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AdvSimd support for System.Text.Unicode.Utf16Utility.GetPointerToFirstInvalidChar #39050

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Merged
carlossanlop merged 9 commits into from
Jul 16, 2020
Merged

AdvSimd support for System.Text.Unicode.Utf16Utility.GetPointerToFirstInvalidChar #39050

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11e1c42
AdvSimd support for System.Text.Unicode.Utf16Utility.GetPointerToFirs…
carlossanlop Jul 10, 2020
7591589
Move using directive outside #if.
carlossanlop Jul 10, 2020
b6b07fc
Change overloads
carlossanlop Jul 11, 2020
b754c31
UIn64 in Arm64MoveMask
carlossanlop Jul 13, 2020
e7e6295
Build error implicit conversion fix
carlossanlop Jul 13, 2020
38ddb49
Rename method and use simpler version
carlossanlop Jul 14, 2020
2bf42cf
Use ShiftRightArithmetic instead of CompareEqual + And.
carlossanlop Jul 14, 2020
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Remove unnecessary comment
carlossanlop Jul 14, 2020
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Add missing shims causing Linux build to fail
carlossanlop Jul 15, 2020
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85 changes: 72 additions & 13 deletions src/libraries/System.Private.CoreLib/src/System/Text/Unicode/Utf16Utility.Validation.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.Arm;
using System.Runtime.Intrinsics.X86;
using System.Numerics;

Expand Down Expand Up @@ -78,7 +79,7 @@ static Utf16Utility()
long tempUtf8CodeUnitCountAdjustment = 0;
int tempScalarCountAdjustment = 0;

if (Sse2.IsSupported)
if (AdvSimd.Arm64.IsSupported || Sse2.IsSupported)
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{
if (inputLength >= Vector128<ushort>.Count)
{
Expand All @@ -87,17 +88,32 @@ static Utf16Utility()
Vector128<short> vector8800 = Vector128.Create(unchecked((short)0x8800));
Vector128<ushort> vectorZero = Vector128<ushort>.Zero;


Vector128<byte> initialMask = Vector128.Create((ushort)0x1001).AsByte();
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Vector128<byte> mostSignficantBitMask = Vector128.Create((byte)0x80);
do
{
Vector128<ushort> utf16Data = Sse2.LoadVector128((ushort*)pInputBuffer); // unaligned
Vector128<ushort> utf16Data;
if (AdvSimd.Arm64.IsSupported)
{
utf16Data = AdvSimd.LoadVector128((ushort*)pInputBuffer); // unaligned
}
else
{
utf16Data = Sse2.LoadVector128((ushort*)pInputBuffer); // unaligned
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}
uint mask;

Vector128<ushort> charIsNonAscii;
if (Sse41.IsSupported)
{
// Sets the 0x0080 bit of each element in 'charIsNonAscii' if the corresponding
// input was 0x0080 <= [value]. (i.e., [value] is non-ASCII.)

// Sets the 0x0080 bit of each element in 'charIsNonAscii' if the corresponding
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// input was 0x0080 <= [value]. (i.e., [value] is non-ASCII.)
if (AdvSimd.Arm64.IsSupported)
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{
charIsNonAscii = AdvSimd.Min(utf16Data, vector0080);
}
else if (Sse41.IsSupported)
{
charIsNonAscii = Sse41.Min(utf16Data, vector0080);
}
else
Expand All @@ -111,16 +127,33 @@ static Utf16Utility()

#if DEBUG
// Quick check to ensure we didn't accidentally set the 0x8000 bit of any element.
uint debugMask = (uint)Sse2.MoveMask(charIsNonAscii.AsByte());
uint debugMask;
if (AdvSimd.Arm64.IsSupported)
{
debugMask = Arm64MoveMask(charIsNonAscii.AsByte(), initialMask, mostSignficantBitMask);
}
else
{
debugMask = (uint)Sse2.MoveMask(charIsNonAscii.AsByte());
}
Debug.Assert((debugMask & 0b_1010_1010_1010_1010) == 0, "Shouldn't have set the 0x8000 bit of any element in 'charIsNonAscii'.");
#endif // DEBUG

// Sets the 0x8080 bits of each element in 'charIsNonAscii' if the corresponding
// input was 0x0800 <= [value]. This also handles the missing range a few lines above.

