caos-with-snake/drivers/port.h

#pragma once

static inline unsigned char port_byte_in(unsigned short port) {
    unsigned char result;
    asm volatile("in %%dx, %%al" : "=a" (result) : "d" (port));
    return result;
}

static inline unsigned short port_word_in(unsigned short port) {
    unsigned short result;
    asm volatile("in %%dx, %%ax" : "=a" (result) : "d" (port));
    return result;
}

static inline void port_byte_out(unsigned short port, unsigned char data) {
    asm volatile("outb %%al, %%dx" : : "a" (data), "d" (port));
}

static inline void port_word_out(unsigned short port, unsigned short data) {
    asm volatile("outw %%ax, %%dx" : : "a" (data), "d" (port));
}

/* assembler-long, not c-long */
static inline void port_long_out(unsigned short port, unsigned int data) {
    asm volatile("outl %%eax, %%dx" : : "a" (data), "d" (port));
}