MdePkg/Library/BaseIoLibIntrinsic/IoLibMsc.c

   1 /** @file
   2   I/O Library. This file has compiler specifics for Microsft C as there is no
   3   ANSI C standard for doing IO.
   4
   5   MSC - uses intrinsic functions and the optimize will remove the function call
   6   overhead.
   7
   8   We don't advocate putting compiler specifics in libraries or drivers but there
   9   is no other way to make this work.
  10
  11   Copyright (c) 2006 - 2008, Intel Corporation<BR>
  12   All rights reserved. This program and the accompanying materials
  13   are licensed and made available under the terms and conditions of the BSD License
  14   which accompanies this distribution.  The full text of the license may be found at
  15   http://opensource.org/licenses/bsd-license.php
  16
  17   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  18   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  19
  20 **/
  21
  22
  23
  24 #include "BaseIoLibIntrinsicInternal.h"
  25
  26 //
  27 // Microsoft Visual Studio 7.1 Function Prototypes for I/O Intrinsics.
  28 //
  29
  30 int            _inp (unsigned short port);
  31 unsigned short _inpw (unsigned short port);
  32 unsigned long  _inpd (unsigned short port);
  33 int            _outp (unsigned short port, int databyte );
  34 unsigned short _outpw (unsigned short port, unsigned short dataword );
  35 unsigned long  _outpd (unsigned short port, unsigned long dataword );
  36 void          _ReadWriteBarrier (void);
  37
  38 #pragma intrinsic(_inp)
  39 #pragma intrinsic(_inpw)
  40 #pragma intrinsic(_inpd)
  41 #pragma intrinsic(_outp)
  42 #pragma intrinsic(_outpw)
  43 #pragma intrinsic(_outpd)
  44 #pragma intrinsic(_ReadWriteBarrier)
  45
  46 //
  47 // _ReadWriteBarrier() forces memory reads and writes to complete at the point
  48 // in the call. This is only a hint to the compiler and does emit code.
  49 // In past versions of the compiler, _ReadWriteBarrier was enforced only
  50 // locally and did not affect functions up the call tree. In Visual C++
  51 // 2005, _ReadWriteBarrier is enforced all the way up the call tree.
  52 //
  53
  54 /**
  55   Reads an 8-bit I/O port.
  56
  57   Reads the 8-bit I/O port specified by Port. The 8-bit read value is returned.
  58   This function must guarantee that all I/O read and write operations are
  59   serialized.
  60
  61   If 8-bit I/O port operations are not supported, then ASSERT().
  62
  63   @param  Port  The I/O port to read.
  64
  65   @return The value read.
  66
  67 **/
  68 UINT8
  69 EFIAPI
  70 IoRead8 (
  71   IN      UINTN                     Port
  72   )
  73 {
  74   UINT8                             Value;
  75
  76   _ReadWriteBarrier ();
  77   Value = (UINT8)_inp ((UINT16)Port);
  78   _ReadWriteBarrier ();
  79   return Value;
  80 }
  81
  82 /**
  83   Writes an 8-bit I/O port.
  84
  85   Writes the 8-bit I/O port specified by Port with the value specified by Value
  86   and returns Value. This function must guarantee that all I/O read and write
  87   operations are serialized.
  88
  89   If 8-bit I/O port operations are not supported, then ASSERT().
  90
  91   @param  Port  The I/O port to write.
  92   @param  Value The value to write to the I/O port.
  93
  94   @return The value written the I/O port.
  95
  96 **/
  97 UINT8
  98 EFIAPI
  99 IoWrite8 (
 100   IN      UINTN                     Port,
 101   IN      UINT8                     Value
 102   )
 103 {
 104   _ReadWriteBarrier ();
 105   (UINT8)_outp ((UINT16)Port, Value);
 106   _ReadWriteBarrier ();
 107   return Value;
 108 }
 109
 110 /**
 111   Reads a 16-bit I/O port.
 112
 113   Reads the 16-bit I/O port specified by Port. The 16-bit read value is returned.
 114   This function must guarantee that all I/O read and write operations are
 115   serialized.
 116
 117   If 16-bit I/O port operations are not supported, then ASSERT().
 118   If Port is not aligned on a 16-bit boundary, then ASSERT().
 119
 120   @param  Port  The I/O port to read.
 121
 122   @return The value read.
 123
 124 **/
 125 UINT16
 126 EFIAPI
 127 IoRead16 (
 128   IN      UINTN                     Port
 129   )
 130 {
 131   UINT16                            Value;
 132
 133   ASSERT ((Port & 1) == 0);
 134   _ReadWriteBarrier ();
 135   Value = _inpw ((UINT16)Port);
 136   _ReadWriteBarrier ();
 137   return Value;
 138 }
 139
 140 /**
 141   Writes a 16-bit I/O port.
 142
 143   Writes the 16-bit I/O port specified by Port with the value specified by Value
 144   and returns Value. This function must guarantee that all I/O read and write
 145   operations are serialized.
 146
 147   If 16-bit I/O port operations are not supported, then ASSERT().
 148   If Port is not aligned on a 16-bit boundary, then ASSERT().
 149
 150   @param  Port  The I/O port to write.
 151   @param  Value The value to write to the I/O port.
 152
 153   @return The value written the I/O port.
 154
 155 **/
 156 UINT16
 157 EFIAPI
 158 IoWrite16 (
 159   IN      UINTN                     Port,
 160   IN      UINT16                    Value
 161   )
 162 {
 163   ASSERT ((Port & 1) == 0);
 164   _ReadWriteBarrier ();
 165   _outpw ((UINT16)Port, Value);
 166   _ReadWriteBarrier ();
 167   return Value;
 168 }
 169
 170 /**
 171   Reads a 32-bit I/O port.
 172
 173   Reads the 32-bit I/O port specified by Port. The 32-bit read value is returned.
 174   This function must guarantee that all I/O read and write operations are
 175   serialized.
 176
 177   If 32-bit I/O port operations are not supported, then ASSERT().
 178   If Port is not aligned on a 32-bit boundary, then ASSERT().
 179
 180   @param  Port  The I/O port to read.
 181
 182   @return The value read.
 183
 184 **/
 185 UINT32
 186 EFIAPI
 187 IoRead32 (
 188   IN      UINTN                     Port
 189   )
 190 {
 191   UINT32                            Value;
 192
 193   ASSERT ((Port & 3) == 0);
 194   _ReadWriteBarrier ();
 195   Value = _inpd ((UINT16)Port);
 196   _ReadWriteBarrier ();
 197   return Value;
 198 }
 199
 200 /**
 201   Writes a 32-bit I/O port.
 202
 203   Writes the 32-bit I/O port specified by Port with the value specified by Value
 204   and returns Value. This function must guarantee that all I/O read and write
 205   operations are serialized.
 206
 207   If 32-bit I/O port operations are not supported, then ASSERT().
 208   If Port is not aligned on a 32-bit boundary, then ASSERT().
 209
 210   @param  Port  The I/O port to write.
 211   @param  Value The value to write to the I/O port.
 212
 213   @return The value written the I/O port.
 214
 215 **/
 216 UINT32
 217 EFIAPI
 218 IoWrite32 (
 219   IN      UINTN                     Port,
 220   IN      UINT32                    Value
 221   )
 222 {
 223   ASSERT ((Port & 3) == 0);
 224   _ReadWriteBarrier ();
 225   _outpd ((UINT16)Port, Value);
 226   _ReadWriteBarrier ();
 227   return Value;
 228 }