1 /*
2  * Copyright (c) 2016, Alliance for Open Media. All rights reserved
3  *
4  * This source code is subject to the terms of the BSD 2 Clause License and
5  * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
6  * was not distributed with this source code in the LICENSE file, you can
7  * obtain it at www.aomedia.org/license/software. If the Alliance for Open
8  * Media Patent License 1.0 was not distributed with this source code in the
9  * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
10  */
11 
12 #include "./aom_config.h"
13 #include "aom_dsp/aom_dsp_common.h"
14 #include "aom_mem/aom_mem.h"
15 #include "av1/common/entropymode.h"
16 #include "av1/common/thread_common.h"
17 #include "av1/common/reconinter.h"
18 
19 #if CONFIG_MULTITHREAD
mutex_lock(pthread_mutex_t * const mutex)20 static INLINE void mutex_lock(pthread_mutex_t *const mutex) {
21   const int kMaxTryLocks = 4000;
22   int locked = 0;
23   int i;
24 
25   for (i = 0; i < kMaxTryLocks; ++i) {
26     if (!pthread_mutex_trylock(mutex)) {
27       locked = 1;
28       break;
29     }
30   }
31 
32   if (!locked) pthread_mutex_lock(mutex);
33 }
34 #endif  // CONFIG_MULTITHREAD
35 
sync_read(AV1LfSync * const lf_sync,int r,int c)36 static INLINE void sync_read(AV1LfSync *const lf_sync, int r, int c) {
37 #if CONFIG_MULTITHREAD
38   const int nsync = lf_sync->sync_range;
39 
40   if (r && !(c & (nsync - 1))) {
41     pthread_mutex_t *const mutex = &lf_sync->mutex_[r - 1];
42     mutex_lock(mutex);
43 
44     while (c > lf_sync->cur_sb_col[r - 1] - nsync) {
45       pthread_cond_wait(&lf_sync->cond_[r - 1], mutex);
46     }
47     pthread_mutex_unlock(mutex);
48   }
49 #else
50   (void)lf_sync;
51   (void)r;
52   (void)c;
53 #endif  // CONFIG_MULTITHREAD
54 }
55 
sync_write(AV1LfSync * const lf_sync,int r,int c,const int sb_cols)56 static INLINE void sync_write(AV1LfSync *const lf_sync, int r, int c,
57                               const int sb_cols) {
58 #if CONFIG_MULTITHREAD
59   const int nsync = lf_sync->sync_range;
60   int cur;
61   // Only signal when there are enough filtered SB for next row to run.
62   int sig = 1;
63 
64   if (c < sb_cols - 1) {
65     cur = c;
66     if (c % nsync) sig = 0;
67   } else {
68     cur = sb_cols + nsync;
69   }
70 
71   if (sig) {
72     mutex_lock(&lf_sync->mutex_[r]);
73 
74     lf_sync->cur_sb_col[r] = cur;
75 
76     pthread_cond_signal(&lf_sync->cond_[r]);
77     pthread_mutex_unlock(&lf_sync->mutex_[r]);
78   }
79 #else
80   (void)lf_sync;
81   (void)r;
82   (void)c;
83   (void)sb_cols;
84 #endif  // CONFIG_MULTITHREAD
85 }
86 
87 #if !CONFIG_EXT_PARTITION_TYPES
get_loop_filter_path(int y_only,struct macroblockd_plane * planes)88 static INLINE enum lf_path get_loop_filter_path(
89     int y_only, struct macroblockd_plane *planes) {
90   if (y_only)
91     return LF_PATH_444;
92   else if (planes[1].subsampling_y == 1 && planes[1].subsampling_x == 1)
93     return LF_PATH_420;
94   else if (planes[1].subsampling_y == 0 && planes[1].subsampling_x == 0)
95     return LF_PATH_444;
96   else
97     return LF_PATH_SLOW;
98 }
99 
loop_filter_block_plane_ver(AV1_COMMON * cm,struct macroblockd_plane * planes,int plane,MODE_INFO ** mi,int mi_row,int mi_col,enum lf_path path,LOOP_FILTER_MASK * lfm)100 static INLINE void loop_filter_block_plane_ver(
101     AV1_COMMON *cm, struct macroblockd_plane *planes, int plane,
102     MODE_INFO **mi, int mi_row, int mi_col, enum lf_path path,
103     LOOP_FILTER_MASK *lfm) {
104   if (plane == 0) {
105     av1_filter_block_plane_ss00_ver(cm, &planes[0], mi_row, lfm);
106   } else {
107     switch (path) {
108       case LF_PATH_420:
109         av1_filter_block_plane_ss11_ver(cm, &planes[plane], mi_row, lfm);
110         break;
111       case LF_PATH_444:
112         av1_filter_block_plane_ss00_ver(cm, &planes[plane], mi_row, lfm);
113         break;
114       case LF_PATH_SLOW:
115         av1_filter_block_plane_non420_ver(cm, &planes[plane], mi, mi_row,
116                                           mi_col, plane);
