idct8x8: Fix undefined negative shifts
[libav.git] / libavcodec / simple_idct_template.c
1 /*
2 * Simple IDCT
3 *
4 * Copyright (c) 2001 Michael Niedermayer <michaelni@gmx.at>
5 *
6 * This file is part of Libav.
7 *
8 * Libav is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * Libav is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with Libav; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 /**
24 * @file
25 * simpleidct in C.
26 */
27
28 /*
29 based upon some outcommented c code from mpeg2dec (idct_mmx.c
30 written by Aaron Holtzman <aholtzma@ess.engr.uvic.ca>)
31 */
32
33 #include "simple_idct.h"
34
35 #include "bit_depth_template.c"
36
37 #undef W1
38 #undef W2
39 #undef W3
40 #undef W4
41 #undef W5
42 #undef W6
43 #undef W7
44 #undef ROW_SHIFT
45 #undef COL_SHIFT
46 #undef DC_SHIFT
47 #undef MUL
48 #undef MAC
49
50 #if BIT_DEPTH == 8
51
52 #define W1 22725 //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
53 #define W2 21407 //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
54 #define W3 19266 //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
55 #define W4 16383 //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
56 #define W5 12873 //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
57 #define W6 8867 //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
58 #define W7 4520 //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
59
60 #define ROW_SHIFT 11
61 #define COL_SHIFT 20
62 #define DC_SHIFT 3
63
64 #define MUL(a, b) MUL16(a, b)
65 #define MAC(a, b, c) MAC16(a, b, c)
66
67 #elif BIT_DEPTH == 10
68
69 #define W1 90901
70 #define W2 85627
71 #define W3 77062
72 #define W4 65535
73 #define W5 51491
74 #define W6 35468
75 #define W7 18081
76
77 #define ROW_SHIFT 15
78 #define COL_SHIFT 20
79 #define DC_SHIFT 1
80
81 #define MUL(a, b) ((a) * (b))
82 #define MAC(a, b, c) ((a) += (b) * (c))
83
84 #else
85
86 #error "Unsupported bitdepth"
87
88 #endif
89
90 static inline void FUNC(idctRowCondDC)(int16_t *row, int extra_shift)
91 {
92 int a0, a1, a2, a3, b0, b1, b2, b3;
93
94 #if HAVE_FAST_64BIT
95 #define ROW0_MASK (0xffffLL << 48 * HAVE_BIGENDIAN)
96 if (((((uint64_t *)row)[0] & ~ROW0_MASK) | ((uint64_t *)row)[1]) == 0) {
97 uint64_t temp;
98 if (DC_SHIFT - extra_shift > 0) {
99 temp = (row[0] * (1 << (DC_SHIFT - extra_shift))) & 0xffff;
100 } else {
101 temp = (row[0] >> (extra_shift - DC_SHIFT)) & 0xffff;
102 }
103 temp += temp * (1 << 16);
104 temp += temp * ((uint64_t) 1 << 32);
105 ((uint64_t *)row)[0] = temp;
106 ((uint64_t *)row)[1] = temp;
107 return;
108 }
109 #else
110 if (!(((uint32_t*)row)[1] |
111 ((uint32_t*)row)[2] |
112 ((uint32_t*)row)[3] |
113 row[1])) {
114 uint32_t temp;
115 if (DC_SHIFT - extra_shift > 0) {
116 temp = (row[0] * (1 << (DC_SHIFT - extra_shift))) & 0xffff;
