/** @file
  I/O Library. This file has compiler specifics for ICC as there
  is no ANSI C standard for doing IO.

  Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
  This program and the accompanying materials are
  licensed and made available under the terms and conditions of the BSD License
  which accompanies this distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php.

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/

#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;
}