117         break;
118     }
119   }
120 }
121 
loop_filter_block_plane_hor(AV1_COMMON * cm,struct macroblockd_plane * planes,int plane,MODE_INFO ** mi,int mi_row,int mi_col,enum lf_path path,LOOP_FILTER_MASK * lfm)122 static INLINE void loop_filter_block_plane_hor(
123     AV1_COMMON *cm, struct macroblockd_plane *planes, int plane,
124     MODE_INFO **mi, int mi_row, int mi_col, enum lf_path path,
125     LOOP_FILTER_MASK *lfm) {
126   if (plane == 0) {
127     av1_filter_block_plane_ss00_hor(cm, &planes[0], mi_row, lfm);
128   } else {
129     switch (path) {
130       case LF_PATH_420:
131         av1_filter_block_plane_ss11_hor(cm, &planes[plane], mi_row, lfm);
132         break;
133       case LF_PATH_444:
134         av1_filter_block_plane_ss00_hor(cm, &planes[plane], mi_row, lfm);
135         break;
136       case LF_PATH_SLOW:
137         av1_filter_block_plane_non420_hor(cm, &planes[plane], mi, mi_row,
138                                           mi_col, plane);
139         break;
140     }
141   }
142 }
143 #endif
144 // Row-based multi-threaded loopfilter hook
145 #if CONFIG_PARALLEL_DEBLOCKING
loop_filter_ver_row_worker(AV1LfSync * const lf_sync,LFWorkerData * const lf_data)146 static int loop_filter_ver_row_worker(AV1LfSync *const lf_sync,
147                                       LFWorkerData *const lf_data) {
148   const int num_planes = lf_data->y_only ? 1 : MAX_MB_PLANE;
149   int mi_row, mi_col;
150 #if !CONFIG_EXT_PARTITION_TYPES
151   enum lf_path path = get_loop_filter_path(lf_data->y_only, lf_data->planes);
152 #endif
153   for (mi_row = lf_data->start; mi_row < lf_data->stop;
154        mi_row += lf_sync->num_workers * lf_data->cm->mib_size) {
155     MODE_INFO **const mi =
156         lf_data->cm->mi_grid_visible + mi_row * lf_data->cm->mi_stride;
157 
158     for (mi_col = 0; mi_col < lf_data->cm->mi_cols;
159          mi_col += lf_data->cm->mib_size) {
160       LOOP_FILTER_MASK lfm;
161       int plane;
162 
163       av1_setup_dst_planes(lf_data->planes, lf_data->cm->sb_size,
164                            lf_data->frame_buffer, mi_row, mi_col);
165       av1_setup_mask(lf_data->cm, mi_row, mi_col, mi + mi_col,
166                      lf_data->cm->mi_stride, &lfm);
167 
168 #if CONFIG_EXT_PARTITION_TYPES
169       for (plane = 0; plane < num_planes; ++plane)
170         av1_filter_block_plane_non420_ver(lf_data->cm, &lf_data->planes[plane],
171                                           mi + mi_col, mi_row, mi_col, plane);
172 #else
173 
174       for (plane = 0; plane < num_planes; ++plane)
175         loop_filter_block_plane_ver(lf_data->cm, lf_data->planes, plane,
176                                     mi + mi_col, mi_row, mi_col, path, &lfm);
177 #endif
178     }
179   }
180   return 1;
181 }
182 
loop_filter_hor_row_worker(AV1LfSync * const lf_sync,LFWorkerData * const lf_data)183 static int loop_filter_hor_row_worker(AV1LfSync *const lf_sync,
184                                       LFWorkerData *const lf_data) {
185   const int num_planes = lf_data->y_only ? 1 : MAX_MB_PLANE;
186   const int sb_cols =
187       mi_cols_aligned_to_sb(lf_data->cm) >> lf_data->cm->mib_size_log2;
188   int mi_row, mi_col;
189 #if !CONFIG_EXT_PARTITION_TYPES
190   enum lf_path path = get_loop_filter_path(lf_data->y_only, lf_data->planes);
191 #endif
192 
193   for (mi_row = lf_data->start; mi_row < lf_data->stop;
194        mi_row += lf_sync->num_workers * lf_data->cm->mib_size) {
195     MODE_INFO **const mi =
196         lf_data->cm->mi_grid_visible + mi_row * lf_data->cm->mi_stride;
197 
198     for (mi_col = 0; mi_col < lf_data->cm->mi_cols;
199          mi_col += lf_data->cm->mib_size) {
200       const int r = mi_row >> lf_data->cm->mib_size_log2;
201       const int c = mi_col >> lf_data->cm->mib_size_log2;
202       LOOP_FILTER_MASK lfm;
203       int plane;
204 
205       // TODO(wenhao.zhang@intel.com): For better parallelization, reorder
206       // the outer loop to column-based and remove the synchronizations here.
