src/lib/ddk/include/hw/inout.h

// Copyright 2016 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef SRC_LIB_DDK_INCLUDE_HW_INOUT_H_
#define SRC_LIB_DDK_INCLUDE_HW_INOUT_H_

#include <stdint.h>
#include <zircon/compiler.h>

__BEGIN_CDECLS

#if defined(__x86_64__) || defined(__i386__)
static inline uint8_t inp(uint16_t _port) {
  uint8_t rv;
  __asm__ __volatile__("inb %1, %0" : "=a"(rv) : "d"(_port));
  return (rv);
}

static inline uint16_t inpw(uint16_t _port) {
  uint16_t rv;
  __asm__ __volatile__("inw %1, %0" : "=a"(rv) : "d"(_port));
  return (rv);
}

static inline uint32_t inpd(uint16_t _port) {
  uint32_t rv;
  __asm__ __volatile__("inl %1, %0" : "=a"(rv) : "d"(_port));
  return (rv);
}

static inline void outp(uint16_t _port, uint8_t _data) {
  __asm__ __volatile__("outb %1, %0" : : "d"(_port), "a"(_data));
}

static inline void outpw(uint16_t _port, uint16_t _data) {
  __asm__ __volatile__("outw %1, %0" : : "d"(_port), "a"(_data));
}

static inline void outpd(uint16_t _port, uint32_t _data) {
  __asm__ __volatile__("outl %1, %0" : : "d"(_port), "a"(_data));
}
#else
static inline uint8_t inp(uint16_t _port) { return 0; }
static inline uint16_t inpw(uint16_t _port) { return 0; }
static inline uint32_t inpd(uint16_t _port) { return 0; }
static inline void outp(uint16_t _port, uint8_t _data) {}
static inline void outpw(uint16_t _port, uint16_t _data) {}
static inline void outpd(uint16_t _port, uint32_t _data) {}
#endif

__END_CDECLS

#endif  // SRC_LIB_DDK_INCLUDE_HW_INOUT_H_