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Merge branch 'mirror' into vdpau
[FFMpeg-mirror/ffmpeg-vdpau.git] / libavcodec / cabac.h
blobe012727054e694f3a5541136adc407ed189de8e3
1 /*
2 * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file cabac.h
24 * Context Adaptive Binary Arithmetic Coder.
25 */
26
27 #ifndef AVCODEC_CABAC_H
28 #define AVCODEC_CABAC_H
29
30 #include "bitstream.h"
31
32 //#undef NDEBUG
33 #include <assert.h>
34 #include "libavutil/x86_cpu.h"
35
36 #define CABAC_BITS 16
37 #define CABAC_MASK ((1<<CABAC_BITS)-1)
38 #define BRANCHLESS_CABAC_DECODER 1
39 //#define ARCH_X86_DISABLED 1
40
41 typedef struct CABACContext{
42 int low;
43 int range;
44 int outstanding_count;
45 #ifdef STRICT_LIMITS
46 int symCount;
47 #endif
48 const uint8_t *bytestream_start;
49 const uint8_t *bytestream;
50 const uint8_t *bytestream_end;
51 PutBitContext pb;
52 }CABACContext;
53
54 extern uint8_t ff_h264_mlps_state[4*64];
55 extern uint8_t ff_h264_lps_range[4*2*64]; ///< rangeTabLPS
56 extern uint8_t ff_h264_mps_state[2*64]; ///< transIdxMPS
57 extern uint8_t ff_h264_lps_state[2*64]; ///< transIdxLPS
58 extern const uint8_t ff_h264_norm_shift[512];
59
60
61 void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size);
62 void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size);
63 void ff_init_cabac_states(CABACContext *c);
64
65
66 static inline void put_cabac_bit(CABACContext *c, int b){
67 put_bits(&c->pb, 1, b);
68 for(;c->outstanding_count; c->outstanding_count--){
69 put_bits(&c->pb, 1, 1-b);
70 }
71 }
72
73 static inline void renorm_cabac_encoder(CABACContext *c){
74 while(c->range < 0x100){
75 //FIXME optimize
76 if(c->low<0x100){
77 put_cabac_bit(c, 0);
78 }else if(c->low<0x200){
79 c->outstanding_count++;
80 c->low -= 0x100;
81 }else{
82 put_cabac_bit(c, 1);
83 c->low -= 0x200;
84 }
85
86 c->range+= c->range;
87 c->low += c->low;
88 }
89 }
90
91 #ifdef TEST
92 static void put_cabac(CABACContext *c, uint8_t * const state, int bit){
93 int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + *state];
94
95 if(bit == ((*state)&1)){
96 c->range -= RangeLPS;
97 *state= ff_h264_mps_state[*state];
98 }else{
99 c->low += c->range - RangeLPS;
100 c->range = RangeLPS;
101 *state= ff_h264_lps_state[*state];
102 }
103
104 renorm_cabac_encoder(c);
105
106 #ifdef STRICT_LIMITS
107 c->symCount++;
108 #endif
109 }
110
111 static void put_cabac_static(CABACContext *c, int RangeLPS, int bit){
112 assert(c->range > RangeLPS);
113
114 if(!bit){
115 c->range -= RangeLPS;
116 }else{
117 c->low += c->range - RangeLPS;
118 c->range = RangeLPS;
119 }
120
121 renorm_cabac_encoder(c);
122
123 #ifdef STRICT_LIMITS
124 c->symCount++;
125 #endif
126 }
127
128 /**
129 * @param bit 0 -> write zero bit, !=0 write one bit
130 */
131 static void put_cabac_bypass(CABACContext *c, int bit){
132 c->low += c->low;
133
134 if(bit){
135 c->low += c->range;
136 }
137 //FIXME optimize
138 if(c->low<0x200){
139 put_cabac_bit(c, 0);
140 }else if(c->low<0x400){
141 c->outstanding_count++;
142 c->low -= 0x200;
143 }else{
144 put_cabac_bit(c, 1);
145 c->low -= 0x400;
146 }
147
148 #ifdef STRICT_LIMITS
149 c->symCount++;
150 #endif
151 }
152
153 /**
154 *
155 * @return the number of bytes written
156 */
157 static int put_cabac_terminate(CABACContext *c, int bit){
158 c->range -= 2;
159
160 if(!bit){
161 renorm_cabac_encoder(c);
162 }else{
163 c->low += c->range;
164 c->range= 2;
165
166 renorm_cabac_encoder(c);
167
168 assert(c->low <= 0x1FF);
169 put_cabac_bit(c, c->low>>9);
170 put_bits(&c->pb, 2, ((c->low>>7)&3)|1);
171
172 flush_put_bits(&c->pb); //FIXME FIXME FIXME XXX wrong
173 }
174
175 #ifdef STRICT_LIMITS
176 c->symCount++;
177 #endif
178
179 return (put_bits_count(&c->pb)+7)>>3;
180 }
181
182 /**
183 * put (truncated) unary binarization.