207       sync_read(lf_sync, r, c);
208 
209       av1_setup_dst_planes(lf_data->planes, lf_data->cm->sb_size,
210                            lf_data->frame_buffer, mi_row, mi_col);
211       av1_setup_mask(lf_data->cm, mi_row, mi_col, mi + mi_col,
212                      lf_data->cm->mi_stride, &lfm);
213 #if CONFIG_EXT_PARTITION_TYPES
214       for (plane = 0; plane < num_planes; ++plane)
215         av1_filter_block_plane_non420_hor(lf_data->cm, &lf_data->planes[plane],
216                                           mi + mi_col, mi_row, mi_col, plane);
217 #else
218       for (plane = 0; plane < num_planes; ++plane)
219         loop_filter_block_plane_hor(lf_data->cm, lf_data->planes, plane,
220                                     mi + mi_col, mi_row, mi_col, path, &lfm);
221 #endif
222       sync_write(lf_sync, r, c, sb_cols);
223     }
224   }
225   return 1;
226 }
227 #else  //  CONFIG_PARALLEL_DEBLOCKING
loop_filter_row_worker(AV1LfSync * const lf_sync,LFWorkerData * const lf_data)228 static int loop_filter_row_worker(AV1LfSync *const lf_sync,
229                                   LFWorkerData *const lf_data) {
230   const int num_planes = lf_data->y_only ? 1 : MAX_MB_PLANE;
231   const int sb_cols =
232       mi_cols_aligned_to_sb(lf_data->cm) >> lf_data->cm->mib_size_log2;
233   int mi_row, mi_col;
234 #if !CONFIG_EXT_PARTITION_TYPES
235   enum lf_path path = get_loop_filter_path(lf_data->y_only, lf_data->planes);
236 #endif  // !CONFIG_EXT_PARTITION_TYPES
237 
238 #if CONFIG_EXT_PARTITION
239   printf(
240       "STOPPING: This code has not been modified to work with the "
241       "extended coding unit size experiment");
242   exit(EXIT_FAILURE);
243 #endif  // CONFIG_EXT_PARTITION
244 
245   for (mi_row = lf_data->start; mi_row < lf_data->stop;
246        mi_row += lf_sync->num_workers * lf_data->cm->mib_size) {
247     MODE_INFO **const mi =
248         lf_data->cm->mi_grid_visible + mi_row * lf_data->cm->mi_stride;
249 
250     for (mi_col = 0; mi_col < lf_data->cm->mi_cols;
251          mi_col += lf_data->cm->mib_size) {
252       const int r = mi_row >> lf_data->cm->mib_size_log2;
253       const int c = mi_col >> lf_data->cm->mib_size_log2;
254 #if !CONFIG_EXT_PARTITION_TYPES
255       LOOP_FILTER_MASK lfm;
256 #endif
257       int plane;
258 
259       sync_read(lf_sync, r, c);
260 
261       av1_setup_dst_planes(lf_data->planes, lf_data->cm->sb_size,
262                            lf_data->frame_buffer, mi_row, mi_col);
263 #if CONFIG_EXT_PARTITION_TYPES
264       for (plane = 0; plane < num_planes; ++plane) {
265         av1_filter_block_plane_non420_ver(lf_data->cm, &lf_data->planes[plane],
266                                           mi + mi_col, mi_row, mi_col, plane);
267         av1_filter_block_plane_non420_hor(lf_data->cm, &lf_data->planes[plane],
