1 /*
2 * Fast C2P (Chunky-to-Planar) Conversion
3 *
4 * NOTES:
5 * - This code was inspired by Scout's C2P tutorial
6 * - It assumes to run on a big endian system
7 *
8 * Copyright © 2003-2008 Geert Uytterhoeven
9 *
10 * Permission is hereby granted, free of charge, to any person obtaining a
11 * copy of this software and associated documentation files (the "Software"),
12 * to deal in the Software without restriction, including without limitation
13 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
14 * and/or sell copies of the Software, and to permit persons to whom the
15 * Software is furnished to do so, subject to the following conditions:
16 *
17 * The above copyright notice and this permission notice (including the next
18 * paragraph) shall be included in all copies or substantial portions of the
19 * Software.
20 *
21 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
22 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
23 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
24 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
25 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
26 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
27 * DEALINGS IN THE SOFTWARE.
28 */
29
30
31 /*
32 * Basic transpose step
33 */
34
_transp(CARD32 d[],unsigned int i1,unsigned int i2,unsigned int shift,CARD32 mask)35 static inline void _transp(CARD32 d[], unsigned int i1, unsigned int i2,
36 unsigned int shift, CARD32 mask)
37 {
38 CARD32 t = (d[i1] ^ (d[i2] >> shift)) & mask;
39
40 d[i1] ^= t;
41 d[i2] ^= t << shift;
42 }
43
44
c2p_unsupported(void)45 static inline void c2p_unsupported(void) {
46 BUG_WARN(1);
47 }
48
get_mask(unsigned int n)49 static inline CARD32 get_mask(unsigned int n)
50 {
51 switch (n) {
52 case 1:
53 return 0x55555555;
54
55 case 2:
56 return 0x33333333;
57
58 case 4:
59 return 0x0f0f0f0f;
60
61 case 8:
62 return 0x00ff00ff;
63
64 case 16:
65 return 0x0000ffff;
66 }
67
68 c2p_unsupported();
69 return 0;
70 }
71
72
73 /*
74 * Transpose operations on 8 32-bit words
75 */
76
transp8(CARD32 d[],unsigned int n,unsigned int m)77 static inline void transp8(CARD32 d[], unsigned int n, unsigned int m)
78 {
79 CARD32 mask = get_mask(n);
80
81 switch (m) {
82 case 1:
83 /* First n x 1 block */
84 _transp(d, 0, 1, n, mask);
85 /* Second n x 1 block */
86 _transp(d, 2, 3, n, mask);
87 /* Third n x 1 block */
88 _transp(d, 4, 5, n, mask);
89 /* Fourth n x 1 block */
90 _transp(d, 6, 7, n, mask);
91 return;
92
93 case 2:
94 /* First n x 2 block */
95 _transp(d, 0, 2, n, mask);
96 _transp(d, 1, 3, n, mask);
97 /* Second n x 2 block */
98 _transp(d, 4, 6, n, mask);
99 _transp(d, 5, 7, n, mask);
100 return;
101
102 case 4:
103 /* Single n x 4 block */
104 _transp(d, 0, 4, n, mask);
105 _transp(d, 1, 5, n, mask);
106 _transp(d, 2, 6, n, mask);
107 _transp(d, 3, 7, n, mask);
108 return;
109 }
110
111 c2p_unsupported();
112 }
113
114
115 /*
116 * Transpose operations on 4 32-bit words
117 */
118
transp4(CARD32 d[],unsigned int n,unsigned int m)119 static inline void transp4(CARD32 d[], unsigned int n, unsigned int m)
120 {
121 CARD32 mask = get_mask(n);
122
123 switch (m) {
124 case 1:
125 /* First n x 1 block */
126 _transp(d, 0, 1, n, mask);
127 /* Second n x 1 block */
128 _transp(d, 2, 3, n, mask);
129 return;
130
131 case 2:
132 /* Single n x 2 block */
133 _transp(d, 0, 2, n, mask);
134 _transp(d, 1, 3, n, mask);
135 return;
136 }
137
138 c2p_unsupported();
139 }
140
141
142 /*
143 * Transpose operations on 4 32-bit words (reverse order)
144 */
145
transp4x(CARD32 d[],unsigned int n,unsigned int m)146 static inline void transp4x(CARD32 d[], unsigned int n, unsigned int m)
147 {
148 CARD32 mask = get_mask(n);
149
150 switch (m) {
151 case 2:
152 /* Single n x 2 block */
153 _transp(d, 2, 0, n, mask);
154 _transp(d, 3, 1, n, mask);
155 return;
156 }
157
158 c2p_unsupported();
159 }
160
161
162 /*
163 * Transpose operations on 2 32-bit words
164 */
165
transp2(CARD32 d[],unsigned int n)166 static inline void transp2(CARD32 d[], unsigned int n)
167 {
168 CARD32 mask = get_mask(n);
169
170 /* Single n x 1 block */
171 _transp(d, 0, 1, n, mask);
172 return;
173 }
174
175
176 /*
177 * Transpose operations on 2 32-bit words (reverse order)
178 */
179
transp2x(CARD32 d[],unsigned int n)180 static inline void transp2x(CARD32 d[], unsigned int n)
181 {
182 CARD32 mask = get_mask(n);
183
184 /* Single n x 1 block */
185 _transp(d, 1, 0, n, mask);
186 return;
187 }
188