184 */
185 static void put_cabac_u(CABACContext *c, uint8_t * state, int v, int max, int max_index, int truncated){
186 int i;
187
188 assert(v <= max);
189
190 #if 1
191 for(i=0; i<v; i++){
192 put_cabac(c, state, 1);
193 if(i < max_index) state++;
194 }
195 if(truncated==0 || v<max)
196 put_cabac(c, state, 0);
197 #else
198 if(v <= max_index){
199 for(i=0; i<v; i++){
200 put_cabac(c, state+i, 1);
201 }
202 if(truncated==0 || v<max)
203 put_cabac(c, state+i, 0);
204 }else{
205 for(i=0; i<=max_index; i++){
206 put_cabac(c, state+i, 1);
207 }
208 for(; i<v; i++){
209 put_cabac(c, state+max_index, 1);
210 }
211 if(truncated==0 || v<max)
212 put_cabac(c, state+max_index, 0);
213 }
214 #endif
215 }
216
217 /**
218 * put unary exp golomb k-th order binarization.
219 */
220 static void put_cabac_ueg(CABACContext *c, uint8_t * state, int v, int max, int is_signed, int k, int max_index){
221 int i;
222
223 if(v==0)
224 put_cabac(c, state, 0);
225 else{
226 const int sign= v < 0;
227
228 if(is_signed) v= FFABS(v);
229
230 if(v<max){
231 for(i=0; i<v; i++){
232 put_cabac(c, state, 1);
233 if(i < max_index) state++;
234 }
235
236 put_cabac(c, state, 0);
237 }else{
238 int m= 1<<k;
239
240 for(i=0; i<max; i++){
241 put_cabac(c, state, 1);
242 if(i < max_index) state++;
243 }
244
245 v -= max;
246 while(v >= m){ //FIXME optimize
247 put_cabac_bypass(c, 1);
248 v-= m;
249 m+= m;
250 }
251 put_cabac_bypass(c, 0);
252 while(m>>=1){
253 put_cabac_bypass(c, v&m);
254 }
255 }
256
257 if(is_signed)
258 put_cabac_bypass(c, sign);
259 }
260 }
261 #endif /* TEST */
262
263 static void refill(CABACContext *c){
264 #if CABAC_BITS == 16
265 c->low+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
266 #else
267 c->low+= c->bytestream[0]<<1;
268 #endif
269 c->low -= CABAC_MASK;
270 c->bytestream+= CABAC_BITS/8;
271 }
272
273 #if ! ( defined(ARCH_X86) && defined(HAVE_7REGS) && defined(HAVE_EBX_AVAILABLE) && !defined(BROKEN_RELOCATIONS) )
274 static void refill2(CABACContext *c){
275 int i, x;
276
277 x= c->low ^ (c->low-1);
278 i= 7 - ff_h264_norm_shift[x>>(CABAC_BITS-1)];
279
280 x= -CABAC_MASK;
281
282 #if CABAC_BITS == 16
283 x+= (c->bytestream[0]<<9) + (c->bytestream[1]<<1);
284 #else
285 x+= c->bytestream[0]<<1;
286 #endif
287
288 c->low += x<<i;
289 c->bytestream+= CABAC_BITS/8;
290 }
291 #endif
292
293 static inline void renorm_cabac_decoder(CABACContext *c){
294 while(c->range < 0x100){
295 c->range+= c->range;
296 c->low+= c->low;
297 if(!(c->low & CABAC_MASK))