117 } else {
118 temp = (row[0] >> (extra_shift - DC_SHIFT)) & 0xffff;
119 }
120 temp += temp * (1 << 16);
121 ((uint32_t*)row)[0]=((uint32_t*)row)[1] =
122 ((uint32_t*)row)[2]=((uint32_t*)row)[3] = temp;
123 return;
124 }
125 #endif
126
127 a0 = (W4 * row[0]) + (1 << (ROW_SHIFT - 1));
128 a1 = a0;
129 a2 = a0;
130 a3 = a0;
131
132 a0 += W2 * row[2];
133 a1 += W6 * row[2];
134 a2 -= W6 * row[2];
135 a3 -= W2 * row[2];
136
137 b0 = MUL(W1, row[1]);
138 MAC(b0, W3, row[3]);
139 b1 = MUL(W3, row[1]);
140 MAC(b1, -W7, row[3]);
141 b2 = MUL(W5, row[1]);
142 MAC(b2, -W1, row[3]);
143 b3 = MUL(W7, row[1]);
144 MAC(b3, -W5, row[3]);
145
146 if (AV_RN64A(row + 4)) {
147 a0 += W4*row[4] + W6*row[6];
148 a1 += - W4*row[4] - W2*row[6];
149 a2 += - W4*row[4] + W2*row[6];
150 a3 += W4*row[4] - W6*row[6];
151
152 MAC(b0, W5, row[5]);
153 MAC(b0, W7, row[7]);
154
155 MAC(b1, -W1, row[5]);
156 MAC(b1, -W5, row[7]);
157
158 MAC(b2, W7, row[5]);
159 MAC(b2, W3, row[7]);
160
161 MAC(b3, W3, row[5]);
162 MAC(b3, -W1, row[7]);
163 }
164
165 row[0] = (a0 + b0) >> (ROW_SHIFT + extra_shift);
166 row[7] = (a0 - b0) >> (ROW_SHIFT + extra_shift);
167 row[1] = (a1 + b1) >> (ROW_SHIFT + extra_shift);
168 row[6] = (a1 - b1) >> (ROW_SHIFT + extra_shift);
169 row[2] = (a2 + b2) >> (ROW_SHIFT + extra_shift);
170 row[5] = (a2 - b2) >> (ROW_SHIFT + extra_shift);
171 row[3] = (a3 + b3) >> (ROW_SHIFT + extra_shift);
172 row[4] = (a3 - b3) >> (ROW_SHIFT + extra_shift);
173 }
174
175 #define IDCT_COLS do { \
176 a0 = W4 * (col[8*0] + ((1<<(COL_SHIFT-1))/W4)); \
177 a1 = a0; \
178 a2 = a0; \
179 a3 = a0; \
180 \
181 a0 += W2*col[8*2]; \
182 a1 += W6*col[8*2]; \
183 a2 += -W6*col[8*2]; \
184 a3 += -W2*col[8*2]; \
185 \
186 b0 = MUL(W1, col[8*1]); \
187 b1 = MUL(W3, col[8*1]); \
188 b2 = MUL(W5, col[8*1]); \
189 b3 = MUL(W7, col[8*1]); \
190 \
191 MAC(b0, W3, col[8*3]); \
192 MAC(b1, -W7, col[8*3]); \
193 MAC(b2, -W1, col[8*3]); \
194 MAC(b3, -W5, col[8*3]); \
195 \
196 if (col[8*4]) { \
197 a0 += W4*col[8*4]; \
198 a1 += -W4*col[8*4]; \
199 a2 += -W4*col[8*4]; \
200 a3 += W4*col[8*4]; \
201 } \
202 \
203 if (col[8*5]) { \
204 MAC(b0, W5, col[8*5]); \
205 MAC(b1, -W1, col[8*5]); \
206 MAC(b2, W7, col[8*5]); \
207 MAC(b3, W3, col[8*5]); \
208 } \
209 \
210 if (col[8*6]) { \
211 a0 += W6*col[8*6]; \
212 a1 += -W2*col[8*6]; \
213 a2 += W2*col[8*6]; \
214 a3 += -W6*col[8*6]; \
215 } \
216 \
217 if (col[8*7]) { \
218 MAC(b0, W7, col[8*7]); \
219 MAC(b1, -W5, col[8*7]); \
220 MAC(b2, W3, col[8*7]); \
221 MAC(b3, -W1, col[8*7]); \
222 } \
223 } while (0)
224
225 static inline void FUNC(idctSparseColPut)(pixel *dest, int line_size,
226 int16_t *col)
227 {
228 int a0, a1, a2, a3, b0, b1, b2, b3;
229
230 IDCT_COLS;
231
232 dest[0] = av_clip_pixel((a0 + b0) >> COL_SHIFT);
