gcc 3.1 warning fix (patch by Felix Buenemann <atmosfear at users.sourceforge.net>)
[ffmpeg.git] / libavcodec / simple_idct.c
1 /*
2  * Simple IDCT
3  *
4  * Copyright (c) 2001 Michael Niedermayer <michaelni@gmx.at>
5  *
6  * This library 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 of the License, or (at your option) any later version.
10  *
11  * This library 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 this library; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  */
20 /*
21   based upon some outcommented c code from mpeg2dec (idct_mmx.c
22   written by Aaron Holtzman <aholtzma@ess.engr.uvic.ca>) 
23  */
24 #include "avcodec.h"
25
26 #include "simple_idct.h"
27
28 #if 0
29 #define W1 2841 /* 2048*sqrt (2)*cos (1*pi/16) */
30 #define W2 2676 /* 2048*sqrt (2)*cos (2*pi/16) */
31 #define W3 2408 /* 2048*sqrt (2)*cos (3*pi/16) */
32 #define W4 2048 /* 2048*sqrt (2)*cos (4*pi/16) */
33 #define W5 1609 /* 2048*sqrt (2)*cos (5*pi/16) */
34 #define W6 1108 /* 2048*sqrt (2)*cos (6*pi/16) */
35 #define W7 565  /* 2048*sqrt (2)*cos (7*pi/16) */
36 #define ROW_SHIFT 8
37 #define COL_SHIFT 17
38 #else
39 #define W1  22725  //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
40 #define W2  21407  //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
41 #define W3  19266  //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
42 #define W4  16383  //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
43 #define W5  12873  //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
44 #define W6  8867   //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
45 #define W7  4520   //cos(i*M_PI/16)*sqrt(2)*(1<<14) + 0.5
46 #define ROW_SHIFT 11
47 #define COL_SHIFT 20 // 6
48 #endif
49
50 /* 8x8 Matrix used to do a trivial (slow) 8 point IDCT */
51 static int coeff[64]={
52         W4, W4, W4, W4, W4, W4, W4, W4,
53         W1, W3, W5, W7,-W7,-W5,-W3,-W1,
54         W2, W6,-W6,-W2,-W2,-W6, W6, W2,
55         W3,-W7,-W1,-W5, W5, W1, W7,-W3,
56         W4,-W4,-W4, W4, W4,-W4,-W4, W4,
57         W5,-W1, W7, W3,-W3,-W7, W1,-W5,
58         W6,-W2, W2,-W6,-W6, W2,-W2, W6,
59         W7,-W5, W3,-W1, W1,-W3, W5,-W7
60 };
61
62 static inline int idctRowCondZ (int16_t * row)
63 {
64         int a0, a1, a2, a3, b0, b1, b2, b3;
65
66         if( !( ((uint32_t*)row)[0]|((uint32_t*)row)[1] |((uint32_t*)row)[2] |((uint32_t*)row)[3])) {
67 /*              row[0] = row[1] = row[2] = row[3] = row[4] =
68                         row[5] = row[6] = row[7] = 0;*/
69                 return 0;
70         }
71
72         if(!( ((uint32_t*)row)[2] |((uint32_t*)row)[3] )){
73                 a0 = W4*row[0] + W2*row[2] + (1<<(ROW_SHIFT-1));
74                 a1 = W4*row[0] + W6*row[2] + (1<<(ROW_SHIFT-1));
75                 a2 = W4*row[0] - W6*row[2] + (1<<(ROW_SHIFT-1));
76                 a3 = W4*row[0] - W2*row[2] + (1<<(ROW_SHIFT-1));
77
78                 b0 = W1*row[1] + W3*row[3];
79                 b1 = W3*row[1] - W7*row[3];
80                 b2 = W5*row[1] - W1*row[3];
81                 b3 = W7*row[1] - W5*row[3];
82         }else{
83                 a0 = W4*row[0] + W2*row[2] + W4*row[4] + W6*row[6] + (1<<(ROW_SHIFT-1));
84                 a1 = W4*row[0] + W6*row[2] - W4*row[4] - W2*row[6] + (1<<(ROW_SHIFT-1));
85                 a2 = W4*row[0] - W6*row[2] - W4*row[4] + W2*row[6] + (1<<(ROW_SHIFT-1));
86                 a3 = W4*row[0] - W2*row[2] + W4*row[4] - W6*row[6] + (1<<(ROW_SHIFT-1));
87
88                 b0 = W1*row[1] + W3*row[3] + W5*row[5] + W7*row[7];
89                 b1 = W3*row[1] - W7*row[3] - W1*row[5] - W5*row[7];