298 refill(c);
299 }
300 }
301
302 static inline void renorm_cabac_decoder_once(CABACContext *c){
303 #ifdef ARCH_X86_DISABLED
304 int temp;
305 #if 0
306 //P3:683 athlon:475
307 __asm__(
308 "lea -0x100(%0), %2 \n\t"
309 "shr $31, %2 \n\t" //FIXME 31->63 for x86-64
310 "shl %%cl, %0 \n\t"
311 "shl %%cl, %1 \n\t"
312 : "+r"(c->range), "+r"(c->low), "+c"(temp)
313 );
314 #elif 0
315 //P3:680 athlon:474
316 __asm__(
317 "cmp $0x100, %0 \n\t"
318 "setb %%cl \n\t" //FIXME 31->63 for x86-64
319 "shl %%cl, %0 \n\t"
320 "shl %%cl, %1 \n\t"
321 : "+r"(c->range), "+r"(c->low), "+c"(temp)
322 );
323 #elif 1
324 int temp2;
325 //P3:665 athlon:517
326 __asm__(
327 "lea -0x100(%0), %%eax \n\t"
328 "cltd \n\t"
329 "mov %0, %%eax \n\t"
330 "and %%edx, %0 \n\t"
331 "and %1, %%edx \n\t"
332 "add %%eax, %0 \n\t"
333 "add %%edx, %1 \n\t"
334 : "+r"(c->range), "+r"(c->low), "+a"(temp), "+d"(temp2)
335 );
336 #elif 0
337 int temp2;
338 //P3:673 athlon:509
339 __asm__(
340 "cmp $0x100, %0 \n\t"
341 "sbb %%edx, %%edx \n\t"
342 "mov %0, %%eax \n\t"
343 "and %%edx, %0 \n\t"
344 "and %1, %%edx \n\t"
345 "add %%eax, %0 \n\t"
346 "add %%edx, %1 \n\t"
347 : "+r"(c->range), "+r"(c->low), "+a"(temp), "+d"(temp2)
348 );
349 #else
350 int temp2;
351 //P3:677 athlon:511
352 __asm__(
353 "cmp $0x100, %0 \n\t"
354 "lea (%0, %0), %%eax \n\t"
355 "lea (%1, %1), %%edx \n\t"
356 "cmovb %%eax, %0 \n\t"
357 "cmovb %%edx, %1 \n\t"
358 : "+r"(c->range), "+r"(c->low), "+a"(temp), "+d"(temp2)
359 );
360 #endif
361 #else
362 //P3:675 athlon:476
363 int shift= (uint32_t)(c->range - 0x100)>>31;
364 c->range<<= shift;
365 c->low <<= shift;
366 #endif
367 if(!(c->low & CABAC_MASK))
368 refill(c);
369 }
370
371 static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){
372 //FIXME gcc generates duplicate load/stores for c->low and c->range
373 #define LOW "0"
374 #define RANGE "4"
375 #ifdef ARCH_X86_64
376 #define BYTESTART "16"
377 #define BYTE "24"
378 #define BYTEEND "32"
379 #else
380 #define BYTESTART "12"
381 #define BYTE "16"
382 #define BYTEEND "20"
383 #endif
384 #if defined(ARCH_X86) && defined(HAVE_7REGS) && defined(HAVE_EBX_AVAILABLE) && !defined(BROKEN_RELOCATIONS)
385 int bit;
386
387 #ifndef BRANCHLESS_CABAC_DECODER
388 __asm__ volatile(
389 "movzbl (%1), %0 \n\t"
390 "movl "RANGE "(%2), %%ebx \n\t"
391 "movl "RANGE "(%2), %%edx \n\t"
392 "andl $0xC0, %%ebx \n\t"
393 "movzbl "MANGLE(ff_h264_lps_range)"(%0, %%ebx, 2), %%esi\n\t"
394 "movl "LOW "(%2), %%ebx \n\t"
395 //eax:state ebx:low, edx:range, esi:RangeLPS