233 dest += line_size;
234 dest[0] = av_clip_pixel((a1 + b1) >> COL_SHIFT);
235 dest += line_size;
236 dest[0] = av_clip_pixel((a2 + b2) >> COL_SHIFT);
237 dest += line_size;
238 dest[0] = av_clip_pixel((a3 + b3) >> COL_SHIFT);
239 dest += line_size;
240 dest[0] = av_clip_pixel((a3 - b3) >> COL_SHIFT);
241 dest += line_size;
242 dest[0] = av_clip_pixel((a2 - b2) >> COL_SHIFT);
243 dest += line_size;
244 dest[0] = av_clip_pixel((a1 - b1) >> COL_SHIFT);
245 dest += line_size;
246 dest[0] = av_clip_pixel((a0 - b0) >> COL_SHIFT);
247 }
248
249 static inline void FUNC(idctSparseColAdd)(pixel *dest, int line_size,
250 int16_t *col)
251 {
252 int a0, a1, a2, a3, b0, b1, b2, b3;
253
254 IDCT_COLS;
255
256 dest[0] = av_clip_pixel(dest[0] + ((a0 + b0) >> COL_SHIFT));
257 dest += line_size;
258 dest[0] = av_clip_pixel(dest[0] + ((a1 + b1) >> COL_SHIFT));
259 dest += line_size;
260 dest[0] = av_clip_pixel(dest[0] + ((a2 + b2) >> COL_SHIFT));
261 dest += line_size;
262 dest[0] = av_clip_pixel(dest[0] + ((a3 + b3) >> COL_SHIFT));
263 dest += line_size;
264 dest[0] = av_clip_pixel(dest[0] + ((a3 - b3) >> COL_SHIFT));
265 dest += line_size;
266 dest[0] = av_clip_pixel(dest[0] + ((a2 - b2) >> COL_SHIFT));
267 dest += line_size;
268 dest[0] = av_clip_pixel(dest[0] + ((a1 - b1) >> COL_SHIFT));
269 dest += line_size;
270 dest[0] = av_clip_pixel(dest[0] + ((a0 - b0) >> COL_SHIFT));
271 }
272
273 static inline void FUNC(idctSparseCol)(int16_t *col)
274 {
275 int a0, a1, a2, a3, b0, b1, b2, b3;
276
277 IDCT_COLS;
278
279 col[0 ] = ((a0 + b0) >> COL_SHIFT);
280 col[8 ] = ((a1 + b1) >> COL_SHIFT);
281 col[16] = ((a2 + b2) >> COL_SHIFT);
282 col[24] = ((a3 + b3) >> COL_SHIFT);
283 col[32] = ((a3 - b3) >> COL_SHIFT);
284 col[40] = ((a2 - b2) >> COL_SHIFT);
285 col[48] = ((a1 - b1) >> COL_SHIFT);
286 col[56] = ((a0 - b0) >> COL_SHIFT);
287 }
288
289 void FUNC(ff_simple_idct_put)(uint8_t *dest_, int line_size, int16_t *block)
290 {
291 pixel *dest = (pixel *)dest_;
292 int i;
293
294 line_size /= sizeof(pixel);
295
296 for (i = 0; i < 8; i++)
297 FUNC(idctRowCondDC)(block + i*8, 0);
298
299 for (i = 0; i < 8; i++)
300 FUNC(idctSparseColPut)(dest + i, line_size, block + i);
301 }
302
303 void FUNC(ff_simple_idct_add)(uint8_t *dest_, int line_size, int16_t *block)
304 {
305 pixel *dest = (pixel *)dest_;
306 int i;
307
308 line_size /= sizeof(pixel);
309
310 for (i = 0; i < 8; i++)
311 FUNC(idctRowCondDC)(block + i*8, 0);
312
313 for (i = 0; i < 8; i++)
314 FUNC(idctSparseColAdd)(dest + i, line_size, block + i);
315 }
316
317 void FUNC(ff_simple_idct)(int16_t *block)
318 {
319 int i;
320
321 for (i = 0; i < 8; i++)
322 FUNC(idctRowCondDC)(block + i*8, 0);
323
324 for (i = 0; i < 8; i++)
325 FUNC(idctSparseCol)(block + i);
326 }