MdePkg/Library/BaseIoLibIntrinsic/IoLibGcc.c

   1 /** @file
   2   I/O Library. This file has compiler specifics for GCC as there is no
   3   ANSI C standard for doing IO.
   4
   5   GCC - uses EFIAPI assembler. __asm__ calls GAS. __volatile__ makes sure the
   6   compiler puts the assembler in this exact location. The complex GNUC
   7   operations are not optimzed. It would be possible to also write these
   8   with EFIAPI assembler.
   9
  10   We don't advocate putting compiler specifics in libraries or drivers but there
  11   is no other way to make this work.
  12
  13   Copyright (c) 2006, Intel Corporation<BR>
  14   All rights reserved. This program and the accompanying materials
  15   are licensed and made available under the terms and conditions of the BSD License
  16   which accompanies this distribution.  The full text of the license may be found at
  17   http://opensource.org/licenses/bsd-license.php
  18
  19   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  20   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  21
  22   Module Name:  IoLibGcc.c
  23
  24 **/
  25
  26 #ifdef __GNUC__
  27
  28 /**
  29   Reads an 8-bit I/O port.
  30
  31   Reads the 8-bit I/O port specified by Port. The 8-bit read value is returned.
  32   This function must guarantee that all I/O read and write operations are
  33   serialized.
  34
  35   If 8-bit I/O port operations are not supported, then ASSERT().
  36
  37   @param  Port  The I/O port to read.
  38
  39   @return The value read.
  40
  41 **/
  42 __inline__
  43 UINT8
  44 EFIAPI
  45 IoRead8 (
  46   IN      UINTN                     Port
  47   )
  48 {
  49   UINT8   Data;
  50
  51   __asm__ __volatile__ ("inb %w1,%b0" : "=a" (Data) : "d" ((UINT16)Port));
  52   return Data;
  53 }
  54
  55 /**
  56   Writes an 8-bit I/O port.
  57
  58   Writes the 8-bit I/O port specified by Port with the value specified by Value
  59   and returns Value. This function must guarantee that all I/O read and write
  60   operations are serialized.
  61
  62   If 8-bit I/O port operations are not supported, then ASSERT().
  63
  64   @param  Port  The I/O port to write.
  65   @param  Value The value to write to the I/O port.
  66
  67   @return The value written the I/O port.
  68
  69 **/
  70 __inline__
  71 UINT8
  72 EFIAPI
  73 IoWrite8 (
  74   IN      UINTN                     Port,
  75   IN      UINT8                     Value
  76   )
  77 {
  78   __asm__ __volatile__ ("outb %b0,%w1" : : "a" (Value), "d" ((UINT16)Port));
  79   return Value;;
  80 }
  81
  82 /**
  83   Reads a 16-bit I/O port.
  84
  85   Reads the 16-bit I/O port specified by Port. The 16-bit read value is returned.
  86   This function must guarantee that all I/O read and write operations are
  87   serialized.
  88
  89   If 16-bit I/O port operations are not supported, then ASSERT().
  90
  91   @param  Port  The I/O port to read.
  92
  93   @return The value read.
  94
  95 **/
  96 __inline__
  97 UINT16
  98 EFIAPI
  99 IoRead16 (
 100   IN      UINTN                     Port
 101   )
 102 {
 103   UINT16   Data;
 104
 105   ASSERT ((Port & 1) == 0);
 106   __asm__ __volatile__ ("inw %w1,%w0" : "=a" (Data) : "d" ((UINT16)Port));
 107   return Data;
 108 }
 109
 110 /**
 111   Writes a 16-bit I/O port.
 112
 113   Writes the 16-bit I/O port specified by Port with the value specified by Value
 114   and returns Value. This function must guarantee that all I/O read and write
 115   operations are serialized.
 116
 117   If 16-bit I/O port operations are not supported, then ASSERT().
 118
 119   @param  Port  The I/O port to write.
 120   @param  Value The value to write to the I/O port.
 121
 122   @return The value written the I/O port.
 123
 124 **/
 125 __inline__
 126 UINT16
 127 EFIAPI
 128 IoWrite16 (
 129   IN      UINTN                     Port,
 130   IN      UINT16                    Value
 131   )
 132 {
 133   ASSERT ((Port & 1) == 0);
 134   __asm__ __volatile__ ("outw %w0,%w1" : : "a" (Value), "d" ((UINT16)Port));
 135   return Value;;
 136 }
 137
 138 /**
 139   Reads a 32-bit I/O port.
 140
 141   Reads the 32-bit I/O port specified by Port. The 32-bit read value is returned.
 142   This function must guarantee that all I/O read and write operations are
 143   serialized.
 144
 145   If 32-bit I/O port operations are not supported, then ASSERT().
 146
 147   @param  Port  The I/O port to read.
 148
 149   @return The value read.
 150
 151 **/
 152 __inline__
 153 UINT32
 154 EFIAPI
 155 IoRead32 (
 156   IN      UINTN                     Port
 157   )
 158 {
 159   UINT32   Data;
 160
 161   ASSERT ((Port & 3) == 0);
 162   __asm__ __volatile__ ("inl %w1,%0" : "=a" (Data) : "d" ((UINT16)Port));
 163   return Data;
 164 }
 165
 166 /**
 167   Writes a 32-bit I/O port.
 168
 169   Writes the 32-bit I/O port specified by Port with the value specified by Value
 170   and returns Value. This function must guarantee that all I/O read and write
 171   operations are serialized.
 172
 173   If 32-bit I/O port operations are not supported, then ASSERT().
 174
 175   @param  Port  The I/O port to write.
 176   @param  Value The value to write to the I/O port.
 177
 178   @return The value written the I/O port.
 179
 180 **/
 181 __inline__
 182 UINT32
 183 EFIAPI
 184 IoWrite32 (
 185   IN      UINTN                     Port,
 186   IN      UINT32  Value
 187   )
 188 {
 189   ASSERT ((Port & 3) == 0);
 190   __asm__ __volatile__ ("outl %0,%w1" : : "a" (Value), "d" ((UINT16)Port));
 191   return Value;
 192 }
 193
 194 #endif