diff --git a/src/libraries/System.Memory/ref/System.Memory.cs b/src/libraries/System.Memory/ref/System.Memory.cs
index 9f998a0afe9ef..32e28be4e9d2f 100644
--- a/src/libraries/System.Memory/ref/System.Memory.cs
+++ b/src/libraries/System.Memory/ref/System.Memory.cs
@@ -438,6 +438,10 @@ public static partial class BinaryPrimitives
         public static int ReadInt32LittleEndian(System.ReadOnlySpan<byte> source) { throw null; }
         public static long ReadInt64BigEndian(System.ReadOnlySpan<byte> source) { throw null; }
         public static long ReadInt64LittleEndian(System.ReadOnlySpan<byte> source) { throw null; }
+        public static System.Int128 ReadInt128BigEndian(System.ReadOnlySpan<byte> source) { throw null; }
+        public static System.Int128 ReadInt128LittleEndian(System.ReadOnlySpan<byte> source) { throw null; }
+        public static nint ReadIntPtrBigEndian(System.ReadOnlySpan<byte> source) { throw null; }
+        public static nint ReadIntPtrLittleEndian(System.ReadOnlySpan<byte> source) { throw null; }
         public static float ReadSingleBigEndian(System.ReadOnlySpan<byte> source) { throw null; }
         public static float ReadSingleLittleEndian(System.ReadOnlySpan<byte> source) { throw null; }
         [System.CLSCompliantAttribute(false)]
@@ -452,6 +456,14 @@ public static partial class BinaryPrimitives
         public static ulong ReadUInt64BigEndian(System.ReadOnlySpan<byte> source) { throw null; }
         [System.CLSCompliantAttribute(false)]
         public static ulong ReadUInt64LittleEndian(System.ReadOnlySpan<byte> source) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static System.UInt128 ReadUInt128BigEndian(System.ReadOnlySpan<byte> source) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static System.UInt128 ReadUInt128LittleEndian(System.ReadOnlySpan<byte> source) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static nuint ReadUIntPtrBigEndian(System.ReadOnlySpan<byte> source) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static nuint ReadUIntPtrLittleEndian(System.ReadOnlySpan<byte> source) { throw null; }
         public static byte ReverseEndianness(byte value) { throw null; }
         public static short ReverseEndianness(short value) { throw null; }
         public static int ReverseEndianness(int value) { throw null; }
@@ -495,6 +507,10 @@ public static void ReverseEndianness(System.ReadOnlySpan<ushort> source, System.
         public static bool TryReadInt32LittleEndian(System.ReadOnlySpan<byte> source, out int value) { throw null; }
         public static bool TryReadInt64BigEndian(System.ReadOnlySpan<byte> source, out long value) { throw null; }
         public static bool TryReadInt64LittleEndian(System.ReadOnlySpan<byte> source, out long value) { throw null; }
+        public static bool TryReadInt128BigEndian(System.ReadOnlySpan<byte> source, out System.Int128 value) { throw null; }
+        public static bool TryReadInt128LittleEndian(System.ReadOnlySpan<byte> source, out System.Int128 value) { throw null; }
+        public static bool TryReadIntPtrBigEndian(System.ReadOnlySpan<byte> source, out nint value) { throw null; }
+        public static bool TryReadIntPtrLittleEndian(System.ReadOnlySpan<byte> source, out nint value) { throw null; }
         public static bool TryReadSingleBigEndian(System.ReadOnlySpan<byte> source, out float value) { throw null; }
         public static bool TryReadSingleLittleEndian(System.ReadOnlySpan<byte> source, out float value) { throw null; }
         [System.CLSCompliantAttribute(false)]
@@ -509,6 +525,14 @@ public static void ReverseEndianness(System.ReadOnlySpan<ushort> source, System.
         public static bool TryReadUInt64BigEndian(System.ReadOnlySpan<byte> source, out ulong value) { throw null; }
         [System.CLSCompliantAttribute(false)]
         public static bool TryReadUInt64LittleEndian(System.ReadOnlySpan<byte> source, out ulong value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static bool TryReadUInt128BigEndian(System.ReadOnlySpan<byte> source, out System.UInt128 value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static bool TryReadUInt128LittleEndian(System.ReadOnlySpan<byte> source, out System.UInt128 value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static bool TryReadUIntPtrBigEndian(System.ReadOnlySpan<byte> source, out nuint value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static bool TryReadUIntPtrLittleEndian(System.ReadOnlySpan<byte> source, out nuint value) { throw null; }
         public static bool TryWriteDoubleBigEndian(System.Span<byte> destination, double value) { throw null; }
         public static bool TryWriteDoubleLittleEndian(System.Span<byte> destination, double value) { throw null; }
         public static bool TryWriteHalfBigEndian(System.Span<byte> destination, System.Half value) { throw null; }
@@ -519,6 +543,10 @@ public static void ReverseEndianness(System.ReadOnlySpan<ushort> source, System.
