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c2p_iplan2.c
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1 /*
2  * Fast C2P (Chunky-to-Planar) Conversion
3  *
4  * Copyright (C) 2003-2008 Geert Uytterhoeven
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
8  * for more details.
9  */
10 
11 #include <linux/module.h>
12 #include <linux/string.h>
13 
14 #include <asm/unaligned.h>
15 
16 #include "c2p.h"
17 #include "c2p_core.h"
18 
19 
20  /*
21  * Perform a full C2P step on 16 8-bit pixels, stored in 4 32-bit words
22  * containing
23  * - 16 8-bit chunky pixels on input
24  * - permutated planar data (2 planes per 32-bit word) on output
25  */
26 
27 static void c2p_16x8(u32 d[4])
28 {
29  transp4(d, 8, 2);
30  transp4(d, 1, 2);
31  transp4x(d, 16, 2);
32  transp4x(d, 2, 2);
33  transp4(d, 4, 1);
34 }
35 
36 
37  /*
38  * Array containing the permutation indices of the planar data after c2p
39  */
40 
41 static const int perm_c2p_16x8[4] = { 1, 3, 0, 2 };
42 
43 
44  /*
45  * Store a full block of iplan2 data after c2p conversion
46  */
47 
48 static inline void store_iplan2(void *dst, u32 bpp, u32 d[4])
49 {
50  int i;
51 
52  for (i = 0; i < bpp/2; i++, dst += 4)
53  put_unaligned_be32(d[perm_c2p_16x8[i]], dst);
54 }
55 
56 
57  /*
58  * Store a partial block of iplan2 data after c2p conversion
59  */
60 
61 static inline void store_iplan2_masked(void *dst, u32 bpp, u32 d[4], u32 mask)
62 {
63  int i;
64 
65  for (i = 0; i < bpp/2; i++, dst += 4)
66  put_unaligned_be32(comp(d[perm_c2p_16x8[i]],
67  get_unaligned_be32(dst), mask),
68  dst);
69 }
70 
71 
72  /*
73  * c2p_iplan2 - Copy 8-bit chunky image data to an interleaved planar
74  * frame buffer with 2 bytes of interleave
75  * @dst: Starting address of the planar frame buffer
76  * @dx: Horizontal destination offset (in pixels)
77  * @dy: Vertical destination offset (in pixels)
78  * @width: Image width (in pixels)
79  * @height: Image height (in pixels)
80  * @dst_nextline: Frame buffer offset to the next line (in bytes)
81  * @src_nextline: Image offset to the next line (in bytes)
82  * @bpp: Bits per pixel of the planar frame buffer (2, 4, or 8)
83  */
84 
85 void c2p_iplan2(void *dst, const void *src, u32 dx, u32 dy, u32 width,
86  u32 height, u32 dst_nextline, u32 src_nextline, u32 bpp)
87 {
88  union {
89  u8 pixels[16];
90  u32 words[4];
91  } d;
92  u32 dst_idx, first, last, w;
93  const u8 *c;
94  void *p;
95 
96  dst += dy*dst_nextline+(dx & ~15)*bpp;
97  dst_idx = dx % 16;
98  first = 0xffffU >> dst_idx;
99  first |= first << 16;
100  last = 0xffffU ^ (0xffffU >> ((dst_idx+width) % 16));
101  last |= last << 16;
102  while (height--) {
103  c = src;
104  p = dst;
105  w = width;
106  if (dst_idx+width <= 16) {
107  /* Single destination word */
108  first &= last;
109  memset(d.pixels, 0, sizeof(d));
110  memcpy(d.pixels+dst_idx, c, width);
111  c += width;
112  c2p_16x8(d.words);
113  store_iplan2_masked(p, bpp, d.words, first);
114  p += bpp*2;
115  } else {
116  /* Multiple destination words */
117  w = width;
118  /* Leading bits */
119  if (dst_idx) {
120  w = 16 - dst_idx;
121  memset(d.pixels, 0, dst_idx);
122  memcpy(d.pixels+dst_idx, c, w);
123  c += w;
124  c2p_16x8(d.words);
125  store_iplan2_masked(p, bpp, d.words, first);
126  p += bpp*2;
127  w = width-w;
128  }
129  /* Main chunk */
130  while (w >= 16) {
131  memcpy(d.pixels, c, 16);
132  c += 16;
133  c2p_16x8(d.words);
134  store_iplan2(p, bpp, d.words);
135  p += bpp*2;
136  w -= 16;
137  }
138  /* Trailing bits */
139  w %= 16;
140  if (w > 0) {
141  memcpy(d.pixels, c, w);
142  memset(d.pixels+w, 0, 16-w);
143  c2p_16x8(d.words);
144  store_iplan2_masked(p, bpp, d.words, last);
145  }
146  }
147  src += src_nextline;
148  dst += dst_nextline;
149  }
150 }
152 
153 MODULE_LICENSE("GPL");