Add a missing = in BigInteger.cs

src/libraries/System.Runtime.Numerics/src/System/Numerics/BigInteger.cs

@@ -544,7 +544,7 @@ private BigInteger(Span<uint> value)
                 isNegative = true;
                 length = value.LastIndexOfAnyExcept(uint.MaxValue) + 1;
 
-                if ((length == 0) || ((int)value[length - 1] > 0))
+                if ((length == 0) || ((int)value[length - 1] >= 0))
                 {
                     // We ne need to preserve the sign bit
                     length++;

src/libraries/System.Runtime.Numerics/tests/BigInteger/MyBigInt.cs

@@ -877,6 +877,11 @@ public static List<byte> GetBytes(BitArray ba)
         }
 
         public static string Print(byte[] bytes)
+        {
+            return Print(bytes.AsSpan());
+        }
+
+        public static string Print(ReadOnlySpan<byte> bytes)
         {
             string ret = "make ";
 

src/libraries/System.Runtime.Numerics/tests/BigInteger/SampleGeneration.cs

@@ -0,0 +1,82 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace System.Numerics.Tests
+{
+    public static partial class SampleGeneration
+    {
+
+        public static IEnumerable<ReadOnlyMemory<T>> EnumerateSequence<T>(IEnumerable<T> elementSource, int minLength, int maxLengthExclusive)
+        {
+            return EnumerateSequence(elementSource.ToArray(), minLength, maxLengthExclusive);
+        }
+
+        public static IEnumerable<ReadOnlyMemory<T>> EnumerateSequence<T>(T[] elementSource, int minLength, int maxLengthExclusive)
+        {
+            for (var i = minLength; maxLengthExclusive > i; ++i)
+            {
+                foreach (var item in EnumerateSequence(elementSource, i))
+                {
+                    yield return item;
+                }
+            }
+        }
+
+        public static IEnumerable<ReadOnlyMemory<T>> EnumerateSequence<T>(IEnumerable<T> elementSource, int length)
+        {
+            return EnumerateSequence(elementSource.ToArray(), length);
+        }
+
+        public static IEnumerable<ReadOnlyMemory<T>> EnumerateSequence<T>(T[] elementSource, int length)
+        {
+            var a = new T[length];
+            var r = new ReadOnlyMemory<T>(a);
+            foreach (var _ in EnumerateSequenceYieldsCurrentCount(elementSource, a))
+            {
+                yield return r;
+            }
+        }
+
+        private static IEnumerable<long> EnumerateSequenceYieldsCurrentCount<T>(T[] elementSource, T[] buffer)
+        {
+            var c = 0L;
+            var b = elementSource.Length;
+            if (b != 0)
+            {
+                var stack = new int[buffer.Length];
+                for (var i = 0; i < buffer.Length; ++i)
+                {
+                    buffer[i] = elementSource[0];
+                }
+                {
+                L:;
+                    yield return c++;
+                    for (var i = 0; stack.Length != i; ++i)
+                    {
+                        var en = ++stack[i];
+                        if (b == en)
+                        {
+                        }
+                        else
+                        {
+                            buffer[i] = elementSource[en];
+                            for (; 0 <= --i;)
+                            {
+                                buffer[i] = elementSource[0];
+                                stack[i] = 0;
+                            }
+                            goto L;
+                        }
+                    }
+                }
+            }
+        }
+    }
+}