90                 b2 = W5*row[1] - W1*row[3] + W7*row[5] + W3*row[7];
91                 b3 = W7*row[1] - W5*row[3] + W3*row[5] - W1*row[7];
92         }
93
94         row[0] = (a0 + b0) >> ROW_SHIFT;
95         row[1] = (a1 + b1) >> ROW_SHIFT;
96         row[2] = (a2 + b2) >> ROW_SHIFT;
97         row[3] = (a3 + b3) >> ROW_SHIFT;
98         row[4] = (a3 - b3) >> ROW_SHIFT;
99         row[5] = (a2 - b2) >> ROW_SHIFT;
100         row[6] = (a1 - b1) >> ROW_SHIFT;
101         row[7] = (a0 - b0) >> ROW_SHIFT;
102         
103         return 1;
104 }
105
106 #ifdef ARCH_ALPHA
107 /* 0: all entries 0, 1: only first entry nonzero, 2: otherwise  */
108 static inline int idctRowCondDC(int16_t *row)
109 {
110         int_fast32_t a0, a1, a2, a3, b0, b1, b2, b3;
111         uint64_t *lrow = (uint64_t *) row;
112
113         if (lrow[1] == 0) {
114                 if (lrow[0] == 0)
115                         return 0;
116                 if ((lrow[0] & ~0xffffULL) == 0) {
117                         uint64_t v;
118
119                         a0 = W4 * row[0];
120                         a0 += 1 << (ROW_SHIFT - 1);
121                         a0 >>= ROW_SHIFT;
122                         v = (uint16_t) a0;
123                         v += v << 16;
124                         v += v << 32;
125                         lrow[0] = v;
126                         lrow[1] = v;
127
128                         return 1;
129                 }
130         }
131
132         a0 = W4 * row[0];
133         a1 = W4 * row[0];
134         a2 = W4 * row[0];
135         a3 = W4 * row[0];
136
137         if (row[2]) {
138                 a0 += W2 * row[2];
139                 a1 += W6 * row[2];
140                 a2 -= W6 * row[2];
141                 a3 -= W2 * row[2];
142         }
143
144         if (row[4]) {
145                 a0 += W4 * row[4];
146                 a1 -= W4 * row[4];
147                 a2 -= W4 * row[4];
148                 a3 += W4 * row[4];
149         }
150
151         if (row[6]) {
152                 a0 += W6 * row[6];
153                 a1 -= W2 * row[6];
154                 a2 += W2 * row[6];
155                 a3 -= W6 * row[6];
156         }
157
158         a0 += 1 << (ROW_SHIFT - 1);
159         a1 += 1 << (ROW_SHIFT - 1);
160         a2 += 1 << (ROW_SHIFT - 1);
161         a3 += 1 << (ROW_SHIFT - 1);
162
163         if (row[1]) {
164                 b0 = W1 * row[1];
165                 b1 = W3 * row[1];
166                 b2 = W5 * row[1];
167                 b3 = W7 * row[1];
168         } else {
169                 b0 = 0;
170                 b1 = 0;
171                 b2 = 0;
172                 b3 = 0;
173         }
174
175         if (row[3]) {
176                 b0 += W3 * row[3];
177                 b1 -= W7 * row[3];
178                 b2 -= W1 * row[3];
179                 b3 -= W5 * row[3];
180         }
181
182         if (row[5]) {
183                 b0 += W5 * row[5];
184                 b1 -= W1 * row[5];
185                 b2 += W7 * row[5];
186                 b3 += W3 * row[5];
187         }
188
189         if (row[7]) {
190                 b0 += W7 * row[7];
191                 b1 -= W5 * row[7];
192                 b2 += W3 * row[7];
193                 b3 -= W1 * row[7];
194         }
195
196         row[0] = (a0 + b0) >> ROW_SHIFT;
197         row[1] = (a1 + b1) >> ROW_SHIFT;
198         row[2] = (a2 + b2) >> ROW_SHIFT;
199         row[3] = (a3 + b3) >> ROW_SHIFT;
200         row[4] = (a3 - b3) >> ROW_SHIFT;
201         row[5] = (a2 - b2) >> ROW_SHIFT;
202         row[6] = (a1 - b1) >> ROW_SHIFT;