396 "subl %%esi, %%edx \n\t"
397 "movl %%edx, %%ecx \n\t"
398 "shll $17, %%ecx \n\t"
399 "cmpl %%ecx, %%ebx \n\t"
400 " ja 1f \n\t"
401
402 #if 1
403 //athlon:4067 P3:4110
404 "lea -0x100(%%edx), %%ecx \n\t"
405 "shr $31, %%ecx \n\t"
406 "shl %%cl, %%edx \n\t"
407 "shl %%cl, %%ebx \n\t"
408 #else
409 //athlon:4057 P3:4130
410 "cmp $0x100, %%edx \n\t" //FIXME avoidable
411 "setb %%cl \n\t"
412 "shl %%cl, %%edx \n\t"
413 "shl %%cl, %%ebx \n\t"
414 #endif
415 "movzbl "MANGLE(ff_h264_mps_state)"(%0), %%ecx \n\t"
416 "movb %%cl, (%1) \n\t"
417 //eax:state ebx:low, edx:range, esi:RangeLPS
418 "test %%bx, %%bx \n\t"
419 " jnz 2f \n\t"
420 "mov "BYTE "(%2), %%"REG_S" \n\t"
421 "subl $0xFFFF, %%ebx \n\t"
422 "movzwl (%%"REG_S"), %%ecx \n\t"
423 "bswap %%ecx \n\t"
424 "shrl $15, %%ecx \n\t"
425 "add $2, %%"REG_S" \n\t"
426 "addl %%ecx, %%ebx \n\t"
427 "mov %%"REG_S", "BYTE "(%2) \n\t"
428 "jmp 2f \n\t"
429 "1: \n\t"
430 //eax:state ebx:low, edx:range, esi:RangeLPS
431 "subl %%ecx, %%ebx \n\t"
432 "movl %%esi, %%edx \n\t"
433 "movzbl " MANGLE(ff_h264_norm_shift) "(%%esi), %%ecx \n\t"
434 "shll %%cl, %%ebx \n\t"
435 "shll %%cl, %%edx \n\t"
436 "movzbl "MANGLE(ff_h264_lps_state)"(%0), %%ecx \n\t"
437 "movb %%cl, (%1) \n\t"
438 "add $1, %0 \n\t"
439 "test %%bx, %%bx \n\t"
440 " jnz 2f \n\t"
441
442 "mov "BYTE "(%2), %%"REG_c" \n\t"
443 "movzwl (%%"REG_c"), %%esi \n\t"
444 "bswap %%esi \n\t"
445 "shrl $15, %%esi \n\t"
446 "subl $0xFFFF, %%esi \n\t"
447 "add $2, %%"REG_c" \n\t"
448 "mov %%"REG_c", "BYTE "(%2) \n\t"
449
450 "leal -1(%%ebx), %%ecx \n\t"
451 "xorl %%ebx, %%ecx \n\t"
452 "shrl $15, %%ecx \n\t"
453 "movzbl " MANGLE(ff_h264_norm_shift) "(%%ecx), %%ecx \n\t"
454 "neg %%ecx \n\t"
455 "add $7, %%ecx \n\t"
456
457 "shll %%cl , %%esi \n\t"
458 "addl %%esi, %%ebx \n\t"
459 "2: \n\t"
460 "movl %%edx, "RANGE "(%2) \n\t"
461 "movl %%ebx, "LOW "(%2) \n\t"
462 :"=&a"(bit) //FIXME this is fragile gcc either runs out of registers or miscompiles it (for example if "+a"(bit) or "+m"(*state) is used
463 :"r"(state), "r"(c)
464 : "%"REG_c, "%ebx", "%edx", "%"REG_S, "memory"
465 );
466 bit&=1;
467 #else /* BRANCHLESS_CABAC_DECODER */
468
469
470 #if defined HAVE_FAST_CMOV
471 #define BRANCHLESS_GET_CABAC_UPDATE(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\
472 "mov "tmp" , %%ecx \n\t"\
473 "shl $17 , "tmp" \n\t"\
474 "cmp "low" , "tmp" \n\t"\
475 "cmova %%ecx , "range" \n\t"\
476 "sbb %%ecx , %%ecx \n\t"\
477 "and %%ecx , "tmp" \n\t"\
