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246 lines
11 KiB
C#
246 lines
11 KiB
C#
// /***************************************************************************
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// Aaru Data Preservation Suite
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// ----------------------------------------------------------------------------
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//
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// Filename : neon.cs
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// Author(s) : Natalia Portillo <claunia@claunia.com>
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// The Chromium Authors
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//
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// Component : Checksums.
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//
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// --[ Description ] ----------------------------------------------------------
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//
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// Compute Fletcher32 checksum using NEON vectorization.
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//
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// --[ License ] --------------------------------------------------------------
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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 are
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// met:
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//
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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
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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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
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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// ----------------------------------------------------------------------------
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// Copyright © 2011-2025 Natalia Portillo
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// Copyright 2017 The Chromium Authors. All rights reserved.
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// ****************************************************************************/
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using System.Runtime.Intrinsics;
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using System.Runtime.Intrinsics.Arm;
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namespace Aaru.Checksums.Fletcher32;
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static class Neon
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{
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internal static void Step(ref ushort preSum1, ref ushort preSum2, byte[] buf, uint len)
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{
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/*
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* Split Fletcher-32 into component sums.
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*/
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uint s1 = preSum1;
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uint s2 = preSum2;
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var bufPos = 0;
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/*
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* Process the data in blocks.
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*/
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const uint block_Size = 1 << 5;
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uint blocks = len / block_Size;
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len -= blocks * block_Size;
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while(blocks != 0)
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{
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uint n = Fletcher32Context.Nmax / block_Size; /* The NMAX constraint. */
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if(n > blocks) n = blocks;
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blocks -= n;
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/*
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* Process n blocks of data. At most NMAX data bytes can be
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* processed before s2 must be reduced modulo FLETCHER_MODULE.
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*/
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var v_S2 = Vector128.Create(s1 * n, 0, 0, 0);
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var v_S1 = Vector128.Create(0u, 0, 0, 0);
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Vector128<ushort> v_Column_Sum_1 = AdvSimd.DuplicateToVector128((ushort)0);
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Vector128<ushort> v_Column_Sum_2 = AdvSimd.DuplicateToVector128((ushort)0);
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Vector128<ushort> v_Column_Sum_3 = AdvSimd.DuplicateToVector128((ushort)0);
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Vector128<ushort> v_Column_Sum_4 = AdvSimd.DuplicateToVector128((ushort)0);
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do
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{
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/*
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* Load 32 input bytes.
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*/
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var bytes1 = Vector128.Create(buf[bufPos],
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buf[bufPos + 1],
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buf[bufPos + 2],
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buf[bufPos + 3],
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buf[bufPos + 4],
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buf[bufPos + 5],
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buf[bufPos + 6],
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buf[bufPos + 7],
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buf[bufPos + 8],
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buf[bufPos + 9],
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buf[bufPos + 10],
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buf[bufPos + 11],
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buf[bufPos + 12],
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buf[bufPos + 13],
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buf[bufPos + 14],
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buf[bufPos + 15]);
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bufPos += 16;
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var bytes2 = Vector128.Create(buf[bufPos],
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buf[bufPos + 1],
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buf[bufPos + 2],
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buf[bufPos + 3],
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buf[bufPos + 4],
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buf[bufPos + 5],
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buf[bufPos + 6],
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buf[bufPos + 7],
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buf[bufPos + 8],
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buf[bufPos + 9],
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buf[bufPos + 10],
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buf[bufPos + 11],
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buf[bufPos + 12],
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buf[bufPos + 13],
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buf[bufPos + 14],
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buf[bufPos + 15]);
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bufPos += 16;
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/*
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* Add previous block byte sum to v_s2.
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*/
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v_S2 = AdvSimd.Add(v_S2, v_S1);
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/*
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* Horizontally add the bytes for s1.