203         row[7] = (a0 - b0) >> ROW_SHIFT;
204
205         return 2;
206 }
207 #else  /* not ARCH_ALPHA */
208 static inline int idctRowCondDC (int16_t * row)
209 {
210         int a0, a1, a2, a3, b0, b1, b2, b3;
211
212         if( !( ((uint32_t*)row)[1] |((uint32_t*)row)[2] |((uint32_t*)row)[3]| row[1])) {
213 //              row[0] = row[1] = row[2] = row[3] = row[4] = row[5] = row[6] = row[7] = row[0]<<3;
214                 uint16_t temp= row[0]<<3;
215                 ((uint32_t*)row)[0]=((uint32_t*)row)[1]=
216                 ((uint32_t*)row)[2]=((uint32_t*)row)[3]= temp + (temp<<16);
217                 return 0;
218         }
219
220         if(!( ((uint32_t*)row)[2] |((uint32_t*)row)[3] )){
221                 a0 = W4*row[0] + W2*row[2] + (1<<(ROW_SHIFT-1));
222                 a1 = W4*row[0] + W6*row[2] + (1<<(ROW_SHIFT-1));
223                 a2 = W4*row[0] - W6*row[2] + (1<<(ROW_SHIFT-1));
224                 a3 = W4*row[0] - W2*row[2] + (1<<(ROW_SHIFT-1));
225
226                 b0 = W1*row[1] + W3*row[3];
227                 b1 = W3*row[1] - W7*row[3];
228                 b2 = W5*row[1] - W1*row[3];
229                 b3 = W7*row[1] - W5*row[3];
230         }else{
231                 a0 = W4*row[0] + W2*row[2] + W4*row[4] + W6*row[6] + (1<<(ROW_SHIFT-1));
232                 a1 = W4*row[0] + W6*row[2] - W4*row[4] - W2*row[6] + (1<<(ROW_SHIFT-1));
233                 a2 = W4*row[0] - W6*row[2] - W4*row[4] + W2*row[6] + (1<<(ROW_SHIFT-1));
234                 a3 = W4*row[0] - W2*row[2] + W4*row[4] - W6*row[6] + (1<<(ROW_SHIFT-1));
235
236                 b0 = W1*row[1] + W3*row[3] + W5*row[5] + W7*row[7];
237                 b1 = W3*row[1] - W7*row[3] - W1*row[5] - W5*row[7];
238                 b2 = W5*row[1] - W1*row[3] + W7*row[5] + W3*row[7];
239                 b3 = W7*row[1] - W5*row[3] + W3*row[5] - W1*row[7];
240         }
241
242         row[0] = (a0 + b0) >> ROW_SHIFT;
243         row[7] = (a0 - b0) >> ROW_SHIFT;
244         row[1] = (a1 + b1) >> ROW_SHIFT;
245         row[6] = (a1 - b1) >> ROW_SHIFT;
246         row[2] = (a2 + b2) >> ROW_SHIFT;
247         row[5] = (a2 - b2) >> ROW_SHIFT;
248         row[3] = (a3 + b3) >> ROW_SHIFT;
249         row[4] = (a3 - b3) >> ROW_SHIFT;
250         
251         return 1;
252 }
253 #endif /* not ARCH_ALPHA */
254
255 static inline void idctCol (int16_t * col)
256 {
257
258 /*
259         if( !(col[8*1] | col[8*2] |col[8*3] |col[8*4] |col[8*5] |col[8*6] | col[8*7])) {
260                 col[8*0] = col[8*1] = col[8*2] = col[8*3] = col[8*4] =
261                         col[8*5] = col[8*6] = col[8*7] = col[8*0]<<3;
262                 return;
263         }*/
264
265         int a0, a1, a2, a3, b0, b1, b2, b3;
266         col[0] += (1<<(COL_SHIFT-1))/W4;
267         a0 = W4*col[8*0] + W2*col[8*2] + W4*col[8*4] + W6*col[8*6];
268         a1 = W4*col[8*0] + W6*col[8*2] - W4*col[8*4] - W2*col[8*6];
269         a2 = W4*col[8*0] - W6*col[8*2] - W4*col[8*4] + W2*col[8*6];
270         a3 = W4*col[8*0] - W2*col[8*2] + W4*col[8*4] - W6*col[8*6];
271
272         b0 = W1*col[8*1] + W3*col[8*3] + W5*col[8*5] + W7*col[8*7];
273         b1 = W3*col[8*1] - W7*col[8*3] - W1*col[8*5] - W5*col[8*7];
274         b2 = W5*col[8*1] - W1*col[8*3] + W7*col[8*5] + W3*col[8*7];
275         b3 = W7*col[8*1] - W5*col[8*3] + W3*col[8*5] - W1*col[8*7];
276
277         col[8*0] = (a0 + b0) >> COL_SHIFT;
278         col[8*7] = (a0 - b0) >> COL_SHIFT;
279         col[8*1] = (a1 + b1) >> COL_SHIFT;
280         col[8*6] = (a1 - b1) >> COL_SHIFT;
281         col[8*2] = (a2 + b2) >> COL_SHIFT;
