1/*
2 *  Fast C2P (Chunky-to-Planar) Conversion
3 *
4 *  Copyright (C) 2003-2008 Geert Uytterhoeven
5 *
6 *  NOTES:
7 *    - This code was inspired by Scout's C2P tutorial
8 *    - It assumes to run on a big endian system
9 *
10 *  This file is subject to the terms and conditions of the GNU General Public
11 *  License. See the file COPYING in the main directory of this archive
12 *  for more details.
13 */
14
15
16    /*
17     *  Basic transpose step
18     */
19
20static inline void _transp(u32 d[], unsigned int i1, unsigned int i2,
21			   unsigned int shift, u32 mask)
22{
23	u32 t = (d[i1] ^ (d[i2] >> shift)) & mask;
24
25	d[i1] ^= t;
26	d[i2] ^= t << shift;
27}
28
29
30extern void c2p_unsupported(void);
31
32static inline u32 get_mask(unsigned int n)
33{
34	switch (n) {
35	case 1:
36		return 0x55555555;
37
38	case 2:
39		return 0x33333333;
40
41	case 4:
42		return 0x0f0f0f0f;
43
44	case 8:
45		return 0x00ff00ff;
46
47	case 16:
48		return 0x0000ffff;
49	}
50
51	c2p_unsupported();
52	return 0;
53}
54
55
56    /*
57     *  Transpose operations on 8 32-bit words
58     */
59
60static inline void transp8(u32 d[], unsigned int n, unsigned int m)
61{
62	u32 mask = get_mask(n);
63
64	switch (m) {
65	case 1:
66		/* First n x 1 block */
67		_transp(d, 0, 1, n, mask);
68		/* Second n x 1 block */
69		_transp(d, 2, 3, n, mask);
70		/* Third n x 1 block */
71		_transp(d, 4, 5, n, mask);
72		/* Fourth n x 1 block */
73		_transp(d, 6, 7, n, mask);
74		return;
75
76	case 2:
77		/* First n x 2 block */
78		_transp(d, 0, 2, n, mask);
79		_transp(d, 1, 3, n, mask);
80		/* Second n x 2 block */
81		_transp(d, 4, 6, n, mask);
82		_transp(d, 5, 7, n, mask);
83		return;
84
85	case 4:
86		/* Single n x 4 block */
87		_transp(d, 0, 4, n, mask);
88		_transp(d, 1, 5, n, mask);
89		_transp(d, 2, 6, n, mask);
90		_transp(d, 3, 7, n, mask);
91		return;
92	}
93
94	c2p_unsupported();
95}
96
97
98    /*
99     *  Transpose operations on 4 32-bit words
100     */
101
102static inline void transp4(u32 d[], unsigned int n, unsigned int m)
103{
104	u32 mask = get_mask(n);
105
106	switch (m) {
107	case 1:
108		/* First n x 1 block */
109		_transp(d, 0, 1, n, mask);
110		/* Second n x 1 block */
111		_transp(d, 2, 3, n, mask);
112		return;
113
114	case 2:
115		/* Single n x 2 block */
116		_transp(d, 0, 2, n, mask);
117		_transp(d, 1, 3, n, mask);
118		return;
119	}
120
121	c2p_unsupported();
122}
123
124
125    /*
126     *  Transpose operations on 4 32-bit words (reverse order)
127     */
128
129static inline void transp4x(u32 d[], unsigned int n, unsigned int m)
130{
131	u32 mask = get_mask(n);
132
133	switch (m) {
134	case 2:
135		/* Single n x 2 block */
136		_transp(d, 2, 0, n, mask);
137		_transp(d, 3, 1, n, mask);
138		return;
139	}
140
141	c2p_unsupported();
142}
143
144
145    /*
146     *  Compose two values, using a bitmask as decision value
147     *  This is equivalent to (a & mask) | (b & ~mask)
148     */
149
150static inline u32 comp(u32 a, u32 b, u32 mask)
151{
152	return ((a ^ b) & mask) ^ b;
153}
154