1. 根目录:
2. drivers
3. staging
4. rtl8192u
5. ieee80211
6. EndianFree.h

#ifndef __INC_ENDIANFREE_H
#define __INC_ENDIANFREE_H

/*
 *	Call endian free function when
 *		1. Read/write packet content.
 *		2. Before write integer to IO.
 *		3. After read integer from IO.
 */

#define __MACHINE_LITTLE_ENDIAN 1234    /* LSB first: i386, vax */
#define __MACHINE_BIG_ENDIAN    4321    /* MSB first: 68000, ibm, net, ppc */

#define BYTE_ORDER __MACHINE_LITTLE_ENDIAN

#if BYTE_ORDER == __MACHINE_LITTLE_ENDIAN
// Convert data
#define EF1Byte(_val)				((u8)(_val))
#define EF2Byte(_val)				((u16)(_val))
#define EF4Byte(_val)				((u32)(_val))

#else
// Convert data
#define EF1Byte(_val)				((u8)(_val))
#define EF2Byte(_val)				(((((u16)(_val))&0x00ff)<<8)|((((u16)(_val))&0xff00)>>8))
#define EF4Byte(_val)				(((((u32)(_val))&0x000000ff)<<24)|\
						((((u32)(_val))&0x0000ff00)<<8)|\
						((((u32)(_val))&0x00ff0000)>>8)|\
						((((u32)(_val))&0xff000000)>>24))
#endif

// Read data from memory
#define ReadEF1Byte(_ptr)		EF1Byte(*((u8 *)(_ptr)))
#define ReadEF2Byte(_ptr)		EF2Byte(*((u16 *)(_ptr)))
#define ReadEF4Byte(_ptr)		EF4Byte(*((u32 *)(_ptr)))

// Write data to memory
#define WriteEF1Byte(_ptr, _val)	(*((u8 *)(_ptr)))=EF1Byte(_val)
#define WriteEF2Byte(_ptr, _val)	(*((u16 *)(_ptr)))=EF2Byte(_val)
#define WriteEF4Byte(_ptr, _val)	(*((u32 *)(_ptr)))=EF4Byte(_val)
// Convert Host system specific byte ording (litten or big endia) to Network byte ording (big endian).
// 2006.05.07, by rcnjko.
#if BYTE_ORDER == __MACHINE_LITTLE_ENDIAN
#define H2N1BYTE(_val)	((u8)(_val))
#define H2N2BYTE(_val)	(((((u16)(_val))&0x00ff)<<8)|\
			((((u16)(_val))&0xff00)>>8))
#define H2N4BYTE(_val)	(((((u32)(_val))&0x000000ff)<<24)|\
			((((u32)(_val))&0x0000ff00)<<8)	|\
			((((u32)(_val))&0x00ff0000)>>8)	|\
			((((u32)(_val))&0xff000000)>>24))
#else
#define H2N1BYTE(_val)			((u8)(_val))
#define H2N2BYTE(_val)			((u16)(_val))
#define H2N4BYTE(_val)			((u32)(_val))
#endif

// Convert from Network byte ording (big endian) to Host system specific byte ording (litten or big endia).
// 2006.05.07, by rcnjko.
#if BYTE_ORDER == __MACHINE_LITTLE_ENDIAN
#define N2H1BYTE(_val)	((u8)(_val))
#define N2H2BYTE(_val)	(((((u16)(_val))&0x00ff)<<8)|\
			((((u16)(_val))&0xff00)>>8))
#define N2H4BYTE(_val)	(((((u32)(_val))&0x000000ff)<<24)|\
			((((u32)(_val))&0x0000ff00)<<8)	|\
			((((u32)(_val))&0x00ff0000)>>8)	|\
			((((u32)(_val))&0xff000000)>>24))
#else
#define N2H1BYTE(_val)			((u8)(_val))
#define N2H2BYTE(_val)			((u16)(_val))
#define N2H4BYTE(_val)			((u32)(_val))
#endif

//
//	Example:
//		BIT_LEN_MASK_32(0) => 0x00000000
//		BIT_LEN_MASK_32(1) => 0x00000001
//		BIT_LEN_MASK_32(2) => 0x00000003
//		BIT_LEN_MASK_32(32) => 0xFFFFFFFF
//
#define BIT_LEN_MASK_32(__BitLen) (0xFFFFFFFF >> (32 - (__BitLen)))
//
//	Example:
//		BIT_OFFSET_LEN_MASK_32(0, 2) => 0x00000003
//		BIT_OFFSET_LEN_MASK_32(16, 2) => 0x00030000
//
#define BIT_OFFSET_LEN_MASK_32(__BitOffset, __BitLen) (BIT_LEN_MASK_32(__BitLen) << (__BitOffset))

