зеркало из https://github.com/mozilla/gecko-dev.git
93 строки
3.7 KiB
C
93 строки
3.7 KiB
C
/* Copyright (c) 2003-2008 Timothy B. Terriberry
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Copyright (c) 2008 Xiph.Org Foundation */
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/*
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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- Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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- Neither the name of Internet Society, IETF or IETF Trust, nor the
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names of specific contributors, may be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
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OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*Some common macros for potential platform-specific optimization.*/
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#include "opus_types.h"
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#include <math.h>
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#include <limits.h>
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#include "arch.h"
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#if !defined(_ecintrin_H)
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# define _ecintrin_H (1)
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/*Some specific platforms may have optimized intrinsic or inline assembly
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versions of these functions which can substantially improve performance.
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We define macros for them to allow easy incorporation of these non-ANSI
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features.*/
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/*Modern gcc (4.x) can compile the naive versions of min and max with cmov if
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given an appropriate architecture, but the branchless bit-twiddling versions
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are just as fast, and do not require any special target architecture.
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Earlier gcc versions (3.x) compiled both code to the same assembly
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instructions, because of the way they represented ((_b)>(_a)) internally.*/
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# define EC_MINI(_a,_b) ((_a)+(((_b)-(_a))&-((_b)<(_a))))
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/*Count leading zeros.
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This macro should only be used for implementing ec_ilog(), if it is defined.
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All other code should use EC_ILOG() instead.*/
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#if defined(_MSC_VER)
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# include <intrin.h>
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/*In _DEBUG mode this is not an intrinsic by default.*/
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# pragma intrinsic(_BitScanReverse)
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static __inline int ec_bsr(unsigned long _x){
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unsigned long ret;
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_BitScanReverse(&ret,_x);
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return (int)ret;
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}
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# define EC_CLZ0 (1)
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# define EC_CLZ(_x) (-ec_bsr(_x))
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#elif defined(ENABLE_TI_DSPLIB)
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# include "dsplib.h"
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# define EC_CLZ0 (31)
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# define EC_CLZ(_x) (_lnorm(_x))
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#elif __GNUC_PREREQ(3,4)
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# if INT_MAX>=2147483647
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# define EC_CLZ0 ((int)sizeof(unsigned)*CHAR_BIT)
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# define EC_CLZ(_x) (__builtin_clz(_x))
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# elif LONG_MAX>=2147483647L
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# define EC_CLZ0 ((int)sizeof(unsigned long)*CHAR_BIT)
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# define EC_CLZ(_x) (__builtin_clzl(_x))
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# endif
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#endif
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#if defined(EC_CLZ)
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/*Note that __builtin_clz is not defined when _x==0, according to the gcc
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documentation (and that of the BSR instruction that implements it on x86).
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The majority of the time we can never pass it zero.
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When we need to, it can be special cased.*/
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# define EC_ILOG(_x) (EC_CLZ0-EC_CLZ(_x))
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#else
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int ec_ilog(opus_uint32 _v);
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# define EC_ILOG(_x) (ec_ilog(_x))
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#endif
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#endif
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