282         col[8*5] = (a2 - b2) >> COL_SHIFT;
283         col[8*3] = (a3 + b3) >> COL_SHIFT;
284         col[8*4] = (a3 - b3) >> COL_SHIFT;
285 }
286
287 static inline void idctSparseCol (int16_t * col)
288 {
289         int a0, a1, a2, a3, b0, b1, b2, b3;
290         col[0] += (1<<(COL_SHIFT-1))/W4;
291         a0 = W4*col[8*0];
292         a1 = W4*col[8*0];
293         a2 = W4*col[8*0];
294         a3 = W4*col[8*0];
295
296         if(col[8*2]){
297                 a0 +=  + W2*col[8*2];
298                 a1 +=  + W6*col[8*2];
299                 a2 +=  - W6*col[8*2];
300                 a3 +=  - W2*col[8*2];
301         }
302
303         if(col[8*4]){
304                 a0 += + W4*col[8*4];
305                 a1 += - W4*col[8*4];
306                 a2 += - W4*col[8*4];
307                 a3 += + W4*col[8*4];
308         }
309
310         if(col[8*6]){
311                 a0 += + W6*col[8*6];
312                 a1 += - W2*col[8*6];
313                 a2 += + W2*col[8*6];
314                 a3 += - W6*col[8*6];
315         }
316
317         if(col[8*1]){
318                 b0 = W1*col[8*1];
319                 b1 = W3*col[8*1];
320                 b2 = W5*col[8*1];
321                 b3 = W7*col[8*1];
322         }else{
323                 b0 = 
324                 b1 = 
325                 b2 = 
326                 b3 = 0;
327         }
328
329         if(col[8*3]){
330                 b0 += + W3*col[8*3];
331                 b1 += - W7*col[8*3];
332                 b2 += - W1*col[8*3];
333                 b3 += - W5*col[8*3];
334         }
335
336         if(col[8*5]){
337                 b0 += + W5*col[8*5];
338                 b1 += - W1*col[8*5];
339                 b2 += + W7*col[8*5];
340                 b3 += + W3*col[8*5];
341         }
342
343         if(col[8*7]){
344                 b0 += + W7*col[8*7];
345                 b1 += - W5*col[8*7];
346                 b2 += + W3*col[8*7];
347                 b3 += - W1*col[8*7];
348         }
349
350 #ifndef ARCH_ALPHA
351         if(!(b0|b1|b2|b3)){
352                 col[8*0] = (a0) >> COL_SHIFT;
353                 col[8*7] = (a0) >> COL_SHIFT;
354                 col[8*1] = (a1) >> COL_SHIFT;
355                 col[8*6] = (a1) >> COL_SHIFT;
356                 col[8*2] = (a2) >> COL_SHIFT;
357                 col[8*5] = (a2) >> COL_SHIFT;
358                 col[8*3] = (a3) >> COL_SHIFT;
359                 col[8*4] = (a3) >> COL_SHIFT;
360         }else{
361 #endif
362                 col[8*0] = (a0 + b0) >> COL_SHIFT;
363                 col[8*7] = (a0 - b0) >> COL_SHIFT;
364                 col[8*1] = (a1 + b1) >> COL_SHIFT;
365                 col[8*6] = (a1 - b1) >> COL_SHIFT;
366                 col[8*2] = (a2 + b2) >> COL_SHIFT;
367                 col[8*5] = (a2 - b2) >> COL_SHIFT;
368                 col[8*3] = (a3 + b3) >> COL_SHIFT;
369                 col[8*4] = (a3 - b3) >> COL_SHIFT;
370 #ifndef ARCH_ALPHA
371         }
372 #endif
373 }
374
375 static inline void idctSparse2Col (int16_t * col)
376 {
377         int a0, a1, a2, a3, b0, b1, b2, b3;
378         col[0] += (1<<(COL_SHIFT-1))/W4;
379         a0 = W4*col[8*0];
380         a1 = W4*col[8*0];
381         a2 = W4*col[8*0];
382         a3 = W4*col[8*0];
383
384         if(col[8*2]){
385                 a0 +=  + W2*col[8*2];
386                 a1 +=  + W6*col[8*2];
387                 a2 +=  - W6*col[8*2];
388                 a3 +=  - W2*col[8*2];
389         }
390
391         if(col[8*4]){
392                 a0 += + W4*col[8*4];
393                 a1 += - W4*col[8*4];
394                 a2 += - W4*col[8*4];