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*/
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v_S1 = AdvSimd.AddPairwiseWideningAndAdd(v_S1,
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AdvSimd
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.AddPairwiseWideningAndAdd(AdvSimd
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.AddPairwiseWidening(bytes1),
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bytes2));
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/*
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* Vertically add the bytes for s2.
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*/
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v_Column_Sum_1 = AdvSimd.AddWideningLower(v_Column_Sum_1, bytes1.GetLower());
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v_Column_Sum_2 = AdvSimd.AddWideningLower(v_Column_Sum_2, bytes1.GetUpper());
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v_Column_Sum_3 = AdvSimd.AddWideningLower(v_Column_Sum_3, bytes2.GetLower());
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v_Column_Sum_4 = AdvSimd.AddWideningLower(v_Column_Sum_4, bytes2.GetUpper());
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} while(--n != 0);
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v_S2 = AdvSimd.ShiftLeftLogical(v_S2, 5);
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/*
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* Multiply-add bytes by [ 32, 31, 30, ... ] for s2.
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*/
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v_S2 = AdvSimd.MultiplyWideningLowerAndAdd(v_S2,
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v_Column_Sum_1.GetLower(),
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Vector64.Create((ushort)32, 31, 30, 29));
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v_S2 = AdvSimd.MultiplyWideningLowerAndAdd(v_S2,
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v_Column_Sum_1.GetUpper(),
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Vector64.Create((ushort)28, 27, 26, 25));
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v_S2 = AdvSimd.MultiplyWideningLowerAndAdd(v_S2,
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v_Column_Sum_2.GetLower(),
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Vector64.Create((ushort)24, 23, 22, 21));
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v_S2 = AdvSimd.MultiplyWideningLowerAndAdd(v_S2,
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v_Column_Sum_2.GetUpper(),
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Vector64.Create((ushort)20, 19, 18, 17));
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v_S2 = AdvSimd.MultiplyWideningLowerAndAdd(v_S2,
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v_Column_Sum_3.GetLower(),
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Vector64.Create((ushort)16, 15, 14, 13));
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v_S2 = AdvSimd.MultiplyWideningLowerAndAdd(v_S2,
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v_Column_Sum_3.GetUpper(),
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Vector64.Create((ushort)12, 11, 10, 9));
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v_S2 = AdvSimd.MultiplyWideningLowerAndAdd(v_S2,
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v_Column_Sum_4.GetLower(),
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Vector64.Create((ushort)8, 7, 6, 5));
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v_S2 = AdvSimd.MultiplyWideningLowerAndAdd(v_S2,
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v_Column_Sum_4.GetUpper(),
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Vector64.Create((ushort)4, 3, 2, 1));
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/*
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* Sum epi32 ints v_s1(s2) and accumulate in s1(s2).
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*/
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Vector64<uint> sum1 = AdvSimd.AddPairwise(v_S1.GetLower(), v_S1.GetUpper());
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Vector64<uint> sum2 = AdvSimd.AddPairwise(v_S2.GetLower(), v_S2.GetUpper());
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Vector64<uint> s1S2 = AdvSimd.AddPairwise(sum1, sum2);
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s1 += AdvSimd.Extract(s1S2, 0);
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s2 += AdvSimd.Extract(s1S2, 1);
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/*
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* Reduce.
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*/
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s1 %= Fletcher32Context.FletcherModule;
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s2 %= Fletcher32Context.FletcherModule;
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}
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/*
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* Handle leftover data.
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*/
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if(len != 0)
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{
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if(len >= 16)
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{
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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s2 += s1 += buf[bufPos++];
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len -= 16;
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}
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while(len-- != 0) s2 += s1 += buf[bufPos++];
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if(s1 >= Fletcher32Context.FletcherModule) s1 -= Fletcher32Context.FletcherModule;
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s2 %= Fletcher32Context.FletcherModule;
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}
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/*
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* Return the recombined sums.
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*/
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preSum1 = (ushort)(s1 & 0xFFFF);
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preSum2 = (ushort)(s2 & 0xFFFF);
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}
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} |