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82c71913e4
This adds a hand-optimized assembly version for get_cabac much like the existing one, but it works if the table offsets are RIP-relative. Compared to the non-RIP-relative version this adds 2 lea instructions and it needs one extra register. There is a surprisingly large performance improvement over the c version (more so than the generated assembly seems to suggest) just in get_cabac, I measured roughly 40% faster for get_cabac on a K8. However, overall the difference is not that big, I measured roughly 5% on a test clip on a K8 and a Core2. Hopefully it still compiles on x86 32bit... Now that only one table is used, there's some chance even darwin as compiles this (apparently the label arithmetic used previously doesn't work if it involves symbols defined in a different file, thanks to Ronald S. Bultje for helping me with this). Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
224 lines
11 KiB
C
224 lines
11 KiB
C
/*
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* Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVCODEC_X86_CABAC_H
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#define AVCODEC_X86_CABAC_H
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#include "libavcodec/cabac.h"
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#include "libavutil/attributes.h"
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#include "libavutil/x86_cpu.h"
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#include "libavutil/internal.h"
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#include "config.h"
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#ifdef BROKEN_RELOCATIONS
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#define TABLES_ARG , "r"(tables)
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#if HAVE_FAST_CMOV
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#define BRANCHLESS_GET_CABAC_UPDATE(ret, retq, low, range, tmp) \
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"cmp "low" , "tmp" \n\t"\
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"cmova %%ecx , "range" \n\t"\
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"sbb %%rcx , %%rcx \n\t"\
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"and %%ecx , "tmp" \n\t"\
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"xor %%rcx , "retq" \n\t"\
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"sub "tmp" , "low" \n\t"
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#else /* HAVE_FAST_CMOV */
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#define BRANCHLESS_GET_CABAC_UPDATE(ret, retq, low, range, tmp) \
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/* P4 Prescott has crappy cmov,sbb,64bit shift so avoid them */ \
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"sub "low" , "tmp" \n\t"\
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"sar $31 , "tmp" \n\t"\
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"sub %%ecx , "range" \n\t"\
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"and "tmp" , "range" \n\t"\
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"add %%ecx , "range" \n\t"\
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"shl $17 , %%ecx \n\t"\
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"and "tmp" , %%ecx \n\t"\
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"sub %%ecx , "low" \n\t"\
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"xor "tmp" , "ret" \n\t"\
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"movslq "ret" , "retq" \n\t"
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#endif /* HAVE_FAST_CMOV */
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#define BRANCHLESS_GET_CABAC(ret, retq, statep, low, lowword, range, rangeq, tmp, tmpbyte, byte, end, norm_off, lps_off, mlps_off, tables) \
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"movzbl "statep" , "ret" \n\t"\
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"mov "range" , "tmp" \n\t"\
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"and $0xC0 , "range" \n\t"\
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"lea ("ret", "range", 2), %%ecx \n\t"\
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"movzbl "lps_off"("tables", %%rcx), "range" \n\t"\
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"sub "range" , "tmp" \n\t"\
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"mov "tmp" , %%ecx \n\t"\
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"shl $17 , "tmp" \n\t"\
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BRANCHLESS_GET_CABAC_UPDATE(ret, retq, low, range, tmp) \
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"movzbl "norm_off"("tables", "rangeq"), %%ecx \n\t"\
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"shl %%cl , "range" \n\t"\
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"movzbl "mlps_off"+128("tables", "retq"), "tmp" \n\t"\
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"shl %%cl , "low" \n\t"\
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"mov "tmpbyte" , "statep" \n\t"\
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"test "lowword" , "lowword" \n\t"\
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"jnz 2f \n\t"\
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"mov "byte" , %%"REG_c" \n\t"\
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"add"OPSIZE" $2 , "byte" \n\t"\
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"movzwl (%%"REG_c") , "tmp" \n\t"\
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"lea -1("low") , %%ecx \n\t"\
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"xor "low" , %%ecx \n\t"\
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"shr $15 , %%ecx \n\t"\
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"bswap "tmp" \n\t"\
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"shr $15 , "tmp" \n\t"\
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"movzbl "norm_off"("tables", %%rcx), %%ecx \n\t"\
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"sub $0xFFFF , "tmp" \n\t"\
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"neg %%ecx \n\t"\
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"add $7 , %%ecx \n\t"\
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"shl %%cl , "tmp" \n\t"\
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"add "tmp" , "low" \n\t"\
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"2: \n\t"
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#else /* BROKEN_RELOCATIONS */
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#define TABLES_ARG
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#define RIP_ARG
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#if HAVE_FAST_CMOV
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#define BRANCHLESS_GET_CABAC_UPDATE(ret, low, range, tmp)\
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"mov "tmp" , %%ecx \n\t"\
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"shl $17 , "tmp" \n\t"\
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"cmp "low" , "tmp" \n\t"\
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"cmova %%ecx , "range" \n\t"\
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"sbb %%ecx , %%ecx \n\t"\
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"and %%ecx , "tmp" \n\t"\
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"xor %%ecx , "ret" \n\t"\
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"sub "tmp" , "low" \n\t"
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#else /* HAVE_FAST_CMOV */
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#define BRANCHLESS_GET_CABAC_UPDATE(ret, low, range, tmp)\
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"mov "tmp" , %%ecx \n\t"\
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"shl $17 , "tmp" \n\t"\
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"sub "low" , "tmp" \n\t"\
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"sar $31 , "tmp" \n\t" /*lps_mask*/\
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"sub %%ecx , "range" \n\t" /*RangeLPS - range*/\
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"and "tmp" , "range" \n\t" /*(RangeLPS - range)&lps_mask*/\
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"add %%ecx , "range" \n\t" /*new range*/\
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"shl $17 , %%ecx \n\t"\
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"and "tmp" , %%ecx \n\t"\