Vector128<ushort> charIsThreeByteUtf8Encoded = Sse2.Subtract(vectorZero, Sse2.ShiftRightLogical(utf16Data, 11));
Vector128<ushort> charIsThreeByteUtf8Encoded;
if (AdvSimd.IsSupported)
{
charIsThreeByteUtf8Encoded = AdvSimd.Subtract(vectorZero, AdvSimd.ShiftRightLogical(utf16Data, 11));
mask = Arm64MoveMask(AdvSimd.Or(charIsNonAscii, charIsThreeByteUtf8Encoded).AsByte(), initialMask, mostSignficantBitMask);
}
else
{
charIsThreeByteUtf8Encoded = Sse2.Subtract(vectorZero, Sse2.ShiftRightLogical(utf16Data, 11));
mask = (uint)Sse2.MoveMask(Sse2.Or(charIsNonAscii, charIsThreeByteUtf8Encoded).AsByte());
}

mask = (uint)Sse2.MoveMask(Sse2.Or(charIsNonAscii, charIsThreeByteUtf8Encoded).AsByte());

// Each even bit of mask will be 1 only if the char was >= 0x0080,
// and each odd bit of mask will be 1 only if the char was >= 0x0800.
Expand Down Expand Up @@ -151,9 +184,16 @@ static Utf16Utility()
// Surrogates need to be special-cased for two reasons: (a) we need
// to account for the fact that we over-counted in the addition above;
// and (b) they require separate validation.

utf16Data = Sse2.Add(utf16Data, vectorA800);
mask = (uint)Sse2.MoveMask(Sse2.CompareLessThan(utf16Data.AsInt16(), vector8800).AsByte());
if (AdvSimd.Arm64.IsSupported)
{
utf16Data = AdvSimd.Add(utf16Data, vectorA800);
mask = Arm64MoveMask(AdvSimd.CompareLessThan(utf16Data.AsInt16(), vector8800).AsByte(), initialMask, mostSignficantBitMask);
}
else
{
utf16Data = Sse2.Add(utf16Data, vectorA800);
mask = (uint)Sse2.MoveMask(Sse2.CompareLessThan(utf16Data.AsInt16(), vector8800).AsByte());
}

if (mask != 0)
{
Expand All @@ -178,7 +218,15 @@ static Utf16Utility()
// Since 'mask' already has 00 in these positions (since the corresponding char
// wasn't a surrogate), "mask AND mask2 == 00" holds for these positions.

uint mask2 = (uint)Sse2.MoveMask(Sse2.ShiftRightLogical(utf16Data, 3).AsByte());
uint mask2;
if (AdvSimd.Arm64.IsSupported)
{
mask2 = Arm64MoveMask(AdvSimd.ShiftRightLogical(utf16Data, 3).AsByte(), initialMask, mostSignficantBitMask);
}
else
{
mask2 = (uint)Sse2.MoveMask(Sse2.ShiftRightLogical(utf16Data, 3).AsByte());
}

// 'lowSurrogatesMask' has its bits occur in pairs:
// - 01 if the corresponding char was a low surrogate char,
Expand Down Expand Up @@ -433,5 +481,16 @@ static Utf16Utility()
scalarCountAdjustment = tempScalarCountAdjustment;
return pInputBuffer;
}

[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static uint Arm64MoveMask(Vector128<byte> value, Vector128<byte> initialMask, Vector128<byte> mostSignficantBitMask)
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{
Debug.Assert(AdvSimd.Arm64.IsSupported);

Vector128<byte> mostSignificantBitIsSet = AdvSimd.CompareEqual(AdvSimd.And(value, mostSignficantBitMask), mostSignficantBitMask);
Vector128<byte> extractedBits = AdvSimd.And(mostSignificantBitIsSet, initialMask);
extractedBits = AdvSimd.Arm64.AddPairwise(extractedBits, extractedBits);
return extractedBits.AsUInt16().ToScalar();
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}
}
}