MdeModulePkg/Core/RuntimeDxe/Crc32.c

   1 /** @file
   2   CalculateCrc32 Boot Services as defined in DXE CIS.
   3
   4 Copyright (c) 2006, Intel Corporation. <BR>
   5 All rights reserved. This program and the accompanying materials
   6 are licensed and made available under the terms and conditions of the BSD License
   7 which accompanies this distribution.  The full text of the license may be found at
   8 http://opensource.org/licenses/bsd-license.php
   9
  10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 Module Name:
  14
  15   Crc32.c
  16
  17 Abstract:
  18
  19   This Boot Services is in the Runtime Driver because this service is
  20   also required by SetVirtualAddressMap() when the EFI System Table and
  21   EFI Runtime Services Table are converted from physical address to
  22   virtual addresses.  This requires that the 32-bit CRC be recomputed.
  23
  24 **/
  25
  26
  27 #include <PiDxe.h>
  28
  29 UINT32  mCrcTable[256];
  30
  31 /**
  32   Calculate CRC32 for target data.
  33
  34   @param  Data                  The target data.
  35   @param  DataSize              The target data size.
  36   @param  CrcOut                The CRC32 for target data.
  37
  38   @retval EFI_SUCCESS           The CRC32 for target data is calculated successfully.
  39   @retval EFI_INVALID_PARAMETER Some parameter is not valid, so the CRC32 is not
  40                                 calculated.
  41
  42 **/
  43 EFI_STATUS
  44 EFIAPI
  45 RuntimeDriverCalculateCrc32 (
  46   IN  VOID    *Data,
  47   IN  UINTN   DataSize,
  48   OUT UINT32  *CrcOut
  49   )
  50 {
  51   UINT32  Crc;
  52   UINTN   Index;
  53   UINT8   *Ptr;
  54
  55   if (Data == NULL || DataSize == 0 || CrcOut == NULL) {
  56     return EFI_INVALID_PARAMETER;
  57   }
  58
  59   Crc = 0xffffffff;
  60   for (Index = 0, Ptr = Data; Index < DataSize; Index++, Ptr++) {
  61     Crc = (Crc >> 8) ^ mCrcTable[(UINT8) Crc ^ *Ptr];
  62   }
  63
  64   *CrcOut = Crc ^ 0xffffffff;
  65   return EFI_SUCCESS;
  66 }
  67
  68
  69 /**
  70   Reverse bits for 32bit data.
  71   This is a internal function.
  72
  73   @param  Value                 The data to be reversed.
  74
  75   @return                       Data reversed.
  76
  77 **/
  78 UINT32
  79 ReverseBits (
  80   UINT32  Value
  81   )
  82 {
  83   UINTN   Index;
  84   UINT32  NewValue;
  85
  86   NewValue = 0;
  87   for (Index = 0; Index < 32; Index++) {
  88     if ((Value & (1 << Index)) != 0) {
  89       NewValue = NewValue | (1 << (31 - Index));
  90     }
  91   }
  92
  93   return NewValue;
  94 }
  95
  96 /**
  97   Initialize CRC32 table.
  98 **/
  99 VOID
 100 RuntimeDriverInitializeCrc32Table (
 101   VOID
 102   )
 103 {
 104   UINTN   TableEntry;
 105   UINTN   Index;
 106   UINT32  Value;
 107
 108   for (TableEntry = 0; TableEntry < 256; TableEntry++) {
 109     Value = ReverseBits ((UINT32) TableEntry);
 110     for (Index = 0; Index < 8; Index++) {
 111       if ((Value & 0x80000000) != 0) {
 112         Value = (Value << 1) ^ 0x04c11db7;
 113       } else {
 114         Value = Value << 1;
 115       }
 116     }
 117
 118     mCrcTable[TableEntry] = ReverseBits (Value);
 119   }
 120 }