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"sub %%ecx , "low" \n\t"\
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"xor "tmp" , "ret" \n\t"
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#endif /* HAVE_FAST_CMOV */
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#define BRANCHLESS_GET_CABAC(ret, retq, statep, low, lowword, range, rangeq, tmp, tmpbyte, byte, end, norm_off, lps_off, mlps_off, tables) \
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"movzbl "statep" , "ret" \n\t"\
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"mov "range" , "tmp" \n\t"\
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"and $0xC0 , "range" \n\t"\
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"movzbl "MANGLE(ff_h264_cabac_tables)"+"lps_off"("ret", "range", 2), "range" \n\t"\
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"sub "range" , "tmp" \n\t"\
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BRANCHLESS_GET_CABAC_UPDATE(ret, low, range, tmp) \
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"movzbl "MANGLE(ff_h264_cabac_tables)"+"norm_off"("range"), %%ecx \n\t"\
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"shl %%cl , "range" \n\t"\
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"movzbl "MANGLE(ff_h264_cabac_tables)"+"mlps_off"+128("ret"), "tmp" \n\t"\
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"shl %%cl , "low" \n\t"\
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"mov "tmpbyte" , "statep" \n\t"\
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"test "lowword" , "lowword" \n\t"\
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" jnz 2f \n\t"\
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"mov "byte" , %%"REG_c" \n\t"\
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"add"OPSIZE" $2 , "byte" \n\t"\
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"movzwl (%%"REG_c") , "tmp" \n\t"\
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"lea -1("low") , %%ecx \n\t"\
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"xor "low" , %%ecx \n\t"\
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"shr $15 , %%ecx \n\t"\
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"bswap "tmp" \n\t"\
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"shr $15 , "tmp" \n\t"\
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"movzbl "MANGLE(ff_h264_cabac_tables)"+"norm_off"(%%ecx), %%ecx \n\t"\
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"sub $0xFFFF , "tmp" \n\t"\
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"neg %%ecx \n\t"\
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"add $7 , %%ecx \n\t"\
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"shl %%cl , "tmp" \n\t"\
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"add "tmp" , "low" \n\t"\
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"2: \n\t"
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#endif /* BROKEN_RELOCATIONS */
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#if HAVE_7REGS && !(defined(__i386) && defined(__clang__) && (__clang_major__<2 || (__clang_major__==2 && __clang_minor__<10)))\
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&& !(defined(__i386) && !defined(__clang__) && defined(__llvm__) && __GNUC__==4 && __GNUC_MINOR__==2 && __GNUC_PATCHLEVEL__<=1)
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#define get_cabac_inline get_cabac_inline_x86
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static av_always_inline int get_cabac_inline_x86(CABACContext *c,
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uint8_t *const state)
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{
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int bit, tmp;
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#ifdef BROKEN_RELOCATIONS
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void *tables;
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__asm__ volatile(
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"lea "MANGLE(ff_h264_cabac_tables)", %0 \n\t"
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: "=&r"(tables)
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);
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#endif
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__asm__ volatile(
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BRANCHLESS_GET_CABAC("%0", "%q0", "(%4)", "%1", "%w1",
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"%2", "%q2", "%3", "%b3",
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"%a6(%5)", "%a7(%5)", "%a8", "%a9", "%a10", "%11")
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: "=&r"(bit), "+&r"(c->low), "+&r"(c->range), "=&q"(tmp)
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: "r"(state), "r"(c),
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"i"(offsetof(CABACContext, bytestream)),
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"i"(offsetof(CABACContext, bytestream_end)),
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"i"(H264_NORM_SHIFT_OFFSET),
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"i"(H264_LPS_RANGE_OFFSET),
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"i"(H264_MLPS_STATE_OFFSET) TABLES_ARG
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: "%"REG_c, "memory"
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);
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return bit & 1;
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}
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#endif /* HAVE_7REGS */
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#define get_cabac_bypass_sign get_cabac_bypass_sign_x86
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static av_always_inline int get_cabac_bypass_sign_x86(CABACContext *c, int val)
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{
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x86_reg tmp;
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__asm__ volatile(
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"movl %a6(%2), %k1 \n\t"
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"movl %a3(%2), %%eax \n\t"
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"shl $17, %k1 \n\t"
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"add %%eax, %%eax \n\t"
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"sub %k1, %%eax \n\t"
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"cltd \n\t"
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"and %%edx, %k1 \n\t"
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"add %k1, %%eax \n\t"
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"xor %%edx, %%ecx \n\t"
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"sub %%edx, %%ecx \n\t"
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"test %%ax, %%ax \n\t"
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"jnz 1f \n\t"
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"mov %a4(%2), %1 \n\t"
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"subl $0xFFFF, %%eax \n\t"
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"movzwl (%1), %%edx \n\t"
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"bswap %%edx \n\t"
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"shrl $15, %%edx \n\t"
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"add $2, %1 \n\t"
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"addl %%edx, %%eax \n\t"
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"mov %1, %a4(%2) \n\t"
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"1: \n\t"
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"movl %%eax, %a3(%2) \n\t"
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: "+c"(val), "=&r"(tmp)
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: "r"(c),
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"i"(offsetof(CABACContext, low)),
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"i"(offsetof(CABACContext, bytestream)),
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"i"(offsetof(CABACContext, bytestream_end)),
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"i"(offsetof(CABACContext, range))
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: "%eax", "%edx", "memory"
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);
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return val;
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}
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#endif /* AVCODEC_X86_CABAC_H */
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