/** @file | |
Unaligned access functions of BaseLib for ARM. | |
volatile was added to work around optimization issues. | |
Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR> | |
Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR> | |
SPDX-License-Identifier: BSD-2-Clause-Patent | |
**/ | |
#include "BaseLibInternals.h" | |
/** | |
Reads a 16-bit value from memory that may be unaligned. | |
This function returns the 16-bit value pointed to by Buffer. The function | |
guarantees that the read operation does not produce an alignment fault. | |
If the Buffer is NULL, then ASSERT(). | |
@param Buffer The pointer to a 16-bit value that may be unaligned. | |
@return The 16-bit value read from Buffer. | |
**/ | |
UINT16 | |
EFIAPI | |
ReadUnaligned16 ( | |
IN CONST UINT16 *Buffer | |
) | |
{ | |
volatile UINT8 LowerByte; | |
volatile UINT8 HigherByte; | |
ASSERT (Buffer != NULL); | |
LowerByte = ((UINT8 *)Buffer)[0]; | |
HigherByte = ((UINT8 *)Buffer)[1]; | |
return (UINT16)(LowerByte | (HigherByte << 8)); | |
} | |
/** | |
Writes a 16-bit value to memory that may be unaligned. | |
This function writes the 16-bit value specified by Value to Buffer. Value is | |
returned. The function guarantees that the write operation does not produce | |
an alignment fault. | |
If the Buffer is NULL, then ASSERT(). | |
@param Buffer The pointer to a 16-bit value that may be unaligned. | |
@param Value 16-bit value to write to Buffer. | |
@return The 16-bit value to write to Buffer. | |
**/ | |
UINT16 | |
EFIAPI | |
WriteUnaligned16 ( | |
OUT UINT16 *Buffer, | |
IN UINT16 Value | |
) | |
{ | |
ASSERT (Buffer != NULL); | |
((volatile UINT8 *)Buffer)[0] = (UINT8)Value; | |
((volatile UINT8 *)Buffer)[1] = (UINT8)(Value >> 8); | |
return Value; | |
} | |
/** | |
Reads a 24-bit value from memory that may be unaligned. | |
This function returns the 24-bit value pointed to by Buffer. The function | |
guarantees that the read operation does not produce an alignment fault. | |
If the Buffer is NULL, then ASSERT(). | |
@param Buffer The pointer to a 24-bit value that may be unaligned. | |
@return The 24-bit value read from Buffer. | |
**/ | |
UINT32 | |
EFIAPI | |
ReadUnaligned24 ( | |
IN CONST UINT32 *Buffer | |
) | |
{ | |
ASSERT (Buffer != NULL); | |
return (UINT32)( | |
ReadUnaligned16 ((UINT16 *)Buffer) | | |
(((UINT8 *)Buffer)[2] << 16) | |
); | |
} | |
/** | |
Writes a 24-bit value to memory that may be unaligned. | |
This function writes the 24-bit value specified by Value to Buffer. Value is | |
returned. The function guarantees that the write operation does not produce | |
an alignment fault. | |
If the Buffer is NULL, then ASSERT(). | |
@param Buffer The pointer to a 24-bit value that may be unaligned. | |
@param Value 24-bit value to write to Buffer. | |
@return The 24-bit value to write to Buffer. | |
**/ | |
UINT32 | |
EFIAPI | |
WriteUnaligned24 ( | |
OUT UINT32 *Buffer, | |
IN UINT32 Value | |
) | |
{ | |
ASSERT (Buffer != NULL); | |
WriteUnaligned16 ((UINT16 *)Buffer, (UINT16)Value); | |
*(UINT8 *)((UINT16 *)Buffer + 1) = (UINT8)(Value >> 16); | |
return Value; | |
} | |
/** | |
Reads a 32-bit value from memory that may be unaligned. | |
This function returns the 32-bit value pointed to by Buffer. The function | |
guarantees that the read operation does not produce an alignment fault. | |
If the Buffer is NULL, then ASSERT(). | |
@param Buffer The pointer to a 32-bit value that may be unaligned. | |
@return The 32-bit value read from Buffer. | |
**/ | |
UINT32 | |
EFIAPI | |
ReadUnaligned32 ( | |
IN CONST UINT32 *Buffer | |
) | |
{ | |
UINT16 LowerBytes; | |
UINT16 HigherBytes; | |
ASSERT (Buffer != NULL); | |
LowerBytes = ReadUnaligned16 ((UINT16 *)Buffer); | |
HigherBytes = ReadUnaligned16 ((UINT16 *)Buffer + 1); | |
return (UINT32)(LowerBytes | (HigherBytes << 16)); | |
} | |
/** | |
Writes a 32-bit value to memory that may be unaligned. | |
This function writes the 32-bit value specified by Value to Buffer. Value is | |
returned. The function guarantees that the write operation does not produce | |
an alignment fault. | |
If the Buffer is NULL, then ASSERT(). | |
@param Buffer The pointer to a 32-bit value that may be unaligned. | |
@param Value 32-bit value to write to Buffer. | |
@return The 32-bit value to write to Buffer. | |
**/ | |
UINT32 | |
EFIAPI | |
WriteUnaligned32 ( | |
OUT UINT32 *Buffer, | |
IN UINT32 Value | |
) | |
{ | |
ASSERT (Buffer != NULL); | |
WriteUnaligned16 ((UINT16 *)Buffer, (UINT16)Value); | |
WriteUnaligned16 ((UINT16 *)Buffer + 1, (UINT16)(Value >> 16)); | |
return Value; | |
} | |
/** | |
Reads a 64-bit value from memory that may be unaligned. | |
This function returns the 64-bit value pointed to by Buffer. The function | |
guarantees that the read operation does not produce an alignment fault. | |
If the Buffer is NULL, then ASSERT(). | |
@param Buffer The pointer to a 64-bit value that may be unaligned. | |
@return The 64-bit value read from Buffer. | |
**/ | |
UINT64 | |
EFIAPI | |
ReadUnaligned64 ( | |
IN CONST UINT64 *Buffer | |
) | |
{ | |
UINT32 LowerBytes; | |
UINT32 HigherBytes; | |
ASSERT (Buffer != NULL); | |
LowerBytes = ReadUnaligned32 ((UINT32 *)Buffer); | |
HigherBytes = ReadUnaligned32 ((UINT32 *)Buffer + 1); | |
return (UINT64)(LowerBytes | LShiftU64 (HigherBytes, 32)); | |
} | |
/** | |
Writes a 64-bit value to memory that may be unaligned. | |
This function writes the 64-bit value specified by Value to Buffer. Value is | |
returned. The function guarantees that the write operation does not produce | |
an alignment fault. | |
If the Buffer is NULL, then ASSERT(). | |
@param Buffer The pointer to a 64-bit value that may be unaligned. | |
@param Value 64-bit value to write to Buffer. | |
@return The 64-bit value to write to Buffer. | |
**/ | |
UINT64 | |
EFIAPI | |
WriteUnaligned64 ( | |
OUT UINT64 *Buffer, | |
IN UINT64 Value | |
) | |
{ | |
ASSERT (Buffer != NULL); | |
WriteUnaligned32 ((UINT32 *)Buffer, (UINT32)Value); | |
WriteUnaligned32 ((UINT32 *)Buffer + 1, (UINT32)RShiftU64 (Value, 32)); | |
return Value; | |
} |