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1da177e4 LT |
1 | /* |
2 | * Fast C2P (Chunky-to-Planar) Conversion | |
3 | * | |
4 | * Copyright (C) 2003 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 | #include <linux/string.h> | |
16 | #include "c2p.h" | |
17 | ||
18 | ||
19 | /* | |
20 | * Basic transpose step | |
21 | */ | |
22 | ||
23 | #define _transp(d, i1, i2, shift, mask) \ | |
24 | do { \ | |
25 | u32 t = (d[i1] ^ (d[i2] >> shift)) & mask; \ | |
26 | d[i1] ^= t; \ | |
27 | d[i2] ^= t << shift; \ | |
28 | } while (0) | |
29 | ||
30 | static inline u32 get_mask(int n) | |
31 | { | |
32 | switch (n) { | |
33 | case 1: | |
34 | return 0x55555555; | |
35 | break; | |
36 | ||
37 | case 2: | |
38 | return 0x33333333; | |
39 | break; | |
40 | ||
41 | case 4: | |
42 | return 0x0f0f0f0f; | |
43 | break; | |
44 | ||
45 | case 8: | |
46 | return 0x00ff00ff; | |
47 | break; | |
48 | ||
49 | case 16: | |
50 | return 0x0000ffff; | |
51 | break; | |
52 | } | |
53 | return 0; | |
54 | } | |
55 | ||
56 | #define transp_nx1(d, n) \ | |
57 | do { \ | |
58 | u32 mask = get_mask(n); \ | |
59 | /* First block */ \ | |
60 | _transp(d, 0, 1, n, mask); \ | |
61 | /* Second block */ \ | |
62 | _transp(d, 2, 3, n, mask); \ | |
63 | /* Third block */ \ | |
64 | _transp(d, 4, 5, n, mask); \ | |
65 | /* Fourth block */ \ | |
66 | _transp(d, 6, 7, n, mask); \ | |
67 | } while (0) | |
68 | ||
69 | #define transp_nx2(d, n) \ | |
70 | do { \ | |
71 | u32 mask = get_mask(n); \ | |
72 | /* First block */ \ | |
73 | _transp(d, 0, 2, n, mask); \ | |
74 | _transp(d, 1, 3, n, mask); \ | |
75 | /* Second block */ \ | |
76 | _transp(d, 4, 6, n, mask); \ | |
77 | _transp(d, 5, 7, n, mask); \ | |
78 | } while (0) | |
79 | ||
80 | #define transp_nx4(d, n) \ | |
81 | do { \ | |
82 | u32 mask = get_mask(n); \ | |
83 | _transp(d, 0, 4, n, mask); \ | |
84 | _transp(d, 1, 5, n, mask); \ | |
85 | _transp(d, 2, 6, n, mask); \ | |
86 | _transp(d, 3, 7, n, mask); \ | |
87 | } while (0) | |
88 | ||
89 | #define transp(d, n, m) transp_nx ## m(d, n) | |
90 | ||
91 | ||
92 | /* | |
93 | * Perform a full C2P step on 32 8-bit pixels, stored in 8 32-bit words | |
94 | * containing | |
95 | * - 32 8-bit chunky pixels on input | |
96 | * - permuted planar data on output | |
97 | */ | |
98 | ||
99 | static void c2p_8bpp(u32 d[8]) | |
100 | { | |
101 | transp(d, 16, 4); | |
102 | transp(d, 8, 2); | |
103 | transp(d, 4, 1); | |
104 | transp(d, 2, 4); | |
105 | transp(d, 1, 2); | |
106 | } | |
107 | ||
108 | ||
109 | /* | |
110 | * Array containing the permution indices of the planar data after c2p | |
111 | */ | |
112 | ||
113 | static const int perm_c2p_8bpp[8] = { 7, 5, 3, 1, 6, 4, 2, 0 }; | |
114 | ||
115 | ||
116 | /* | |
117 | * Compose two values, using a bitmask as decision value | |
118 | * This is equivalent to (a & mask) | (b & ~mask) | |
119 | */ | |
120 | ||
121 | static inline unsigned long comp(unsigned long a, unsigned long b, | |
122 | unsigned long mask) | |
123 | { | |
124 | return ((a ^ b) & mask) ^ b; | |
125 | } | |
126 | ||
127 | ||
128 | /* | |
129 | * Store a full block of planar data after c2p conversion | |