         public static bool TryWriteInt32LittleEndian(System.Span<byte> destination, int value) { throw null; }
         public static bool TryWriteInt64BigEndian(System.Span<byte> destination, long value) { throw null; }
         public static bool TryWriteInt64LittleEndian(System.Span<byte> destination, long value) { throw null; }
+        public static bool TryWriteInt128BigEndian(System.Span<byte> destination, System.Int128 value) { throw null; }
+        public static bool TryWriteInt128LittleEndian(System.Span<byte> destination, System.Int128 value) { throw null; }
+        public static bool TryWriteIntPtrBigEndian(System.Span<byte> destination, nint value) { throw null; }
+        public static bool TryWriteIntPtrLittleEndian(System.Span<byte> destination, nint value) { throw null; }
         public static bool TryWriteSingleBigEndian(System.Span<byte> destination, float value) { throw null; }
         public static bool TryWriteSingleLittleEndian(System.Span<byte> destination, float value) { throw null; }
         [System.CLSCompliantAttribute(false)]
@@ -533,6 +561,14 @@ public static void ReverseEndianness(System.ReadOnlySpan<ushort> source, System.
         public static bool TryWriteUInt64BigEndian(System.Span<byte> destination, ulong value) { throw null; }
         [System.CLSCompliantAttribute(false)]
         public static bool TryWriteUInt64LittleEndian(System.Span<byte> destination, ulong value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static bool TryWriteUInt128BigEndian(System.Span<byte> destination, System.UInt128 value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static bool TryWriteUInt128LittleEndian(System.Span<byte> destination, System.UInt128 value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static bool TryWriteUIntPtrBigEndian(System.Span<byte> destination, nuint value) { throw null; }
+        [System.CLSCompliantAttribute(false)]
+        public static bool TryWriteUIntPtrLittleEndian(System.Span<byte> destination, nuint value) { throw null; }
         public static void WriteDoubleBigEndian(System.Span<byte> destination, double value) { }
         public static void WriteDoubleLittleEndian(System.Span<byte> destination, double value) { }
         public static void WriteHalfBigEndian(System.Span<byte> destination, System.Half value) { }
@@ -543,6 +579,10 @@ public static void WriteInt32BigEndian(System.Span<byte> destination, int value)
         public static void WriteInt32LittleEndian(System.Span<byte> destination, int value) { }
         public static void WriteInt64BigEndian(System.Span<byte> destination, long value) { }
         public static void WriteInt64LittleEndian(System.Span<byte> destination, long value) { }
+        public static void WriteInt128BigEndian(System.Span<byte> destination, System.Int128 value) { }
+        public static void WriteInt128LittleEndian(System.Span<byte> destination, System.Int128 value) { }
+        public static void WriteIntPtrBigEndian(System.Span<byte> destination, nint value) { }
+        public static void WriteIntPtrLittleEndian(System.Span<byte> destination, nint value) { }
         public static void WriteSingleBigEndian(System.Span<byte> destination, float value) { }
         public static void WriteSingleLittleEndian(System.Span<byte> destination, float value) { }
         [System.CLSCompliantAttribute(false)]
@@ -557,6 +597,14 @@ public static void WriteUInt32LittleEndian(System.Span<byte> destination, uint v
         public static void WriteUInt64BigEndian(System.Span<byte> destination, ulong value) { }
         [System.CLSCompliantAttribute(false)]
         public static void WriteUInt64LittleEndian(System.Span<byte> destination, ulong value) { }
+        [System.CLSCompliantAttribute(false)]
+        public static void WriteUInt128BigEndian(System.Span<byte> destination, System.UInt128 value) { }
+        [System.CLSCompliantAttribute(false)]
+        public static void WriteUInt128LittleEndian(System.Span<byte> destination, System.UInt128 value) { }
+        [System.CLSCompliantAttribute(false)]
+        public static void WriteUIntPtrBigEndian(System.Span<byte> destination, nuint value) { }
+        [System.CLSCompliantAttribute(false)]
