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[NO MERGE] BitOps analysis CoreFX (WIP) #34917

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[NO MERGE] BitOps analysis CoreFX (WIP) #34917

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6a96d26
Update call sites for https://github.com/dotnet/corert/pull/6911
Jan 29, 2019
6485bf1
Another callsite
Jan 29, 2019
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2 changes: 1 addition & 1 deletion src/Common/src/System/Net/WebSockets/ManagedWebSocket.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1262,7 +1262,7 @@ private static unsafe int ApplyMask(Span<byte> toMask, int mask, int maskIndex)
Debug.Assert(maskIndex < sizeof(int));

int maskShift = maskIndex * 8;
int shiftedMask = (int)(((uint)mask >> maskShift) | ((uint)mask << (32 - maskShift)));
int shiftedMask = BitOps.RotateRight(mask, maskShift);

// Try to use SIMD. We can if the number of bytes we're trying to mask is at least as much
// as the width of a vector and if the width is an even multiple of the mask.
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4 changes: 2 additions & 2 deletions ...rectoryServices.AccountManagement/src/System/DirectoryServices/AccountManagement/Utils.cs
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Expand Up @@ -45,12 +45,12 @@ internal static bool AreBytesEqual(byte[] src, byte[] tgt)

internal static void ClearBit(ref int value, uint bitmask)
{
value = (int)(((uint)value) & ((uint)(~bitmask)));
BitOps.ClearBit(ref value, (int)bitmask);
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Motivation to use uint for declared offset param

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I need to do some more analysis of the original code to make sure that the refactor is functionally equivalent.

}

internal static void SetBit(ref int value, uint bitmask)
{
value = (int)(((uint)value) | ((uint)bitmask));
BitOps.InsertBit(ref value, (uint)bitmask);
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I need to do some more analysis of the original code to make sure that the refactor is functionally equivalent.

}

// {0xa2, 0x3f,...} --> "a23f..."
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17 changes: 3 additions & 14 deletions src/System.Reflection.Metadata/src/System/Reflection/Internal/Utilities/BitArithmetic.cs
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Expand Up @@ -10,28 +10,17 @@ internal static class BitArithmetic
{
internal static int CountBits(int v)
{
return CountBits(unchecked((uint)v));
return BitOps.PopCount(v);
}

internal static int CountBits(uint v)
{
unchecked
{
v = v - ((v >> 1) & 0x55555555u);
v = (v & 0x33333333u) + ((v >> 2) & 0x33333333u);
return (int)((v + (v >> 4) & 0xF0F0F0Fu) * 0x1010101u) >> 24;
}
return BitOps.PopCount(v);
}

internal static int CountBits(ulong v)
{
const ulong Mask01010101 = 0x5555555555555555UL;
const ulong Mask00110011 = 0x3333333333333333UL;
const ulong Mask00001111 = 0x0F0F0F0F0F0F0F0FUL;
const ulong Mask00000001 = 0x0101010101010101UL;
v = v - ((v >> 1) & Mask01010101);
v = (v & Mask00110011) + ((v >> 2) & Mask00110011);
return (int)(unchecked(((v + (v >> 4)) & Mask00001111) * Mask00000001) >> 56);
return BitOps.PopCount(v);
}

internal static uint Align(uint position, uint alignment)
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