478 "sub "tmp" , "low" \n\t"\
479 "xor %%ecx , "ret" \n\t"
480 #else /* HAVE_FAST_CMOV */
481 #define BRANCHLESS_GET_CABAC_UPDATE(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\
482 "mov "tmp" , %%ecx \n\t"\
483 "shl $17 , "tmp" \n\t"\
484 "sub "low" , "tmp" \n\t"\
485 "sar $31 , "tmp" \n\t" /*lps_mask*/\
486 "sub %%ecx , "range" \n\t" /*RangeLPS - range*/\
487 "and "tmp" , "range" \n\t" /*(RangeLPS - range)&lps_mask*/\
488 "add %%ecx , "range" \n\t" /*new range*/\
489 "shl $17 , %%ecx \n\t"\
490 "and "tmp" , %%ecx \n\t"\
491 "sub %%ecx , "low" \n\t"\
492 "xor "tmp" , "ret" \n\t"
493 #endif /* HAVE_FAST_CMOV */
494
495
496 #define BRANCHLESS_GET_CABAC(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\
497 "movzbl "statep" , "ret" \n\t"\
498 "mov "range" , "tmp" \n\t"\
499 "and $0xC0 , "range" \n\t"\
500 "movzbl "MANGLE(ff_h264_lps_range)"("ret", "range", 2), "range" \n\t"\
501 "sub "range" , "tmp" \n\t"\
502 BRANCHLESS_GET_CABAC_UPDATE(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\
503 "movzbl " MANGLE(ff_h264_norm_shift) "("range"), %%ecx \n\t"\
504 "shl %%cl , "range" \n\t"\
505 "movzbl "MANGLE(ff_h264_mlps_state)"+128("ret"), "tmp" \n\t"\
506 "mov "tmpbyte" , "statep" \n\t"\
507 "shl %%cl , "low" \n\t"\
508 "test "lowword" , "lowword" \n\t"\
509 " jnz 1f \n\t"\
510 "mov "BYTE"("cabac"), %%"REG_c" \n\t"\
511 "movzwl (%%"REG_c") , "tmp" \n\t"\
512 "bswap "tmp" \n\t"\
513 "shr $15 , "tmp" \n\t"\
514 "sub $0xFFFF , "tmp" \n\t"\
515 "add $2 , %%"REG_c" \n\t"\
516 "mov %%"REG_c" , "BYTE "("cabac") \n\t"\
517 "lea -1("low") , %%ecx \n\t"\
518 "xor "low" , %%ecx \n\t"\
519 "shr $15 , %%ecx \n\t"\
520 "movzbl " MANGLE(ff_h264_norm_shift) "(%%ecx), %%ecx \n\t"\
521 "neg %%ecx \n\t"\
522 "add $7 , %%ecx \n\t"\
523 "shl %%cl , "tmp" \n\t"\
524 "add "tmp" , "low" \n\t"\
525 "1: \n\t"
526
527 __asm__ volatile(
528 "movl "RANGE "(%2), %%esi \n\t"
529 "movl "LOW "(%2), %%ebx \n\t"
530 BRANCHLESS_GET_CABAC("%0", "%2", "(%1)", "%%ebx", "%%bx", "%%esi", "%%edx", "%%dl")
531 "movl %%esi, "RANGE "(%2) \n\t"
532 "movl %%ebx, "LOW "(%2) \n\t"
533
534 :"=&a"(bit)
535 :"r"(state), "r"(c)
536 : "%"REG_c, "%ebx", "%edx", "%esi", "memory"
537 );
538 bit&=1;
539 #endif /* BRANCHLESS_CABAC_DECODER */
540 #else /* defined(ARCH_X86) && defined(HAVE_7REGS) && defined(HAVE_EBX_AVAILABLE) && !defined(BROKEN_RELOCATIONS) */
541 int s = *state;
542 int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
543 int bit, lps_mask av_unused;
544
545 c->range -= RangeLPS;
