| blob | df03f3776dcc3b41503018c0cc7d8045bbe67d88 |
1 /*
2 * Generic function for frame buffer with packed pixels of any depth.
3 *
4 * Copyright (C) 1999-2005 James Simmons <jsimmons@www.infradead.org>
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file COPYING in the main directory of this archive for
8 * more details.
9 *
10 * NOTES:
11 *
12 * This is for cfb packed pixels. Iplan and such are incorporated in the
13 * drivers that need them.
14 *
15 * FIXME
16 *
17 * Also need to add code to deal with cards endians that are different than
18 * the native cpu endians. I also need to deal with MSB position in the word.
19 *
20 * The two functions or copying forward and backward could be split up like
21 * the ones for filling, i.e. in aligned and unaligned versions. This would
22 * help moving some redundant computations and branches out of the loop, too.
23 */
25 #include <linux/module.h>
26 #include <linux/kernel.h>
27 #include <linux/string.h>
28 #include <linux/fb.h>
29 #include <linux/slab.h>
30 #include <asm/types.h>
31 #include <asm/io.h>
34 #if BITS_PER_LONG == 32
35 # define FB_WRITEL fb_writel
36 # define FB_READL fb_readl
37 #else
38 # define FB_WRITEL fb_writeq
39 # define FB_READL fb_readq
40 #endif
42 /*
43 * Generic bitwise copy algorithm
44 */
46 static void
50 {
59 // Same alignment for source and dest
62 // Single word
67 // Multiple destination words
69 // Leading bits
72 dst++;
73 src++;
75 }
77 // Main chunk
89 }
93 // Trailing bits
96 }
98 /* Different alignment for source and dest */
107 // Single destination word
113 // Single source word
116 // Single source word
119 // 2 source words
123 }
127 // Multiple destination words
128 /** We must always remember the last value read, because in case
129 SRC and DST overlap bitwise (e.g. when moving just one pixel in
130 1bpp), we always collect one full long for DST and that might
131 overlap with the current long from SRC. We store this value in
132 'd0'. */
135 // Leading bits
137 // Single source word
140 dst++;
143 // 2 source words
148 dst++;
150 }
155 // Main chunk
172 }
180 }
182 // Trailing bits
185 // Single source word
188 // 2 source words
191 bswapmask);
193 }
196 }
197 }
198 }
199 }
201 /*
202 * Generic bitwise copy algorithm, operating backward
203 */
205 static void
209 {
222 }
228 bswapmask);
231 // Same alignment for source and dest
234 // Single word
239 // Multiple destination words
241 // Leading bits
244 dst--;
245 src--;
247 }
249 // Main chunk
261 }
265 // Trailing bits
268 }
270 // Different alignment for source and dest
279 // Single destination word
284 // Single source word
287 // Single source word
290 // 2 source words
294 }
298 // Multiple destination words
299 /** We must always remember the last value read, because in case
300 SRC and DST overlap bitwise (e.g. when moving just one pixel in
301 1bpp), we always collect one full long for DST and that might
302 overlap with the current long from SRC. We store this value in
303 'd0'. */
307 // Leading bits
309 // Single source word
313 // 2 source words
317 }
321 dst--;
324 // Main chunk
341 }
349 }
351 // Trailing bits
354 // Single source word
357 // 2 source words
360 bswapmask);
362 }
365 }
366 }
367 }
368 }
371 {
383 /* if the beginning of the target area might overlap with the end of
384 the source area, be have to copy the area reverse. */
389 }
391 // split the base of the framebuffer into a long-aligned address and the
392 // index of the first bit
395 // add offset of source and target area
412 }
423 }
424 }
425 }