Files
Aaru/Aaru.Checksums/Adler32/neon.cs

242 lines
10 KiB
C#

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename : neon.cs
// Author(s) : Natalia Portillo <claunia@claunia.com>
// The Chromium Authors
//
// Component : Checksums.
//
// --[ Description ] ----------------------------------------------------------
//
// Compute Adler32 checksum using NEON vectorization.
//
// --[ License ] --------------------------------------------------------------
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2025 Natalia Portillo
// Copyright 2017 The Chromium Authors. All rights reserved.
// ****************************************************************************/
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.Arm;
namespace Aaru.Checksums.Adler32;
static class Neon
{
internal static void Step(ref ushort preSum1, ref ushort preSum2, byte[] buf, uint len)
{
/*
* Split Adler-32 into component sums.
*/
uint s1 = preSum1;
uint s2 = preSum2;
var bufPos = 0;
/*
* Process the data in blocks.
*/
const uint blockSize = 1 << 5;
uint blocks = len / blockSize;
len -= blocks * blockSize;
while(blocks != 0)
{
uint n = Adler32Context.NMax / blockSize; /* The NMAX constraint. */
if(n > blocks) n = blocks;
blocks -= n;
/*
* Process n blocks of data. At most NMAX data bytes can be
* processed before s2 must be reduced modulo ADLER_MODULE.
*/
var vS2 = Vector128.Create(s1 * n, 0, 0, 0);
var vS1 = Vector128.Create(0u, 0, 0, 0);
Vector128<ushort> vColumnSum1 = AdvSimd.DuplicateToVector128((ushort)0);
Vector128<ushort> vColumnSum2 = AdvSimd.DuplicateToVector128((ushort)0);
Vector128<ushort> vColumnSum3 = AdvSimd.DuplicateToVector128((ushort)0);
Vector128<ushort> vColumnSum4 = AdvSimd.DuplicateToVector128((ushort)0);
do
{
/*
* Load 32 input bytes.
*/
var bytes1 = Vector128.Create(buf[bufPos],
buf[bufPos + 1],
buf[bufPos + 2],
buf[bufPos + 3],
buf[bufPos + 4],
buf[bufPos + 5],
buf[bufPos + 6],
buf[bufPos + 7],
buf[bufPos + 8],
buf[bufPos + 9],
buf[bufPos + 10],
buf[bufPos + 11],
buf[bufPos + 12],
buf[bufPos + 13],
buf[bufPos + 14],
buf[bufPos + 15]);
bufPos += 16;
var bytes2 = Vector128.Create(buf[bufPos],
buf[bufPos + 1],
buf[bufPos + 2],
buf[bufPos + 3],
buf[bufPos + 4],
buf[bufPos + 5],
buf[bufPos + 6],
buf[bufPos + 7],
buf[bufPos + 8],
buf[bufPos + 9],
buf[bufPos + 10],
buf[bufPos + 11],
buf[bufPos + 12],
buf[bufPos + 13],
buf[bufPos + 14],
buf[bufPos + 15]);
bufPos += 16;
/*
* Add previous block byte sum to v_s2.
*/
vS2 = AdvSimd.Add(vS2, vS1);
/*
* Horizontally add the bytes for s1.
*/
vS1 = AdvSimd.AddPairwiseWideningAndAdd(vS1,
AdvSimd
.AddPairwiseWideningAndAdd(AdvSimd
.AddPairwiseWidening(bytes1),
bytes2));
/*
* Vertically add the bytes for s2.
*/
vColumnSum1 = AdvSimd.AddWideningLower(vColumnSum1, bytes1.GetLower());
vColumnSum2 = AdvSimd.AddWideningLower(vColumnSum2, bytes1.GetUpper());
vColumnSum3 = AdvSimd.AddWideningLower(vColumnSum3, bytes2.GetLower());
vColumnSum4 = AdvSimd.AddWideningLower(vColumnSum4, bytes2.GetUpper());
} while(--n != 0);
vS2 = AdvSimd.ShiftLeftLogical(vS2, 5);
/*
* Multiply-add bytes by [ 32, 31, 30, ... ] for s2.
*/
vS2 = AdvSimd.MultiplyWideningLowerAndAdd(vS2,
vColumnSum1.GetLower(),
Vector64.Create((ushort)32, 31, 30, 29));
vS2 = AdvSimd.MultiplyWideningLowerAndAdd(vS2,
vColumnSum1.GetUpper(),
Vector64.Create((ushort)28, 27, 26, 25));
vS2 = AdvSimd.MultiplyWideningLowerAndAdd(vS2,
vColumnSum2.GetLower(),
Vector64.Create((ushort)24, 23, 22, 21));
vS2 = AdvSimd.MultiplyWideningLowerAndAdd(vS2,
vColumnSum2.GetUpper(),
Vector64.Create((ushort)20, 19, 18, 17));
vS2 = AdvSimd.MultiplyWideningLowerAndAdd(vS2,
vColumnSum3.GetLower(),
Vector64.Create((ushort)16, 15, 14, 13));
vS2 = AdvSimd.MultiplyWideningLowerAndAdd(vS2,
vColumnSum3.GetUpper(),
Vector64.Create((ushort)12, 11, 10, 9));
vS2 = AdvSimd.MultiplyWideningLowerAndAdd(vS2, vColumnSum4.GetLower(), Vector64.Create((ushort)8, 7, 6, 5));
vS2 = AdvSimd.MultiplyWideningLowerAndAdd(vS2, vColumnSum4.GetUpper(), Vector64.Create((ushort)4, 3, 2, 1));
/*
* Sum epi32 ints v_s1(s2) and accumulate in s1(s2).
*/
Vector64<uint> sum1 = AdvSimd.AddPairwise(vS1.GetLower(), vS1.GetUpper());
Vector64<uint> sum2 = AdvSimd.AddPairwise(vS2.GetLower(), vS2.GetUpper());
Vector64<uint> s1S2 = AdvSimd.AddPairwise(sum1, sum2);
s1 += AdvSimd.Extract(s1S2, 0);
s2 += AdvSimd.Extract(s1S2, 1);
/*
* Reduce.
*/
s1 %= Adler32Context.AdlerModule;
s2 %= Adler32Context.AdlerModule;
}
/*
* Handle leftover data.
*/
if(len != 0)
{
if(len >= 16)
{
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
s2 += s1 += buf[bufPos++];
len -= 16;
}
while(len-- != 0) s2 += s1 += buf[bufPos++];
if(s1 >= Adler32Context.AdlerModule) s1 -= Adler32Context.AdlerModule;
s2 %= Adler32Context.AdlerModule;
}
/*
* Return the recombined sums.
*/
preSum1 = (ushort)(s1 & 0xFFFF);
preSum2 = (ushort)(s2 & 0xFFFF);
}
}