546 #ifndef BRANCHLESS_CABAC_DECODER
547 if(c->low < (c->range<<(CABAC_BITS+1))){
548 bit= s&1;
549 *state= ff_h264_mps_state[s];
550 renorm_cabac_decoder_once(c);
551 }else{
552 bit= ff_h264_norm_shift[RangeLPS];
553 c->low -= (c->range<<(CABAC_BITS+1));
554 *state= ff_h264_lps_state[s];
555 c->range = RangeLPS<<bit;
556 c->low <<= bit;
557 bit= (s&1)^1;
558
559 if(!(c->low & CABAC_MASK)){
560 refill2(c);
561 }
562 }
563 #else /* BRANCHLESS_CABAC_DECODER */
564 lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;
565
566 c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;
567 c->range += (RangeLPS - c->range) & lps_mask;
568
569 s^=lps_mask;
570 *state= (ff_h264_mlps_state+128)[s];
571 bit= s&1;
572
573 lps_mask= ff_h264_norm_shift[c->range];
574 c->range<<= lps_mask;
575 c->low <<= lps_mask;
576 if(!(c->low & CABAC_MASK))
577 refill2(c);
578 #endif /* BRANCHLESS_CABAC_DECODER */
579 #endif /* defined(ARCH_X86) && defined(HAVE_7REGS) && defined(HAVE_EBX_AVAILABLE) && !defined(BROKEN_RELOCATIONS) */
580 return bit;
581 }
582
583 static int av_noinline av_unused get_cabac_noinline(CABACContext *c, uint8_t * const state){
584 return get_cabac_inline(c,state);
585 }
586
587 static int av_unused get_cabac(CABACContext *c, uint8_t * const state){
588 return get_cabac_inline(c,state);
589 }
590
591 static int av_unused get_cabac_bypass(CABACContext *c){
592 #if 0 //not faster
593 int bit;
594 __asm__ volatile(
595 "movl "RANGE "(%1), %%ebx \n\t"
596 "movl "LOW "(%1), %%eax \n\t"
597 "shl $17, %%ebx \n\t"
598 "add %%eax, %%eax \n\t"
599 "sub %%ebx, %%eax \n\t"
600 "cltd \n\t"
601 "and %%edx, %%ebx \n\t"
602 "add %%ebx, %%eax \n\t"
603 "test %%ax, %%ax \n\t"
604 " jnz 1f \n\t"
605 "movl "BYTE "(%1), %%"REG_b" \n\t"
606 "subl $0xFFFF, %%eax \n\t"
607 "movzwl (%%"REG_b"), %%ecx \n\t"
608 "bswap %%ecx \n\t"
609 "shrl $15, %%ecx \n\t"
610 "addl $2, %%"REG_b" \n\t"
611 "addl %%ecx, %%eax \n\t"
612 "movl %%"REG_b", "BYTE "(%1) \n\t"
613 "1: \n\t"
614 "movl %%eax, "LOW "(%1) \n\t"
615
616 :"=&d"(bit)
617 :"r"(c)
618 : "%eax", "%"REG_b, "%ecx", "memory"
619 );
620 return bit+1;
621 #else
622 int range;
623 c->low += c->low;
624
625 if(!(c->low & CABAC_MASK))
626 refill(c);
627
628 range= c->range<<(CABAC_BITS+1);
629 if(c->low < range){
630 return 0;
631 }else{
632 c->low -= range;
633 return 1;
634 }
635 #endif
636 }
637
638
639 static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
640 #if defined(ARCH_X86) && !(defined(PIC) && defined(__GNUC__))
641 __asm__ volatile(
