e4ec23d7ae
Define compiler-independent byte-swap macros and use them instead of
executing 'rev' via inline assembly code with GCC-compatible compilers
or a slow shift-store sequence with Visual C++.
* This produces identical assembly code with:
- 64-bit GCC 8.4.0 (Linux)
- 64-bit GCC 9.3.0 (Linux)
- 64-bit Clang 10.0.0 (Linux)
- 64-bit Clang 10.0.0 (MinGW)
- 64-bit Clang 12.0.0 (Xcode 12.2, macOS)
- 64-bit Clang 12.0.0 (Xcode 12.2, iOS)
* This produces different assembly code with:
- 64-bit GCC 4.9.1 (Linux)
- 32-bit GCC 4.8.2 (Linux)
- 32-bit GCC 8.4.0 (Linux)
- 32-bit GCC 9.3.0 (Linux)
Since the intrinsics implementation of Huffman encoding is not used
by default with these compilers, this is not a concern.
- 32-bit Clang 10.0.0 (Linux)
Verified performance neutrality
Closes #507
40 lines
1.6 KiB
C
40 lines
1.6 KiB
C
/*
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* Copyright (C) 2020, D. R. Commander. All Rights Reserved.
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* Copyright (C) 2020-2021, Arm Limited. All Rights Reserved.
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*/
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#cmakedefine HAVE_VLD1_S16_X3
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#cmakedefine HAVE_VLD1_U16_X2
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#cmakedefine HAVE_VLD1Q_U8_X4
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/* Define compiler-independent count-leading-zeros and byte-swap macros */
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#if defined(_MSC_VER) && !defined(__clang__)
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#define BUILTIN_CLZ(x) _CountLeadingZeros(x)
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#define BUILTIN_CLZLL(x) _CountLeadingZeros64(x)
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#define BUILTIN_BSWAP32(x) _byteswap_ulong(x)
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#define BUILTIN_BSWAP64(x) _byteswap_uint64(x)
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#elif defined(__clang__) || defined(__GNUC__)
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#define BUILTIN_CLZ(x) __builtin_clz(x)
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#define BUILTIN_CLZLL(x) __builtin_clzll(x)
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#define BUILTIN_BSWAP32(x) __builtin_bswap32(x)
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#define BUILTIN_BSWAP64(x) __builtin_bswap64(x)
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#else
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#error "Unknown compiler"
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#endif
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