395                 a3 += + W4*col[8*4];
396         }
397
398         if(col[8*6]){
399                 a0 += + W6*col[8*6];
400                 a1 += - W2*col[8*6];
401                 a2 += + W2*col[8*6];
402                 a3 += - W6*col[8*6];
403         }
404
405         if(col[8*1] || 1){
406                 b0 = W1*col[8*1];
407                 b1 = W3*col[8*1];
408                 b2 = W5*col[8*1];
409                 b3 = W7*col[8*1];
410         }else{
411                 b0 = 
412                 b1 = 
413                 b2 = 
414                 b3 = 0;
415         }
416
417         if(col[8*3]){
418                 b0 += + W3*col[8*3];
419                 b1 += - W7*col[8*3];
420                 b2 += - W1*col[8*3];
421                 b3 += - W5*col[8*3];
422         }
423
424         if(col[8*5]){
425                 b0 += + W5*col[8*5];
426                 b1 += - W1*col[8*5];
427                 b2 += + W7*col[8*5];
428                 b3 += + W3*col[8*5];
429         }
430
431         if(col[8*7]){
432                 b0 += + W7*col[8*7];
433                 b1 += - W5*col[8*7];
434                 b2 += + W3*col[8*7];
435                 b3 += - W1*col[8*7];
436         }
437
438         col[8*0] = (a0 + b0) >> COL_SHIFT;
439         col[8*7] = (a0 - b0) >> COL_SHIFT;
440         col[8*1] = (a1 + b1) >> COL_SHIFT;
441         col[8*6] = (a1 - b1) >> COL_SHIFT;
442         col[8*2] = (a2 + b2) >> COL_SHIFT;
443         col[8*5] = (a2 - b2) >> COL_SHIFT;
444         col[8*3] = (a3 + b3) >> COL_SHIFT;
445         col[8*4] = (a3 - b3) >> COL_SHIFT;
446 }
447
448 #ifdef ARCH_ALPHA
449 /* If all rows but the first one are zero after row transformation,
450    all rows will be identical after column transformation.  */
451 static inline void idctCol2(int16_t *col)
452 {
453         int i;
454         uint64_t l, r;
455         uint64_t *lcol = (uint64_t *) col;
456
457         for (i = 0; i < 8; ++i) {
458                 int a0 = col[0] + (1 << (COL_SHIFT - 1)) / W4;
459
460                 a0 *= W4;
461                 col[0] = a0 >> COL_SHIFT;
462                 ++col;
463         }
464
465         l = lcol[0];
466         r = lcol[1];
467         lcol[ 2] = l; lcol[ 3] = r;
468         lcol[ 4] = l; lcol[ 5] = r;
469         lcol[ 6] = l; lcol[ 7] = r;
470         lcol[ 8] = l; lcol[ 9] = r;
471         lcol[10] = l; lcol[11] = r;
472         lcol[12] = l; lcol[13] = r;
473         lcol[14] = l; lcol[15] = r;
474 }
475 #endif
476
477 void simple_idct (short *block)
478 {
479
480         int i;
481         
482 #if 0
483         int nonZero[8];
484         int buffer[64];
485         int nNonZero=0;
486         
487         idctRowCondDC(block);
488         
489         for(i=1; i<8; i++)
490         {
491                 nonZero[nNonZero]=i;
492                 nNonZero+= idctRowCondZ(block + i*8);
493         }
494         
495         if(nNonZero==0)
496         {
497                 for(i=0; i<8; i++)
498                 {
499                         block[i   ]=
500                         block[i+8 ]=
501                         block[i+16]=
502                         block[i+24]=
503                         block[i+32]=
504                         block[i+40]=
505                         block[i+48]=
506                         block[i+56]= (W4*block[i] + (1<<(COL_SHIFT-1))) >> COL_SHIFT;
507                 }       
508         }
509         else if(nNonZero==1)
510         {
511                 int index= nonZero[0]*8;
512                 for(i=0; i<8; i++)
513                 {
