mirror of https://github.com/acidanthera/audk.git
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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