src/libraries/System.Runtime.Numerics/tests/BigInteger/UInt32Samples.cs

@@ -0,0 +1,138 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using Xunit;
+
+namespace System.Numerics.Tests
+{
+
+    public static partial class UInt32Samples
+    {
+        private static readonly uint[] set1 = new uint[] {
+            0B00000000000000000000000000000000U,
+            0B00000000000000000000000000000001U,
+            0B00111111111111111111111111111110U,
+            0B00111111111111111111111111111111U,
+
+            0B01000000000000000000000000000000U,
+            0B01000000000000000000000000000001U,
+            0B01111111111111111111111111111110U,
+            0B01111111111111111111111111111111U,
+
+            0B10000000000000000000000000000000U,
+            0B10000000000000000000000000000001U,
+            0B10111111111111111111111111111110U,
+            0B10111111111111111111111111111111U,
+
+            0B11000000000000000000000000000000U,
+            0B11000000000000000000000000000001U,
+            0B11111111111111111111111111111110U,
+            0B11111111111111111111111111111111U,
+        };
+
+        private static IEnumerable<uint> GetSet1()
+        {
+            foreach (var item in set1)
+            {
+                yield return item;
+            }
+        }
+
+        public static readonly IEnumerable<uint> Set1 = GetSet1();
+
+        private static readonly uint[] set2 = new uint[] {
+            0B00000000000000000000000000000000U,
+            0B00000000000000000000000000000001U,
+            0B00000000000000000100000000000000U,
+            0B00000000000000000100000000000001U,
+
+            0B00000000000000010000000000000000U,
+            0B00000000000000010000000000000001U,
+            0B00000000000000010100000000000000U,
+            0B00000000000000010100000000000001U,
+
+            0B00111111111111111111111111111110U,
+            0B00111111111111111111111111111111U,
+            0B00111111111111111011111111111110U,
+            0B00111111111111111011111111111111U,
+
+            0B00111111111111101111111111111110U,
+            0B00111111111111101111111111111111U,
+            0B00111111111111101011111111111110U,
+            0B00111111111111101011111111111111U,
+
+            0B01000000000000000000000000000000U,
+            0B01000000000000000000000000000001U,
+            0B01000000000000000100000000000000U,
+            0B01000000000000000100000000000001U,
+
+            0B01000000000000010000000000000000U,
+            0B01000000000000010000000000000001U,
+            0B01000000000000010100000000000000U,
+            0B01000000000000010100000000000001U,
+
+            0B01111111111111111111111111111110U,
+            0B01111111111111111111111111111111U,
+            0B01111111111111111011111111111110U,
+            0B01111111111111111011111111111111U,
+
+            0B01111111111111101111111111111110U,
+            0B01111111111111101111111111111111U,
+            0B01111111111111101011111111111110U,
+            0B01111111111111101011111111111111U,
+
+            0B10000000000000000000000000000000U,
+            0B10000000000000000000000000000001U,
+            0B10000000000000000100000000000000U,
+            0B10000000000000000100000000000001U,
+
+            0B10000000000000010000000000000000U,
+            0B10000000000000010000000000000001U,
+            0B10000000000000010100000000000000U,
+            0B10000000000000010100000000000001U,
+
+            0B10111111111111111111111111111110U,
+            0B10111111111111111111111111111111U,
+            0B10111111111111111011111111111110U,
+            0B10111111111111111011111111111111U,
+
+            0B10111111111111101111111111111110U,
+            0B10111111111111101111111111111111U,
+            0B10111111111111101011111111111110U,
+            0B10111111111111101011111111111111U,
+
+            0B11000000000000000000000000000000U,
+            0B11000000000000000000000000000001U,
+            0B11000000000000000100000000000000U,
+            0B11000000000000000100000000000001U,
+
+            0B11000000000000010000000000000000U,
+            0B11000000000000010000000000000001U,
+            0B11000000000000010100000000000000U,
+            0B11000000000000010100000000000001U,
+
+            0B11111111111111111111111111111110U,
+            0B11111111111111111111111111111111U,
+            0B11111111111111111011111111111110U,
+            0B11111111111111111011111111111111U,
+
+            0B11111111111111101111111111111110U,
+            0B11111111111111101111111111111111U,
+            0B11111111111111101011111111111110U,
+            0B11111111111111101011111111111111U,
+        };
+
+        private static IEnumerable<uint> GetSet2()
+        {
+            foreach (var item in set2)
+            {
+                yield return item;
+            }
+        }
+
+        public static readonly IEnumerable<uint> Set2 = GetSet2();
+    }
+}

src/libraries/System.Runtime.Numerics/tests/BigInteger/op_and.cs

@@ -1,6 +1,9 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.InteropServices;
 using Xunit;
 
 namespace System.Numerics.Tests
@@ -117,6 +120,26 @@ public static void RunAndTests()
             }
         }
 
+        [Fact]
+        public static void RunAndTestsForSampleSet1()
+        {
+            var s = SampleGeneration.EnumerateSequence(UInt32Samples.Set1, 2);
+            var t = SampleGeneration.EnumerateSequence(UInt32Samples.Set1, 2);
+
+            foreach (var i in s)
+            {
+                foreach (var j in t)
+                {
+                    var a = MemoryMarshal.AsBytes(i.Span);
+                    var b = MemoryMarshal.AsBytes(j.Span);
+
+                    VerifyAndString(Print(a) + Print(b) + "b&");
+
+                    VerifyAndString(Print(b) + Print(a) + "b&");
+                }
+            }
+        }
+
         private static void VerifyAndString(string opstring)
         {
             StackCalc sc = new StackCalc(opstring);
@@ -139,5 +162,10 @@ private static string Print(byte[] bytes)
         {
             return MyBigIntImp.Print(bytes);
         }
+
+        private static string Print(ReadOnlySpan<byte> bytes)
+        {
+            return MyBigIntImp.Print(bytes);
+        }
     }
 }

src/libraries/System.Runtime.Numerics/tests/System.Runtime.Numerics.Tests.csproj

@@ -48,10 +48,12 @@
     <Compile Include="BigInteger\pow.cs" />
     <Compile Include="BigInteger\properties.cs" />
     <Compile Include="BigInteger\remainder.cs" />
+    <Compile Include="BigInteger\SampleGeneration.cs" />
     <Compile Include="BigInteger\sign.cs" />
     <Compile Include="BigInteger\stackcalculator.cs" />
     <Compile Include="BigInteger\ToByteArray.cs" />
     <Compile Include="BigInteger\TryWriteBytes.cs" />
+    <Compile Include="BigInteger\UInt32Samples.cs" />
     <Compile Include="ComplexTests.cs" />
   </ItemGroup>
   <ItemGroup>