/** @file
  I/O Library. This file has compiler specifics for ICC as there
  is no ANSI C standard for doing IO.

  Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include "BaseIoLibIntrinsicInternal.h"

/**
  Reads an 8-bit I/O port.

  Reads the 8-bit I/O port specified by Port. The 8-bit read value is returned.
  This function must guarantee that all I/O read and write operations are
  serialized.

  If 8-bit I/O port operations are not supported, then ASSERT().

  @param  Port  The I/O port to read.

  @return The value read.

**/
UINT8
EFIAPI
IoRead8 (
  IN      UINTN                     Port
  )
{
  UINT8   Data;

  __asm {
    mov dx, word ptr [Port]
    in  al, dx

    mov Data, al
  }
  return Data;
}

/**
  Writes an 8-bit I/O port.

  Writes the 8-bit I/O port specified by Port with the value specified by Value
  and returns Value. This function must guarantee that all I/O read and write
  operations are serialized.

  If 8-bit I/O port operations are not supported, then ASSERT().

  @param  Port  The I/O port to write.
  @param  Value The value to write to the I/O port.

  @return The value written the I/O port.

**/
UINT8
EFIAPI
IoWrite8 (
  IN      UINTN                     Port,
  IN      UINT8                     Value
  )
{
  __asm {
    mov al, byte ptr [Value]
    mov dx, word ptr [Port]
    out dx, al
  }
  return Value;
}

/**
  Reads a 16-bit I/O port.

  Reads the 16-bit I/O port specified by Port. The 16-bit read value is returned.
  This function must guarantee that all I/O read and write operations are
  serialized.

  If 16-bit I/O port operations are not supported, then ASSERT().
  If Port is not aligned on a 16-bit boundary, then ASSERT().

  @param  Port  The I/O port to read.

  @return The value read.

**/
UINT16
EFIAPI
IoRead16 (
  IN      UINTN                     Port
  )
{
  UINT16  Data;

  ASSERT ((Port & 1) == 0);

  __asm {
    mov dx, word ptr [Port]
    in  ax, dx
    mov word ptr [Data], ax
  }

  return Data;
}

/**
  Writes a 16-bit I/O port.

  Writes the 16-bit I/O port specified by Port with the value specified by Value
  and returns Value. This function must guarantee that all I/O read and write
  operations are serialized.

  If 16-bit I/O port operations are not supported, then ASSERT().
  If Port is not aligned on a 16-bit boundary, then ASSERT().

  @param  Port  The I/O port to write.
  @param  Value The value to write to the I/O port.

  @return The value written the I/O port.

**/
UINT16
EFIAPI
IoWrite16 (
  IN      UINTN                     Port,
  IN      UINT16                    Value
  )
{
  ASSERT ((Port & 1) == 0);

  __asm {
    mov ax, word ptr [Value]
    mov dx, word ptr [Port]
    out dx, ax
  }

  return Value;
}

/**
  Reads a 32-bit I/O port.

  Reads the 32-bit I/O port specified by Port. The 32-bit read value is returned.
  This function must guarantee that all I/O read and write operations are
  serialized.

  If 32-bit I/O port operations are not supported, then ASSERT().
  If Port is not aligned on a 32-bit boundary, then ASSERT().

  @param  Port  The I/O port to read.

  @return The value read.

**/
UINT32
EFIAPI
IoRead32 (
  IN      UINTN                     Port
  )
{
  UINT32 Data;

  ASSERT ((Port & 3) == 0);

  __asm {
    mov dx, word ptr [Port]
    in  eax, dx
    mov dword ptr [Data], eax
  }

  return Data;
}

/**
  Writes a 32-bit I/O port.

  Writes the 32-bit I/O port specified by Port with the value specified by Value
  and returns Value. This function must guarantee that all I/O read and write
  operations are serialized.

  If 32-bit I/O port operations are not supported, then ASSERT().
  If Port is not aligned on a 32-bit boundary, then ASSERT().

  @param  Port  The I/O port to write.
  @param  Value The value to write to the I/O port.

  @return The value written the I/O port.

**/
UINT32
EFIAPI
IoWrite32 (
  IN      UINTN                     Port,
  IN      UINT32                    Value
  )
{
  ASSERT ((Port & 3) == 0);

  __asm {
    mov eax, dword ptr [Value]
    mov dx, word ptr [Port]
    out dx, eax
  }

  return Value;
}