FFmpeg
pixblockdsp_alpha.c
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1 /*
2  * SIMD-optimized pixel operations
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include "libavutil/attributes.h"
22 #include "libavcodec/pixblockdsp.h"
23 #include "asm.h"
24 
25 static void get_pixels_mvi(int16_t *restrict block,
26  const uint8_t *restrict pixels, ptrdiff_t stride)
27 {
28  int h = 8;
29 
30  do {
31  uint64_t p;
32 
33  p = ldq(pixels);
34  stq(unpkbw(p), block);
35  stq(unpkbw(p >> 32), block + 4);
36 
37  pixels += stride;
38  block += 8;
39  } while (--h);
40 }
41 
42 static void diff_pixels_mvi(int16_t *block, const uint8_t *s1, const uint8_t *s2,
43  ptrdiff_t stride)
44 {
45  int h = 8;
46  uint64_t mask = 0x4040;
47 
48  mask |= mask << 16;
49  mask |= mask << 32;
50  do {
51  uint64_t x, y, c, d, a;
52  uint64_t signs;
53 
54  x = ldq(s1);
55  y = ldq(s2);
56  c = cmpbge(x, y);
57  d = x - y;
58  a = zap(mask, c); /* We use 0x4040404040404040 here... */
59  d += 4 * a; /* ...so we can use s4addq here. */
60  signs = zap(-1, c);
61 
62  stq(unpkbw(d) | (unpkbw(signs) << 8), block);
63  stq(unpkbw(d >> 32) | (unpkbw(signs >> 32) << 8), block + 4);
64 
65  s1 += stride;
66  s2 += stride;
67  block += 8;
68  } while (--h);
69 }
70 
72  unsigned high_bit_depth)
73 {
74  if (amask(AMASK_MVI) == 0) {
75  if (!high_bit_depth)
78  }
79 }
#define ldq(p)
Definition: asm.h:59
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:36
#define cmpbge
Definition: asm.h:92
av_cold void ff_pixblockdsp_init_alpha(PixblockDSPContext *c, AVCodecContext *avctx, unsigned high_bit_depth)
Macro definitions for various function/variable attributes.
The exact code depends on how similar the blocks are and how related they are to the block
uint8_t
#define av_cold
Definition: attributes.h:88
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
void(* diff_pixels)(int16_t *av_restrict block, const uint8_t *s1, const uint8_t *s2, ptrdiff_t stride)
Definition: pixblockdsp.h:35
#define AMASK_MVI
Definition: asm.h:40
#define s2
Definition: regdef.h:39
#define amask
Definition: asm.h:99
static const uint16_t mask[17]
Definition: lzw.c:38
static void get_pixels_mvi(int16_t *restrict block, const uint8_t *restrict pixels, ptrdiff_t stride)
static void diff_pixels_mvi(int16_t *block, const uint8_t *s1, const uint8_t *s2, ptrdiff_t stride)
main external API structure.
Definition: avcodec.h:526
#define zap
Definition: asm.h:97
#define s1
Definition: regdef.h:38
void(* get_pixels)(int16_t *av_restrict block, const uint8_t *pixels, ptrdiff_t stride)
Definition: pixblockdsp.h:29
GLint GLenum GLboolean GLsizei stride
Definition: opengl_enc.c:104
#define unpkbw(a)
Definition: asm.h:146
#define stq(l, p)
Definition: asm.h:69
#define stride