514                         int bias= W4*block[i] + (1<<(COL_SHIFT-1));
515                         int c= block[i + index];
516                         block[i   ]= (c*coeff[index  ] + bias) >> COL_SHIFT;
517                         block[i+8 ]= (c*coeff[index+1] + bias) >> COL_SHIFT;
518                         block[i+16]= (c*coeff[index+2] + bias) >> COL_SHIFT;
519                         block[i+24]= (c*coeff[index+3] + bias) >> COL_SHIFT;
520                         block[i+32]= (c*coeff[index+4] + bias) >> COL_SHIFT;
521                         block[i+40]= (c*coeff[index+5] + bias) >> COL_SHIFT;
522                         block[i+48]= (c*coeff[index+6] + bias) >> COL_SHIFT;
523                         block[i+56]= (c*coeff[index+7] + bias) >> COL_SHIFT;
524                 }       
525         }
526 /*      else if(nNonZero==2)
527         {
528                 int index1= nonZero[0]*8;
529                 int index2= nonZero[1]*8;
530                 for(i=0; i<8; i++)
531                 {
532                         int bias= W4*block[i] + (1<<(COL_SHIFT-1));
533                         int c1= block[i + index1];
534                         int c2= block[i + index2];
535                         block[i   ]= (c1*coeff[index1  ] + c2*coeff[index2  ] + bias) >> COL_SHIFT;
536                         block[i+8 ]= (c1*coeff[index1+1] + c2*coeff[index2+1] + bias) >> COL_SHIFT;
537                         block[i+16]= (c1*coeff[index1+2] + c2*coeff[index2+2] + bias) >> COL_SHIFT;
538                         block[i+24]= (c1*coeff[index1+3] + c2*coeff[index2+3] + bias) >> COL_SHIFT;
539                         block[i+32]= (c1*coeff[index1+4] + c2*coeff[index2+4] + bias) >> COL_SHIFT;
540                         block[i+40]= (c1*coeff[index1+5] + c2*coeff[index2+5] + bias) >> COL_SHIFT;
541                         block[i+48]= (c1*coeff[index1+6] + c2*coeff[index2+6] + bias) >> COL_SHIFT;
542                         block[i+56]= (c1*coeff[index1+7] + c2*coeff[index2+7] + bias) >> COL_SHIFT;
543                 }       
544         }*/
545         else
546         {
547                 for(i=0; i<8; i++)
548                         idctSparse2Col(block + i);
549         }
550 #elif defined(ARCH_ALPHA)
551         int rowsZero = 1;       /* all rows except row 0 zero */
552         int rowsConstant = 1;   /* all rows consist of a constant value */
553
554         for (i = 0; i < 8; i++) {
555                 int sparseness = idctRowCondDC(block + 8 * i);
556
557                 if (i > 0 && sparseness > 0)
558                         rowsZero = 0;
559                 if (sparseness == 2)
560                         rowsConstant = 0;
561         }
562
563         if (rowsZero) {
564                 idctCol2(block);
565         } else if (rowsConstant) {
566                 uint64_t *lblock = (uint64_t *) block;
567
568                 idctSparseCol(block);
569                 for (i = 0; i < 8; i++) {
570                         uint64_t v = (uint16_t) block[i * 8];
571
572                         v += v << 16;
573                         v += v << 32;
574                         lblock[0] = v;
575                         lblock[1] = v;
576                         lblock += 2;
577                 }
578         } else {
579                 for (i = 0; i < 8; i++)
580                         idctSparseCol(block + i);
581         }
582 #else
583         for(i=0; i<8; i++)
584                 idctRowCondDC(block + i*8);
585         
586         for(i=0; i<8; i++)
587                 idctSparseCol(block + i);
588 #endif
589 }
590
591 #undef COL_SHIFT