Skip to content

Refactor NonAscii bit mask usage #43537

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Oct 19, 2020
Merged

Refactor NonAscii bit mask usage #43537

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
d81cf0f
Refactor NonAscii bit mask usage
eerhardt Oct 16, 2020
eb11e3b
Refactor code so the Vector128 is declared inline.
eerhardt Oct 17, 2020
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
67 changes: 38 additions & 29 deletions src/libraries/System.Private.CoreLib/src/System/Text/Unicode/Utf8Utility.Validation.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -121,50 +121,59 @@ internal static unsafe partial class Utf8Utility
byte* pInputBufferFinalPosAtWhichCanSafelyLoop = pFinalPosWhereCanReadDWordFromInputBuffer - 3 * sizeof(uint); // can safely read 4 DWORDs here
nuint trailingZeroCount;

Vector128<byte> bitMask128 = BitConverter.IsLittleEndian ?
Vector128.Create((ushort)0x1001).AsByte() :
Vector128.Create((ushort)0x0110).AsByte();

do
// pInputBuffer is 32-bit aligned but not necessary 128-bit aligned, so we're
// going to perform an unaligned load. We don't necessarily care about aligning
// this because we pessimistically assume we'll encounter non-ASCII data at some
// point in the not-too-distant future (otherwise we would've stayed entirely
// within the all-ASCII vectorized code at the entry to this method).
if (AdvSimd.Arm64.IsSupported && BitConverter.IsLittleEndian)
{
// pInputBuffer is 32-bit aligned but not necessary 128-bit aligned, so we're
// going to perform an unaligned load. We don't necessarily care about aligning
// this because we pessimistically assume we'll encounter non-ASCII data at some
// point in the not-too-distant future (otherwise we would've stayed entirely
// within the all-ASCII vectorized code at the entry to this method).
if (AdvSimd.Arm64.IsSupported && BitConverter.IsLittleEndian)
// declare bitMask128 inside of the AdvSimd.Arm64.IsSupported check
// so it gets removed on non-Arm64 builds.
Vector128<byte> bitMask128 = BitConverter.IsLittleEndian ?
Vector128.Create((ushort)0x1001).AsByte() :
Vector128.Create((ushort)0x0110).AsByte();
do
{
ulong mask = GetNonAsciiBytes(AdvSimd.LoadVector128(pInputBuffer), bitMask128);
if (mask != 0)
{
trailingZeroCount = (nuint)BitOperations.TrailingZeroCount(mask) >> 2;
goto LoopTerminatedEarlyDueToNonAsciiData;
}
}
else if (Sse2.IsSupported)

pInputBuffer += 4 * sizeof(uint); // consumed 4 DWORDs
} while (pInputBuffer <= pInputBufferFinalPosAtWhichCanSafelyLoop);
}
else
{
do
{
uint mask = (uint)Sse2.MoveMask(Sse2.LoadVector128(pInputBuffer));
if (mask != 0)
if (Sse2.IsSupported)
{
trailingZeroCount = (nuint)BitOperations.TrailingZeroCount(mask);
goto LoopTerminatedEarlyDueToNonAsciiData;
uint mask = (uint)Sse2.MoveMask(Sse2.LoadVector128(pInputBuffer));
if (mask != 0)
{
trailingZeroCount = (nuint)BitOperations.TrailingZeroCount(mask);
goto LoopTerminatedEarlyDueToNonAsciiData;
}
}
}
else
{
if (!ASCIIUtility.AllBytesInUInt32AreAscii(((uint*)pInputBuffer)[0] | ((uint*)pInputBuffer)[1]))
else
{
goto LoopTerminatedEarlyDueToNonAsciiDataInFirstPair;
}
if (!ASCIIUtility.AllBytesInUInt32AreAscii(((uint*)pInputBuffer)[0] | ((uint*)pInputBuffer)[1]))
{
goto LoopTerminatedEarlyDueToNonAsciiDataInFirstPair;
}

if (!ASCIIUtility.AllBytesInUInt32AreAscii(((uint*)pInputBuffer)[2] | ((uint*)pInputBuffer)[3]))
{
goto LoopTerminatedEarlyDueToNonAsciiDataInSecondPair;
if (!ASCIIUtility.AllBytesInUInt32AreAscii(((uint*)pInputBuffer)[2] | ((uint*)pInputBuffer)[3]))
{
goto LoopTerminatedEarlyDueToNonAsciiDataInSecondPair;
}
}
}

pInputBuffer += 4 * sizeof(uint); // consumed 4 DWORDs
} while (pInputBuffer <= pInputBufferFinalPosAtWhichCanSafelyLoop);
pInputBuffer += 4 * sizeof(uint); // consumed 4 DWORDs
} while (pInputBuffer <= pInputBufferFinalPosAtWhichCanSafelyLoop);
}

continue; // need to perform a bounds check because we might be running out of data

Expand Down