//
//	Description:
//		Return 4-byte value in host byte ordering from
//		4-byte pointer in litten-endian system.
//
#define LE_P4BYTE_TO_HOST_4BYTE(__pStart) (EF4Byte(*((u32 *)(__pStart))))

//
//	Description:
//		Translate subfield (continuous bits in little-endian) of 4-byte value in litten byte to
//		4-byte value in host byte ordering.
//
#define LE_BITS_TO_4BYTE(__pStart, __BitOffset, __BitLen) \
	( \
	  ( LE_P4BYTE_TO_HOST_4BYTE(__pStart) >> (__BitOffset) ) \
	  & \
	  BIT_LEN_MASK_32(__BitLen) \
	)

//
//	Description:
//		Mask subfield (continuous bits in little-endian) of 4-byte value in litten byte oredering
//		and return the result in 4-byte value in host byte ordering.
//
#define LE_BITS_CLEARED_TO_4BYTE(__pStart, __BitOffset, __BitLen) \
	( \
	  LE_P4BYTE_TO_HOST_4BYTE(__pStart) \
	  & \
	  ( ~BIT_OFFSET_LEN_MASK_32(__BitOffset, __BitLen) ) \
	)

//
//	Description:
//		Set subfield of little-endian 4-byte value to specified value.
//
#define SET_BITS_TO_LE_4BYTE(__pStart, __BitOffset, __BitLen, __Value) \
	*((u32 *)(__pStart)) = \
	EF4Byte( \
	LE_BITS_CLEARED_TO_4BYTE(__pStart, __BitOffset, __BitLen) \
	| \
	( (((u32)__Value) & BIT_LEN_MASK_32(__BitLen)) << (__BitOffset) ) \
       );


#define BIT_LEN_MASK_16(__BitLen) \
	(0xFFFF >> (16 - (__BitLen)))

#define BIT_OFFSET_LEN_MASK_16(__BitOffset, __BitLen) \
	(BIT_LEN_MASK_16(__BitLen) << (__BitOffset))

#define LE_P2BYTE_TO_HOST_2BYTE(__pStart) \
	(EF2Byte(*((u16 *)(__pStart))))

#define LE_BITS_TO_2BYTE(__pStart, __BitOffset, __BitLen) \
	( \
	  ( LE_P2BYTE_TO_HOST_2BYTE(__pStart) >> (__BitOffset) ) \
	  & \
	  BIT_LEN_MASK_16(__BitLen) \
	)

#define LE_BITS_CLEARED_TO_2BYTE(__pStart, __BitOffset, __BitLen) \
	( \
	  LE_P2BYTE_TO_HOST_2BYTE(__pStart) \
	  & \
	  ( ~BIT_OFFSET_LEN_MASK_16(__BitOffset, __BitLen) ) \
	)

#define SET_BITS_TO_LE_2BYTE(__pStart, __BitOffset, __BitLen, __Value) \
	*((u16 *)(__pStart)) = \
	EF2Byte( \
		LE_BITS_CLEARED_TO_2BYTE(__pStart, __BitOffset, __BitLen) \
		| \
		( (((u16)__Value) & BIT_LEN_MASK_16(__BitLen)) << (__BitOffset) ) \
       );

#define BIT_LEN_MASK_8(__BitLen) \
	(0xFF >> (8 - (__BitLen)))

#define BIT_OFFSET_LEN_MASK_8(__BitOffset, __BitLen) \
	(BIT_LEN_MASK_8(__BitLen) << (__BitOffset))

#define LE_P1BYTE_TO_HOST_1BYTE(__pStart) \
	(EF1Byte(*((u8 *)(__pStart))))

#define LE_BITS_TO_1BYTE(__pStart, __BitOffset, __BitLen) \
	( \
	  ( LE_P1BYTE_TO_HOST_1BYTE(__pStart) >> (__BitOffset) ) \
	  & \
	  BIT_LEN_MASK_8(__BitLen) \
	)

#define LE_BITS_CLEARED_TO_1BYTE(__pStart, __BitOffset, __BitLen) \
	( \
	  LE_P1BYTE_TO_HOST_1BYTE(__pStart) \
	  & \
	  ( ~BIT_OFFSET_LEN_MASK_8(__BitOffset, __BitLen) ) \
	)

#define SET_BITS_TO_LE_1BYTE(__pStart, __BitOffset, __BitLen, __Value) \
	*((u8 *)(__pStart)) = \
	EF1Byte( \
		LE_BITS_CLEARED_TO_1BYTE(__pStart, __BitOffset, __BitLen) \
		| \
		( (((u8)__Value) & BIT_LEN_MASK_8(__BitLen)) << (__BitOffset) ) \
       );

#endif // #ifndef __INC_ENDIANFREE_H