268                                           mi + mi_col, mi_row, mi_col, plane);
269       }
270 #else
271       av1_setup_mask(lf_data->cm, mi_row, mi_col, mi + mi_col,
272                      lf_data->cm->mi_stride, &lfm);
273 
274       for (plane = 0; plane < num_planes; ++plane) {
275         loop_filter_block_plane_ver(lf_data->cm, lf_data->planes, plane,
276                                     mi + mi_col, mi_row, mi_col, path, &lfm);
277         loop_filter_block_plane_hor(lf_data->cm, lf_data->planes, plane,
278                                     mi + mi_col, mi_row, mi_col, path, &lfm);
279       }
280 #endif  // CONFIG_EXT_PARTITION_TYPES
281       sync_write(lf_sync, r, c, sb_cols);
282     }
283   }
284   return 1;
285 }
286 #endif  //  CONFIG_PARALLEL_DEBLOCKING
287 
loop_filter_rows_mt(YV12_BUFFER_CONFIG * frame,AV1_COMMON * cm,struct macroblockd_plane * planes,int start,int stop,int y_only,AVxWorker * workers,int nworkers,AV1LfSync * lf_sync)288 static void loop_filter_rows_mt(YV12_BUFFER_CONFIG *frame, AV1_COMMON *cm,
289                                 struct macroblockd_plane *planes, int start,
290                                 int stop, int y_only, AVxWorker *workers,
291                                 int nworkers, AV1LfSync *lf_sync) {
292 #if CONFIG_EXT_PARTITION
293   printf(
294       "STOPPING: This code has not been modified to work with the "
295       "extended coding unit size experiment");
296   exit(EXIT_FAILURE);
297 #endif  // CONFIG_EXT_PARTITION
298 
299   const AVxWorkerInterface *const winterface = aom_get_worker_interface();
300   // Number of superblock rows and cols
301   const int sb_rows = mi_rows_aligned_to_sb(cm) >> cm->mib_size_log2;
302   // Decoder may allocate more threads than number of tiles based on user's
303   // input.
304   const int tile_cols = cm->tile_cols;
305   const int num_workers = AOMMIN(nworkers, tile_cols);
306   int i;
307 
308   if (!lf_sync->sync_range || sb_rows != lf_sync->rows ||
309       num_workers > lf_sync->num_workers) {
310     av1_loop_filter_dealloc(lf_sync);
311     av1_loop_filter_alloc(lf_sync, cm, sb_rows, cm->width, num_workers);
312   }
313 
314 // Set up loopfilter thread data.
315 // The decoder is capping num_workers because it has been observed that using
316 // more threads on the loopfilter than there are cores will hurt performance
317 // on Android. This is because the system will only schedule the tile decode
318 // workers on cores equal to the number of tile columns. Then if the decoder
319 // tries to use more threads for the loopfilter, it will hurt performance
320 // because of contention. If the multithreading code changes in the future
321 // then the number of workers used by the loopfilter should be revisited.
322 
323 #if CONFIG_PARALLEL_DEBLOCKING
324   // Initialize cur_sb_col to -1 for all SB rows.
