/* Copyright (C) 2021,2022 fef <owo@fef.moe>.  All rights reserved. */

#pragma once

/** @brief I/O port number for the PIC1 command channel */
#define X86_PORT_PIC1_CMD	0x20
/** @brief I/O port number for the PIC1 data channel */
#define X86_PORT_PIC1_DATA	0x21

/** @brief I/O port number for the keyboard data channel */
#define X86_PORT_KBD_DATA	0x60
/** @brief I/O port number for the keyboard status channel */
#define X86_PORT_KBD_STATUS	0x64

/** @brief I/O port number for the PIC2 command channel */
#define X86_PORT_PIC2_CMD	0xa0
/** @brief I/O port number for the PIC2 data channel */
#define X86_PORT_PIC2_DATA	0xa1

#ifndef _ASM_SOURCE

#include <gay/cdefs.h>
#include <gay/types.h>

/**
 * @brief Read a byte from the I/O bus.
 *
 * @param port Port number
 * @return The byte that was read
 */
static inline u8 x86_inb(u16 port)
{
	u8 data;

	__asm__ volatile(
"	inb	%w1,	%b0	\n"
	: "=a"(data)
	: "Nd"(port)
	);

	return data;
}

/**
 * @brief Read a word from the I/O bus.
 *
 * @param port Port number
 * @return The word that was read
 */
static inline u16 x86_inw(u16 port)
{
	u16 data;

	__asm__ volatile(
"	inw	%w1,	%w0	\n"
	: "=a"(data)
	: "Nd"(port)
	);

	return data;
}

/**
 * @brief Read a longword from the I/O bus.
 *
 * @param port Port number
 * @return The longword that was read
 */
static inline u32 x86_inl(u16 port)
{
	u32 data;

	__asm__ volatile(
"	inl	%w1,	%l0	\n"
	: "=a"(data)
	: "Nd"(port)
	);

	return data;
}

/**
 * @brief Write a byte to the I/O bus.
 *
 * @param port Port number
 * @param data Byte to send through the port
 */
static inline void x86_outb(u16 port, u8 data)
{
	__asm__ volatile(
"	outb	%b0,	%w1	\n"
	:
	: "a"(data), "Nd"(port)
	);
}

/**
 * @brief Write a word to the I/O bus.
 *
 * @param port Port number
 * @param data Word to send through the port
 */
static inline void x86_outw(u16 port, u16 data)
{
	__asm__ volatile(
"	outw	%w0,	%w1	\n"
	:
	: "a"(data), "Nd"(port)
	);
}

/**
 * @brief Write a longword to the I/O bus.
 *
 * @param port Port number
 * @param data Longword to send through the port
 */
static inline void x86_outl(u16 port, u32 data)
{
	__asm__ volatile(
"	outl	%l0,	%w1	\n"
	:
	: "a"(data), "Nd"(port)
	);
}

/** @brief Induce a brief CPU delay by writing zero to I/O port `0x80`. */
static inline void x86_io_wait(void)
{
	x86_outb(0x80, 0);
}

static __always_inline void x86_outb_wait(u16 port, u8 data)
{
	x86_outb(port, data);
	x86_io_wait();
}

static __always_inline void x86_outw_wait(u16 port, u16 data)
{
	x86_outw(port, data);
	x86_io_wait();
}

static __always_inline void x86_outl_wait(u16 port, u32 data)
{
	x86_outl(port, data);
	x86_io_wait();
}

#endif /* not _ASM_SOURCE */