1 /**
2 * VP5 and VP6 compatible video decoder (arith decoder)
3 *
4 * Copyright (C) 2006 Aurelien Jacobs <aurel@gnuage.org>
5 * Copyright (C) 2010 Eli Friedman
6 *
7 * This file is part of FFmpeg.
8 *
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24 #ifndef AVCODEC_X86_VP56_ARITH_H
25 #define AVCODEC_X86_VP56_ARITH_H
26
27 #if HAVE_INLINE_ASM && HAVE_FAST_CMOV && HAVE_6REGS
28 #include "libavutil/attributes.h"
29
30 #define vp56_rac_get_prob vp56_rac_get_prob
vp56_rac_get_prob(VP56RangeCoder * c,uint8_t prob)31 static av_always_inline int vp56_rac_get_prob(VP56RangeCoder *c, uint8_t prob)
32 {
33 unsigned int code_word = vp56_rac_renorm(c);
34 unsigned int low = 1 + (((c->high - 1) * prob) >> 8);
35 unsigned int low_shift = low << 16;
36 int bit = 0;
37 c->code_word = code_word;
38
39 __asm__(
40 "subl %4, %1 \n\t"
41 "subl %3, %2 \n\t"
42 "setae %b0 \n\t"
43 "cmovb %4, %1 \n\t"
44 "cmovb %5, %2 \n\t"
45 : "+q"(bit), "+&r"(c->high), "+&r"(c->code_word)
46 : "r"(low_shift), "r"(low), "r"(code_word)
47 );
48
49 return bit;
50 }
51 #endif
52
53 #endif /* AVCODEC_X86_VP56_ARITH_H */
54