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/*++
Copyright (c) 2006, Intel Corporation
All rights reserved. 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.
Module Name:
Crc32.c
Abstract:
CalculateCrc32 Boot Services as defined in DXE CIS.
This Boot Services is in the Runtime Driver because this service is
also required by SetVirtualAddressMap() when the EFI System Table and
EFI Runtime Services Table are converted from physical address to
virtual addresses. This requires that the 32-bit CRC be recomputed.
Revision History:
--*/
#include "Runtime.h"
UINT32 mCrcTable[256];
EFI_STATUS
EFIAPI
RuntimeDriverCalculateCrc32 (
IN VOID *Data,
IN UINTN DataSize,
OUT UINT32 *CrcOut
)
/*++
Routine Description:
Calculate CRC32 for target data
Arguments:
Data - The target data.
DataSize - The target data size.
CrcOut - The CRC32 for target data.
Returns:
EFI_SUCCESS - The CRC32 for target data is calculated successfully.
EFI_INVALID_PARAMETER - Some parameter is not valid, so the CRC32 is not
calculated.
--*/
{
UINT32 Crc;
UINTN Index;
UINT8 *Ptr;
if (Data == NULL || DataSize == 0 || CrcOut == NULL) {
return EFI_INVALID_PARAMETER;
}
Crc = 0xffffffff;
for (Index = 0, Ptr = Data; Index < DataSize; Index++, Ptr++) {
Crc = (Crc >> 8) ^ mCrcTable[(UINT8) Crc ^ *Ptr];
}
*CrcOut = Crc ^ 0xffffffff;
return EFI_SUCCESS;
}
STATIC
UINT32
ReverseBits (
UINT32 Value
)
/*++
Routine Description:
Reverse bits for 32bit data.
Arguments:
Value - the data to be reversed.
Returns:
UINT32 data reversed.
--*/
{
UINTN Index;
UINT32 NewValue;
NewValue = 0;
for (Index = 0; Index < 32; Index++) {
if (Value & (1 << Index)) {
NewValue = NewValue | (1 << (31 - Index));
}
}
return NewValue;
}
VOID
RuntimeDriverInitializeCrc32Table (
VOID
)
/*++
Routine Description:
Initialize CRC32 table.
Arguments:
None.
Returns:
None.
--*/
{
UINTN TableEntry;
UINTN Index;
UINT32 Value;
for (TableEntry = 0; TableEntry < 256; TableEntry++) {
Value = ReverseBits ((UINT32) TableEntry);
for (Index = 0; Index < 8; Index++) {
if (Value & 0x80000000) {
Value = (Value << 1) ^ 0x04c11db7;
} else {
Value = Value << 1;
}
}
mCrcTable[TableEntry] = ReverseBits (Value);
}
}
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