit,
		u8int	access,
		u8int	flags
	)

Definition at line 57 of file tables.c.

References access, and gdt_entries.

Referenced by init_gdt().

{
  gdt_entry *new_entry = &gdt_entries[idx];
  new_entry->base_low  = (base & 0xFFFF);
  new_entry->base_mid  = (base >> 16) & 0xFF;
  new_entry->base_high = (base >> 24) & 0xFF;
  new_entry->limit_low = (limit & 0xFFFF);
  new_entry->flags  = (limit >> 16) & 0xFF;
  new_entry->flags |= flags & 0xF0;
  new_entry->access = access;
}

void idt_set_gate	(	u8int	idx,
		u32int	base,
		u16int	sel,
		u8int	flags
	)

Definition at line 27 of file tables.c.

References flags, and idt_entries.

Referenced by init_irq().

{
  idt_entry *new_entry = &idt_entries[idx];
  new_entry->base_low  = (base &  0xFFFF);
  new_entry->base_high = (base >> 16) & 0xFFFF;
  new_entry->sselect   = sel;
  new_entry->zero = 0;
  new_entry->flags = flags;
}

void init_gdt

(

)

Definition at line 75 of file tables.c.

References gdt_entries, gdt_init_entry(), gdt_ptr, limit, and write_gdt_ptr().

Referenced by kmain().

{
  gdt_ptr.limit = 5 * sizeof(gdt_entry) - 1;
  gdt_ptr.base  = (u32int) gdt_entries;

  u32int limit = 0xFFFFFFFF;
  gdt_init_entry(0, 0, 0, 0, 0);           //required null segment
  gdt_init_entry(1, 0, limit, 0x9A, 0xCF); //code segment
  gdt_init_entry(2, 0, limit, 0x92, 0xCF); //data segment
  gdt_init_entry(3, 0, limit, 0xFA, 0xCF); //user mode code segment
  gdt_init_entry(4, 0, limit, 0xF2, 0xCF); //user mode data segment

  write_gdt_ptr((u32int) &gdt_ptr, sizeof(gdt_ptr));
}

void init_idt

(

)

Definition at line 43 of file tables.c.

References idt_entries, idt_ptr, memset(), and write_idt_ptr().

Referenced by kmain().

{
  idt_ptr.limit = 256*sizeof(idt_descriptor) - 1;
  idt_ptr.base  = (u32int)idt_entries;
  memset(idt_entries, 0, 256*sizeof(idt_descriptor));
  
  write_idt_ptr((u32int)&idt_ptr);
}

Variable Documentation

u8int access

Definition at line 55 of file tables.h.

Referenced by gdt_init_entry().

u32int base

Definition at line 53 of file tables.h.

Referenced by alloc().

u8int base_high

Definition at line 56 of file tables.h.

u16int base_low

Definition at line 52 of file tables.h.

u8int base_mid

Definition at line 54 of file tables.h.

u8int flags

Definition at line 55 of file tables.h.

Referenced by idt_set_gate().

u16int limit

Definition at line 52 of file tables.h.

Referenced by init_gdt().

u16int limit_low

Definition at line 52 of file tables.h.

u16int sselect

Definition at line 53 of file tables.h.

u8int zero

Definition at line 54 of file tables.h.