118 lines
5.4 KiB
C#
118 lines
5.4 KiB
C#
// https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/fast-crc-computation-generic-polynomials-pclmulqdq-paper.pdf
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using ARMeilleure.IntermediateRepresentation;
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using ARMeilleure.Translation;
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using System;
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using System.Diagnostics;
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using static ARMeilleure.Instructions.InstEmitSimdHelper;
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using static ARMeilleure.IntermediateRepresentation.Operand.Factory;
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namespace ARMeilleure.Instructions
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{
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static class InstEmitHashHelper
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{
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public const uint Crc32RevPoly = 0xedb88320;
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public const uint Crc32cRevPoly = 0x82f63b78;
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public static Operand EmitCrc32(ArmEmitterContext context, Operand crc, Operand value, int size, bool castagnoli)
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{
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Debug.Assert(crc.Type.IsInteger() && value.Type.IsInteger());
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Debug.Assert(size >= 0 && size < 4);
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Debug.Assert((size < 3) || (value.Type == OperandType.I64));
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if (castagnoli && Optimizations.UseSse42)
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{
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// The CRC32 instruction does not have an immediate variant, so ensure both inputs are in registers.
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value = (value.Kind == OperandKind.Constant) ? context.Copy(value) : value;
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crc = (crc.Kind == OperandKind.Constant) ? context.Copy(crc) : crc;
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Intrinsic op = size switch
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{
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0 => Intrinsic.X86Crc32_8,
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1 => Intrinsic.X86Crc32_16,
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_ => Intrinsic.X86Crc32,
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};
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return (size == 3) ? context.ConvertI64ToI32(context.AddIntrinsicLong(op, crc, value)) : context.AddIntrinsicInt(op, crc, value);
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}
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else if (Optimizations.UsePclmulqdq)
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{
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return size switch
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{
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3 => EmitCrc32Optimized64(context, crc, value, castagnoli),
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_ => EmitCrc32Optimized(context, crc, value, castagnoli, size),
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};
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}
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else
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{
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string name = (size, castagnoli) switch
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{
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(0, false) => nameof(SoftFallback.Crc32b),
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(1, false) => nameof(SoftFallback.Crc32h),
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(2, false) => nameof(SoftFallback.Crc32w),
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(3, false) => nameof(SoftFallback.Crc32x),
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(0, true) => nameof(SoftFallback.Crc32cb),
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(1, true) => nameof(SoftFallback.Crc32ch),
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(2, true) => nameof(SoftFallback.Crc32cw),
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(3, true) => nameof(SoftFallback.Crc32cx),
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_ => throw new ArgumentOutOfRangeException(nameof(size))
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};
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return context.Call(typeof(SoftFallback).GetMethod(name), crc, value);
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}
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}
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private static Operand EmitCrc32Optimized(ArmEmitterContext context, Operand crc, Operand data, bool castagnoli, int size)
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{
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long mu = castagnoli ? 0x0DEA713F1 : 0x1F7011641; // mu' = floor(x^64/P(x))'
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long polynomial = castagnoli ? 0x105EC76F0 : 0x1DB710641; // P'(x) << 1
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crc = context.VectorInsert(context.VectorZero(), crc, 0);
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switch (size)
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{
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case 0: data = context.VectorInsert8(context.VectorZero(), data, 0); break;
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case 1: data = context.VectorInsert16(context.VectorZero(), data, 0); break;
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case 2: data = context.VectorInsert(context.VectorZero(), data, 0); break;
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}
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int bitsize = 8 << size;
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Operand tmp = context.AddIntrinsic(Intrinsic.X86Pxor, crc, data);
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tmp = context.AddIntrinsic(Intrinsic.X86Psllq, tmp, Const(64 - bitsize));
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tmp = context.AddIntrinsic(Intrinsic.X86Pclmulqdq, tmp, X86GetScalar(context, mu), Const(0));
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tmp = context.AddIntrinsic(Intrinsic.X86Pclmulqdq, tmp, X86GetScalar(context, polynomial), Const(0));
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if (bitsize < 32)
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{
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crc = context.AddIntrinsic(Intrinsic.X86Pslldq, crc, Const((64 - bitsize) / 8));
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tmp = context.AddIntrinsic(Intrinsic.X86Pxor, tmp, crc);
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}
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return context.VectorExtract(OperandType.I32, tmp, 2);
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}
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private static Operand EmitCrc32Optimized64(ArmEmitterContext context, Operand crc, Operand data, bool castagnoli)
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{
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long mu = castagnoli ? 0x0DEA713F1 : 0x1F7011641; // mu' = floor(x^64/P(x))'
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long polynomial = castagnoli ? 0x105EC76F0 : 0x1DB710641; // P'(x) << 1
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crc = context.VectorInsert(context.VectorZero(), crc, 0);
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data = context.VectorInsert(context.VectorZero(), data, 0);
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Operand tmp = context.AddIntrinsic(Intrinsic.X86Pxor, crc, data);
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Operand res = context.AddIntrinsic(Intrinsic.X86Pslldq, tmp, Const(4));
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tmp = context.AddIntrinsic(Intrinsic.X86Pclmulqdq, res, X86GetScalar(context, mu), Const(0));
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tmp = context.AddIntrinsic(Intrinsic.X86Pclmulqdq, tmp, X86GetScalar(context, polynomial), Const(0));
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tmp = context.AddIntrinsic(Intrinsic.X86Pxor, tmp, res);
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tmp = context.AddIntrinsic(Intrinsic.X86Psllq, tmp, Const(32));
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tmp = context.AddIntrinsic(Intrinsic.X86Pclmulqdq, tmp, X86GetScalar(context, mu), Const(1));
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tmp = context.AddIntrinsic(Intrinsic.X86Pclmulqdq, tmp, X86GetScalar(context, polynomial), Const(0));
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return context.VectorExtract(OperandType.I32, tmp, 2);
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}
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}
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}
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