325   memset(lf_sync->cur_sb_col, -1, sizeof(*lf_sync->cur_sb_col) * sb_rows);
326 
327   // Filter all the vertical edges in the whole frame
328   for (i = 0; i < num_workers; ++i) {
329     AVxWorker *const worker = &workers[i];
330     LFWorkerData *const lf_data = &lf_sync->lfdata[i];
331 
332     worker->hook = (AVxWorkerHook)loop_filter_ver_row_worker;
333     worker->data1 = lf_sync;
334     worker->data2 = lf_data;
335 
336     // Loopfilter data
337     av1_loop_filter_data_reset(lf_data, frame, cm, planes);
338     lf_data->start = start + i * cm->mib_size;
339     lf_data->stop = stop;
340     lf_data->y_only = y_only;
341 
342     // Start loopfiltering
343     if (i == num_workers - 1) {
344       winterface->execute(worker);
345     } else {
346       winterface->launch(worker);
347     }
348   }
349 
350   // Wait till all rows are finished
351   for (i = 0; i < num_workers; ++i) {
352     winterface->sync(&workers[i]);
353   }
354 
355   memset(lf_sync->cur_sb_col, -1, sizeof(*lf_sync->cur_sb_col) * sb_rows);
356   // Filter all the horizontal edges in the whole frame
357   for (i = 0; i < num_workers; ++i) {
358     AVxWorker *const worker = &workers[i];
359     LFWorkerData *const lf_data = &lf_sync->lfdata[i];
360 
361     worker->hook = (AVxWorkerHook)loop_filter_hor_row_worker;
362     worker->data1 = lf_sync;
363     worker->data2 = lf_data;
364 
365     // Loopfilter data
366     av1_loop_filter_data_reset(lf_data, frame, cm, planes);
367     lf_data->start = start + i * cm->mib_size;
368     lf_data->stop = stop;
369     lf_data->y_only = y_only;
370 
371     // Start loopfiltering
372     if (i == num_workers - 1) {
373       winterface->execute(worker);
374     } else {
375       winterface->launch(worker);
376     }
377   }
378 
379   // Wait till all rows are finished
380   for (i = 0; i < num_workers; ++i) {
381     winterface->sync(&workers[i]);
382   }
383 #else   // CONFIG_PARALLEL_DEBLOCKING
384   // Initialize cur_sb_col to -1 for all SB rows.
385   memset(lf_sync->cur_sb_col, -1, sizeof(*lf_sync->cur_sb_col) * sb_rows);
386 
387   for (i = 0; i < num_workers; ++i) {
388     AVxWorker *const worker = &workers[i];
389     LFWorkerData *const lf_data = &lf_sync->lfdata[i];
390 
391     worker->hook = (AVxWorkerHook)loop_filter_row_worker;
392     worker->data1 = lf_sync;
393     worker->data2 = lf_data;
394 
395     // Loopfilter data
396     av1_loop_filter_data_reset(lf_data, frame, cm, planes);
397     lf_data->start = start + i * cm->mib_size;
398     lf_data->stop = stop;
399     lf_data->y_only = y_only;
400 
401     // Start loopfiltering
402     if (i == num_workers - 1) {
403       winterface->execute(worker);
404     } else {
405       winterface->launch(worker);
406     }
407   }
408 
409   // Wait till all rows are finished
410   for (i = 0; i < num_workers; ++i) {
411     winterface->sync(&workers[i]);
412   }
413 #endif  // CONFIG_PARALLEL_DEBLOCKING
414 }
415 
av1_loop_filter_frame_mt(YV12_BUFFER_CONFIG * frame,AV1_COMMON * cm,struct macroblockd_plane * planes,int frame_filter_level,int frame_filter_level_r,int y_only,int partial_frame,AVxWorker * workers,int num_workers,AV1LfSync * lf_sync)416 void av1_loop_filter_frame_mt(YV12_BUFFER_CONFIG *frame, AV1_COMMON *cm,
417                               struct macroblockd_plane *planes,
418                               int frame_filter_level,
419 #if CONFIG_LOOPFILTER_LEVEL
420                               int frame_filter_level_r,
421 #endif
422                               int y_only, int partial_frame, AVxWorker *workers,
423                               int num_workers, AV1LfSync *lf_sync) {
424   int start_mi_row, end_mi_row, mi_rows_to_filter;
425 
426   if (!frame_filter_level) return;
427 
428   start_mi_row = 0;
429   mi_rows_to_filter = cm->mi_rows;
430   if (partial_frame && cm->mi_rows > 8) {
431     start_mi_row = cm->mi_rows >> 1;
432     start_mi_row &= 0xfffffff8;
433     mi_rows_to_filter = AOMMAX(cm->mi_rows / 8, 8);
434   }
435   end_mi_row = start_mi_row + mi_rows_to_filter;
436 #if CONFIG_LOOPFILTER_LEVEL
437   av1_loop_filter_frame_init(cm, frame_filter_level, frame_filter_level_r,
438                              y_only);
439 #else
440   av1_loop_filter_frame_init(cm, frame_filter_level, frame_filter_level);
441 #endif  // CONFIG_LOOPFILTER_LEVEL
442   loop_filter_rows_mt(frame, cm, planes, start_mi_row, end_mi_row, y_only,
443                       workers, num_workers, lf_sync);
444 }
445 
446 // Set up nsync by width.
get_sync_range(int width)447 static INLINE int get_sync_range(int width) {
448   // nsync numbers are picked by testing. For example, for 4k
449   // video, using 4 gives best performance.
