git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@5758 6f19259b-4bc3-4df7-8a09-765794883524
		
			
				
	
	
		
			115 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			115 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/** @file
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  CalculateCrc32 Boot Services as defined in DXE CIS.
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  This Boot Services is in the Runtime Driver because this service is
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  also required by SetVirtualAddressMap() when the EFI System Table and
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  EFI Runtime Services Table are converted from physical address to
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  virtual addresses.	This requires that the 32-bit CRC be recomputed.
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Copyright (c) 2006, Intel Corporation. <BR>
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All rights reserved. This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution.  The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include <Uefi.h>
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UINT32  mCrcTable[256];
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/**
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  Calculate CRC32 for target data.
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  @param  Data                  The target data.
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  @param  DataSize              The target data size.
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  @param  CrcOut                The CRC32 for target data.
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  @retval EFI_SUCCESS           The CRC32 for target data is calculated successfully.
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  @retval EFI_INVALID_PARAMETER Some parameter is not valid, so the CRC32 is not
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                                calculated.
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**/
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EFI_STATUS
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EFIAPI
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RuntimeDriverCalculateCrc32 (
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  IN  VOID    *Data,
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  IN  UINTN   DataSize,
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  OUT UINT32  *CrcOut
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  )
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{
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  UINT32  Crc;
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  UINTN   Index;
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  UINT8   *Ptr;
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  if (Data == NULL || DataSize == 0 || CrcOut == NULL) {
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    return EFI_INVALID_PARAMETER;
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  }
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  Crc = 0xffffffff;
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  for (Index = 0, Ptr = Data; Index < DataSize; Index++, Ptr++) {
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    Crc = (Crc >> 8) ^ mCrcTable[(UINT8) Crc ^ *Ptr];
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  }
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  *CrcOut = Crc ^ 0xffffffff;
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  return EFI_SUCCESS;
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}
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/**
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  Reverse bits for 32bit data.
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  This is a internal function.
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  @param  Value                 The data to be reversed.
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  @return                       Data reversed.
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**/
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UINT32
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ReverseBits (
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  UINT32  Value
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  )
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{
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  UINTN   Index;
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  UINT32  NewValue;
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  NewValue = 0;
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  for (Index = 0; Index < 32; Index++) {
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    if ((Value & (1 << Index)) != 0) {
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      NewValue = NewValue | (1 << (31 - Index));
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    }
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  }
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  return NewValue;
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}
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/**
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  Initialize CRC32 table.
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**/
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VOID
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RuntimeDriverInitializeCrc32Table (
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  VOID
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  )
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{
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  UINTN   TableEntry;
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  UINTN   Index;
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  UINT32  Value;
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  for (TableEntry = 0; TableEntry < 256; TableEntry++) {
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    Value = ReverseBits ((UINT32) TableEntry);
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    for (Index = 0; Index < 8; Index++) {
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      if ((Value & 0x80000000) != 0) {
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        Value = (Value << 1) ^ 0x04c11db7;
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      } else {
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        Value = Value << 1;
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      }
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    }
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    mCrcTable[TableEntry] = ReverseBits (Value);
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  }
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}
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