#ifndef FOOLOS_X86_H
#define FOOLOS_X86_H

/**
 * @file
 *
 * X86 32-bit Basics
 * =================
 *
 * **All the functions are very specific to the targeted x86 architecture.**
 *
 * This is the header of our basic **x86** function definitions.
 * Most of the functions are implemented in assembler in the file _asm/x86.s_,
 * however a few short helper functions are defined in this header itself:
 *
 * * x86_set_page_directory()
 * * x86_paging_enable()
 * * x86_paging_disable()
 *
 *
 * Reading and Writing Ports
 * -------------------------
 *
 * The functions of the form x86_outX() and x86_inX(), where the X 
 * indicates the value size allow reading and writing ports.
 *
 * * x86_outb() / x86_inb()
 * * x86_outw() / x86_inw()
 * * x86_outl() / x86_inl()
 *
 * The sizes are:
 *
 * * b - byte (8 bit)
 * * w - word (16 bit)
 * * l - double word (32 bit)
 *
 * Remember, that the port address is always 32 bits wide.
 *
 * Dependencies
 * ------------
 *
 * All we need are uint32_t, uint16_t and uint8_t as provided by <stdint.h>
 *
 * References
 * ----------
 * * http://wiki.osdev.org/Interrupt_Service_Routines
 * * https://wiki.osdev.org/CPU_Registers_x86
 * * ...
 *
 */

// we need uint32_t, uint16_t, uint8_t //
#include <stdint.h>

/** write byte to port */
void     x86_outb (uint32_t port, uint8_t data);

/** read byte from port */
uint8_t  x86_inb  (uint32_t port);

/** write word to port */
void     x86_outw (uint32_t port, uint16_t data);

/** read word from port */
uint16_t x86_inw  (uint32_t port);

/** write double word to port */
void     x86_outl (uint32_t port, uint32_t data);

/** read double word from port */
uint32_t x86_inl  (uint32_t port);

/** disable interrupts */
void     x86_cli  ();

/** enable interrupts */
void     x86_sti  ();

/** xchg - this can be used for semaphors and simlar */
uint8_t  x86_xchg (uint32_t addr, uint32_t val);

/** invlpg - invalidate translation lookaside buffer */
void     x86_invlpg(uint32_t addr);

/** read value from control register specified by num */
uint32_t x86_get_cr(uint8_t num);

/** write given value to the control register specified by num */
void     x86_set_cr(uint8_t num, uint32_t value);

/** Set the address of the page directory. This is required **before** enabling paging */
static inline void x86_set_page_directory(uint32_t pdir_addr) {x86_set_cr(3,pdir_addr);}

/** Get the address of the page directory. */
static inline uint32_t x86_get_page_directory() {return x86_get_cr(3);}

/** Enable paging */
static inline void x86_paging_enable()    {x86_set_cr(0,x86_get_cr(0)| 0x80000000);}

/** Disable paging */
static inline void x86_paging_disable()   {x86_set_cr(0,x86_get_cr(0)&~0x80000000);}

#endif