642 "movl "RANGE "(%1), %%ebx \n\t"
643 "movl "LOW "(%1), %%eax \n\t"
644 "shl $17, %%ebx \n\t"
645 "add %%eax, %%eax \n\t"
646 "sub %%ebx, %%eax \n\t"
647 "cltd \n\t"
648 "and %%edx, %%ebx \n\t"
649 "add %%ebx, %%eax \n\t"
650 "xor %%edx, %%ecx \n\t"
651 "sub %%edx, %%ecx \n\t"
652 "test %%ax, %%ax \n\t"
653 " jnz 1f \n\t"
654 "mov "BYTE "(%1), %%"REG_b" \n\t"
655 "subl $0xFFFF, %%eax \n\t"
656 "movzwl (%%"REG_b"), %%edx \n\t"
657 "bswap %%edx \n\t"
658 "shrl $15, %%edx \n\t"
659 "add $2, %%"REG_b" \n\t"
660 "addl %%edx, %%eax \n\t"
661 "mov %%"REG_b", "BYTE "(%1) \n\t"
662 "1: \n\t"
663 "movl %%eax, "LOW "(%1) \n\t"
664
665 :"+c"(val)
666 :"r"(c)
667 : "%eax", "%"REG_b, "%edx", "memory"
668 );
669 return val;
670 #else
671 int range, mask;
672 c->low += c->low;
673
674 if(!(c->low & CABAC_MASK))
675 refill(c);
676
677 range= c->range<<(CABAC_BITS+1);
678 c->low -= range;
679 mask= c->low >> 31;
680 range &= mask;
681 c->low += range;
682 return (val^mask)-mask;
683 #endif
684 }
685
686 /**
687 *
688 * @return the number of bytes read or 0 if no end
689 */
690 static int av_unused get_cabac_terminate(CABACContext *c){
691 c->range -= 2;
692 if(c->low < c->range<<(CABAC_BITS+1)){
693 renorm_cabac_decoder_once(c);
694 return 0;
695 }else{
696 return c->bytestream - c->bytestream_start;
697 }
698 }
699
700 #if 0
701 /**
702 * Get (truncated) unary binarization.
703 */
704 static int get_cabac_u(CABACContext *c, uint8_t * state, int max, int max_index, int truncated){
705 int i;
706
707 for(i=0; i<max; i++){
708 if(get_cabac(c, state)==0)
709 return i;
710
711 if(i< max_index) state++;
712 }
713
714 return truncated ? max : -1;
715 }
716
717 /**
718 * get unary exp golomb k-th order binarization.
719 */
720 static int get_cabac_ueg(CABACContext *c, uint8_t * state, int max, int is_signed, int k, int max_index){
721 int i, v;
722 int m= 1<<k;
723
724 if(get_cabac(c, state)==0)
725 return 0;
726
727 if(0 < max_index) state++;
728
729 for(i=1; i<max; i++){
730 if(get_cabac(c, state)==0){
731 if(is_signed && get_cabac_bypass(c)){
732 return -i;
733 }else
734 return i;
735 }
736
737 if(i < max_index) state++;
738 }
739
740 while(get_cabac_bypass(c)){
741 i+= m;
742 m+= m;
743 }
744
745 v=0;
746 while(m>>=1){
747 v+= v + get_cabac_bypass(c);
748 }
749 i += v;
750
751 if(is_signed && get_cabac_bypass(c)){
752 return -i;
753 }else
754 return i;
755 }
756 #endif /* 0 */
757
758 #endif /* AVCODEC_CABAC_H */
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