450   if (width < 640)
451     return 1;
452   else if (width <= 1280)
453     return 2;
454   else if (width <= 4096)
455     return 4;
456   else
457     return 8;
458 }
459 
460 // Allocate memory for lf row synchronization
av1_loop_filter_alloc(AV1LfSync * lf_sync,AV1_COMMON * cm,int rows,int width,int num_workers)461 void av1_loop_filter_alloc(AV1LfSync *lf_sync, AV1_COMMON *cm, int rows,
462                            int width, int num_workers) {
463   lf_sync->rows = rows;
464 #if CONFIG_MULTITHREAD
465   {
466     int i;
467 
468     CHECK_MEM_ERROR(cm, lf_sync->mutex_,
469                     aom_malloc(sizeof(*lf_sync->mutex_) * rows));
470     if (lf_sync->mutex_) {
471       for (i = 0; i < rows; ++i) {
472         pthread_mutex_init(&lf_sync->mutex_[i], NULL);
473       }
474     }
475 
476     CHECK_MEM_ERROR(cm, lf_sync->cond_,
477                     aom_malloc(sizeof(*lf_sync->cond_) * rows));
478     if (lf_sync->cond_) {
479       for (i = 0; i < rows; ++i) {
480         pthread_cond_init(&lf_sync->cond_[i], NULL);
481       }
482     }
483   }
484 #endif  // CONFIG_MULTITHREAD
485 
486   CHECK_MEM_ERROR(cm, lf_sync->lfdata,
487                   aom_malloc(num_workers * sizeof(*lf_sync->lfdata)));
488   lf_sync->num_workers = num_workers;
489 
490   CHECK_MEM_ERROR(cm, lf_sync->cur_sb_col,
491                   aom_malloc(sizeof(*lf_sync->cur_sb_col) * rows));
492 
493   // Set up nsync.
494   lf_sync->sync_range = get_sync_range(width);
495 }
496 
497 // Deallocate lf synchronization related mutex and data
av1_loop_filter_dealloc(AV1LfSync * lf_sync)498 void av1_loop_filter_dealloc(AV1LfSync *lf_sync) {
499   if (lf_sync != NULL) {
500 #if CONFIG_MULTITHREAD
501     int i;
502 
503     if (lf_sync->mutex_ != NULL) {
504       for (i = 0; i < lf_sync->rows; ++i) {
505         pthread_mutex_destroy(&lf_sync->mutex_[i]);
506       }
507       aom_free(lf_sync->mutex_);
508     }
509     if (lf_sync->cond_ != NULL) {
510       for (i = 0; i < lf_sync->rows; ++i) {
511         pthread_cond_destroy(&lf_sync->cond_[i]);
512       }
513       aom_free(lf_sync->cond_);
514     }
515 #endif  // CONFIG_MULTITHREAD
516     aom_free(lf_sync->lfdata);
517     aom_free(lf_sync->cur_sb_col);
518     // clear the structure as the source of this call may be a resize in which
519     // case this call will be followed by an _alloc() which may fail.
520     av1_zero(*lf_sync);
521   }
522 }
523 
524 // Accumulate frame counts. FRAME_COUNTS consist solely of 'unsigned int'
525 // members, so we treat it as an array, and sum over the whole length.
av1_accumulate_frame_counts(FRAME_COUNTS * acc_counts,FRAME_COUNTS * counts)526 void av1_accumulate_frame_counts(FRAME_COUNTS *acc_counts,
527                                  FRAME_COUNTS *counts) {
528   unsigned int *const acc = (unsigned int *)acc_counts;
529   const unsigned int *const cnt = (unsigned int *)counts;
530 
531   const unsigned int n_counts = sizeof(FRAME_COUNTS) / sizeof(unsigned int);
532   unsigned int i;
533 
534   for (i = 0; i < n_counts; i++) acc[i] += cnt[i];
535 }
536