#include "util.h"

/**
 * Wrapper function that reads a byte from the specified I/O port.
 *
 * "=a" (result) - put al register in the `result` var when finished
 * "d" (port) - load edx with the specified `port`
 *
 * @param port
 * @return the read byte
 */
u8_t io_byte_in(u16_t port) {
    u8_t result;
    __asm__("in %%dx, %%al" : "=a" (result) : "d" (port));
    return result;
}

/**
 * Wrapper function that writes a byte to the specified I/O port.
 *
 * "a" (data) - load eal with `data`
 * "d" (port) - load edx with `port`
 *
 * @param port
 * @param data
 */
void io_byte_out(u16_t port, u8_t data) {
    __asm__("out %%al, %%dx" : : "a" (data), "d" (port));
}

/**
 * Wrapper function that reads a word from the specified I/O port.
 *
 * "=a" (result) - put eax register in the `result` var when finished
 * "d" (port) - load edx with the specified `port`
 *
 * @param port
 * @return the read word
 */
u16_t io_word_in(u16_t port) {
    u16_t result;
    __asm__("in %%dx, %%ax" : "=a" (result) : "d" (port));
    return result;
}

/**
 * Wrapper function that writes a word to the specified I/O port.
 *
 * "a" (data) - load eax with `data`
 * "d" (port) - load edx with `port`
 *
 * @param port
 * @param data
 */
void io_word_out(u16_t port, u16_t data) {
    __asm__("out %%ax, %%dx" : : "a" (data), "d" (port));
}