/* *  Fast C2P (Chunky-to-Planar) Conversion * *  Copyright (C) 2003-2008 Geert Uytterhoeven * *  NOTES: *    - This code was inspired by Scout's C2P tutorial *    - It assumes to run on a big endian system * *  This file is subject to the terms and conditions of the GNU General Public *  License. See the file COPYING in the main directory of this archive *  for more details. */ #include <linux/build_bug.h>      /*     *  Basic transpose step     */ static inline void _transp(u32 d[], unsigned int i1, unsigned int i2,			   unsigned int shift, u32 mask){	u32 t = (d[i1] ^ (d[i2] >> shift)) & mask; 	d[i1] ^= t;	d[i2] ^= t << shift;}  static __always_inline u32 get_mask(unsigned int n){	switch (n) {	case 1:		return 0x55555555; 	case 2:		return 0x33333333; 	case 4:		return 0x0f0f0f0f; 	case 8:		return 0x00ff00ff; 	case 16:		return 0x0000ffff;	} 	BUILD_BUG();	return 0;}      /*     *  Transpose operations on 8 32-bit words     */ static __always_inline void transp8(u32 d[], unsigned int n, unsigned int m){	u32 mask = get_mask(n); 	switch (m) {	case 1:		/* First n x 1 block */		_transp(d, 0, 1, n, mask);		/* Second n x 1 block */		_transp(d, 2, 3, n, mask);		/* Third n x 1 block */		_transp(d, 4, 5, n, mask);		/* Fourth n x 1 block */		_transp(d, 6, 7, n, mask);		return; 	case 2:		/* First n x 2 block */		_transp(d, 0, 2, n, mask);		_transp(d, 1, 3, n, mask);		/* Second n x 2 block */		_transp(d, 4, 6, n, mask);		_transp(d, 5, 7, n, mask);		return; 	case 4:		/* Single n x 4 block */		_transp(d, 0, 4, n, mask);		_transp(d, 1, 5, n, mask);		_transp(d, 2, 6, n, mask);		_transp(d, 3, 7, n, mask);		return;	} 	BUILD_BUG();}      /*     *  Transpose operations on 4 32-bit words     */ static __always_inline void transp4(u32 d[], unsigned int n, unsigned int m){	u32 mask = get_mask(n); 	switch (m) {	case 1:		/* First n x 1 block */		_transp(d, 0, 1, n, mask);		/* Second n x 1 block */		_transp(d, 2, 3, n, mask);		return; 	case 2:		/* Single n x 2 block */		_transp(d, 0, 2, n, mask);		_transp(d, 1, 3, n, mask);		return;	} 	BUILD_BUG();}      /*     *  Transpose operations on 4 32-bit words (reverse order)     */ static __always_inline void transp4x(u32 d[], unsigned int n, unsigned int m){	u32 mask = get_mask(n); 	switch (m) {	case 2:		/* Single n x 2 block */		_transp(d, 2, 0, n, mask);		_transp(d, 3, 1, n, mask);		return;	} 	BUILD_BUG();}      /*     *  Compose two values, using a bitmask as decision value     *  This is equivalent to (a & mask) | (b & ~mask)     */ static inline u32 comp(u32 a, u32 b, u32 mask){	return ((a ^ b) & mask) ^ b;}