aac5773f
 hucm
功能基本完成，接口待打磨
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/**
* VP5 and VP6 compatible video decoder (arith decoder)
*
* Copyright (C) 2006 Aurelien Jacobs <aurel@gnuage.org>
* Copyright (C) 2010 Eli Friedman
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVCODEC_X86_VP56_ARITH_H
#define AVCODEC_X86_VP56_ARITH_H
#if HAVE_INLINE_ASM && HAVE_FAST_CMOV && HAVE_6REGS
#define vp56_rac_get_prob vp56_rac_get_prob
static av_always_inline int vp56_rac_get_prob(VP56RangeCoder *c, uint8_t prob)
{
unsigned int code_word = vp56_rac_renorm(c);
unsigned int low = 1 + (((c->high - 1) * prob) >> 8);
unsigned int low_shift = low << 16;
int bit = 0;
c->code_word = code_word;
__asm__(
"subl %4, %1 \n\t"
"subl %3, %2 \n\t"
"setae %b0 \n\t"
"cmovb %4, %1 \n\t"
"cmovb %5, %2 \n\t"
: "+q"(bit), "+&r"(c->high), "+&r"(c->code_word)
: "r"(low_shift), "r"(low), "r"(code_word)
);
return bit;
}
#endif
#endif /* AVCODEC_X86_VP56_ARITH_H */
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