130 | */ | |
131 | ||
132 | static inline void store_planar(char *dst, u32 dst_inc, u32 bpp, u32 d[8]) | |
133 | { | |
134 | int i; | |
135 | ||
136 | for (i = 0; i < bpp; i++, dst += dst_inc) | |
137 | *(u32 *)dst = d[perm_c2p_8bpp[i]]; | |
138 | } | |
139 | ||
140 | ||
141 | /* | |
142 | * Store a partial block of planar data after c2p conversion | |
143 | */ | |
144 | ||
145 | static inline void store_planar_masked(char *dst, u32 dst_inc, u32 bpp, | |
146 | u32 d[8], u32 mask) | |
147 | { | |
148 | int i; | |
149 | ||
150 | for (i = 0; i < bpp; i++, dst += dst_inc) | |
151 | *(u32 *)dst = comp(d[perm_c2p_8bpp[i]], *(u32 *)dst, mask); | |
152 | } | |
153 | ||
154 | ||
155 | /* | |
156 | * c2p - Copy 8-bit chunky image data to a planar frame buffer | |
157 | * @dst: Starting address of the planar frame buffer | |
158 | * @dx: Horizontal destination offset (in pixels) | |
159 | * @dy: Vertical destination offset (in pixels) | |
160 | * @width: Image width (in pixels) | |
161 | * @height: Image height (in pixels) | |
162 | * @dst_nextline: Frame buffer offset to the next line (in bytes) | |
163 | * @dst_nextplane: Frame buffer offset to the next plane (in bytes) | |
164 | * @src_nextline: Image offset to the next line (in bytes) | |
165 | * @bpp: Bits per pixel of the planar frame buffer (1-8) | |
166 | */ | |
167 | ||
168 | void c2p(u8 *dst, const u8 *src, u32 dx, u32 dy, u32 width, u32 height, | |
169 | u32 dst_nextline, u32 dst_nextplane, u32 src_nextline, u32 bpp) | |
170 | { | |
171 | int dst_idx; | |
172 | u32 d[8], first, last, w; | |
173 | const u8 *c; | |
174 | u8 *p; | |
175 | ||
176 | dst += dy*dst_nextline+(dx & ~31); | |
177 | dst_idx = dx % 32; | |
178 | first = ~0UL >> dst_idx; | |
179 | last = ~(~0UL >> ((dst_idx+width) % 32)); | |
180 | while (height--) { | |
181 | c = src; | |
182 | p = dst; | |
183 | w = width; | |
184 | if (dst_idx+width <= 32) { | |
185 | /* Single destination word */ | |
186 | first &= last; | |
187 | memset(d, 0, sizeof(d)); | |
188 | memcpy((u8 *)d+dst_idx, c, width); | |
189 | c += width; | |
190 | c2p_8bpp(d); | |
191 | store_planar_masked(p, dst_nextplane, bpp, d, first); | |
192 | p += 4; | |
193 | } else { | |
194 | /* Multiple destination words */ | |
195 | w = width; | |
196 | /* Leading bits */ | |
197 | if (dst_idx) { | |
198 | w = 32 - dst_idx; | |
199 | memset(d, 0, dst_idx); | |
200 | memcpy((u8 *)d+dst_idx, c, w); | |
201 | c += w; | |
202 | c2p_8bpp(d); | |
203 | store_planar_masked(p, dst_nextplane, bpp, d, first); | |
204 | p += 4; | |
205 | w = width-w; | |
206 | } | |
207 | /* Main chunk */ | |
208 | while (w >= 32) { | |
209 | memcpy(d, c, 32); | |
210 | c += 32; | |
211 | c2p_8bpp(d); | |
212 | store_planar(p, dst_nextplane, bpp, d); | |
213 | p += 4; | |
214 | w -= 32; | |
215 | } | |
216 | /* Trailing bits */ | |
217 | w %= 32; | |
218 | if (w > 0) { | |
219 | memcpy(d, c, w); | |
220 | memset((u8 *)d+w, 0, 32-w); | |
221 | c2p_8bpp(d); | |
222 | store_planar_masked(p, dst_nextplane, bpp, d, last); | |
223 | } | |
224 | } | |
225 | src += src_nextline; | |
226 | dst += dst_nextline; | |
227 | } | |
228 | } | |
229 |