+        public static void WriteUIntPtrLittleEndian(System.Span<byte> destination, nuint value) { }
     }
 }
 namespace System.Buffers.Text
diff --git a/src/libraries/System.Memory/tests/Binary/BinaryReaderUnitTests.cs b/src/libraries/System.Memory/tests/Binary/BinaryReaderUnitTests.cs
index b4fb102bb1e6d..8f3f01c7105d6 100644
--- a/src/libraries/System.Memory/tests/Binary/BinaryReaderUnitTests.cs
+++ b/src/libraries/System.Memory/tests/Binary/BinaryReaderUnitTests.cs
@@ -14,19 +14,21 @@ public class BinaryReaderUnitTests
         [Fact]
         public void SpanRead()
         {
-            ulong value; // [11 22 33 44 55 66 77 88]
+            UInt128 value; // [11 22 33 44 55 66 77 88, 99 AA BB CC DD EE FF 00]
+
             if (BitConverter.IsLittleEndian)
             {
-                value = 0x8877665544332211;
+                value = new UInt128(0x00FFEEDDCCBBAA99, 0x8877665544332211);
             }
             else
             {
-                value = 0x1122334455667788;
+                value = new UInt128(0x1122334455667788, 0x99AABBCCDDEEFF00);
             }
+
             Span<byte> span;
             unsafe
             {
-                span = new Span<byte>(&value, 8);
+                span = new Span<byte>(&value, sizeof(UInt128));
             }
 
             Assert.Equal<byte>(0x11, MemoryMarshal.Read<byte>(span));
@@ -85,6 +87,59 @@ public void SpanRead()
             Assert.True(TryReadInt64LittleEndian(span, out longValue));
             Assert.Equal<long>(unchecked((long)0x8877665544332211), longValue);
 
+            if (Environment.Is64BitProcess)
+            {
+                Assert.Equal<nuint>(unchecked((nuint)0x1122334455667788), ReadUIntPtrBigEndian(span));
+                Assert.True(TryReadUIntPtrBigEndian(span, out nuint nuintValue));
+                Assert.Equal<nuint>(unchecked((nuint)0x1122334455667788), nuintValue);
+
+                Assert.Equal<nuint>(unchecked((nuint)0x8877665544332211), ReadUIntPtrLittleEndian(span));
+                Assert.True(TryReadUIntPtrLittleEndian(span, out nuintValue));
+                Assert.Equal<nuint>(unchecked((nuint)0x8877665544332211), nuintValue);
+
+                Assert.Equal<nint>(unchecked((nint)0x1122334455667788), ReadIntPtrBigEndian(span));
+                Assert.True(TryReadIntPtrBigEndian(span, out nint nintValue));
+                Assert.Equal<nint>(unchecked((nint)0x1122334455667788), nintValue);
+
+                Assert.Equal<nint>(unchecked((nint)0x8877665544332211), ReadIntPtrLittleEndian(span));
+                Assert.True(TryReadIntPtrLittleEndian(span, out nintValue));
+                Assert.Equal<nint>(unchecked((nint)0x8877665544332211), nintValue);
+            }
+            else
+            {
+                Assert.Equal<nuint>(0x11223344, ReadUIntPtrBigEndian(span));
+                Assert.True(TryReadUIntPtrBigEndian(span, out nuint nuintValue));
+                Assert.Equal<nuint>(0x11223344, nuintValue);
+
+                Assert.Equal<nuint>(0x44332211, ReadUIntPtrLittleEndian(span));
+                Assert.True(TryReadUIntPtrLittleEndian(span, out nuintValue));
+                Assert.Equal<nuint>(0x44332211, nuintValue);
+
+                Assert.Equal<nint>(0x11223344, ReadIntPtrBigEndian(span));
+                Assert.True(TryReadIntPtrBigEndian(span, out nint nintValue));
+                Assert.Equal<nint>(0x11223344, nintValue);
+
+                Assert.Equal<nint>(0x44332211, ReadIntPtrLittleEndian(span));
+                Assert.True(TryReadIntPtrLittleEndian(span, out nintValue));
+                Assert.Equal<nint>(0x44332211, nintValue);
+            }
+
+            Assert.Equal<UInt128>(new UInt128(0x1122334455667788, 0x99AABBCCDDEEFF00), ReadUInt128BigEndian(span));
+            Assert.True(TryReadUInt128BigEndian(span, out UInt128 uint128Value));
+            Assert.Equal<UInt128>(new UInt128(0x1122334455667788, 0x99AABBCCDDEEFF00), uint128Value);
+
+            Assert.Equal<UInt128>(new UInt128(0x00FFEEDDCCBBAA99, 0x8877665544332211), ReadUInt128LittleEndian(span));
+            Assert.True(TryReadUInt128LittleEndian(span, out uint128Value));
+            Assert.Equal<UInt128>(new UInt128(0x00FFEEDDCCBBAA99, 0x8877665544332211), uint128Value);
+
+            Assert.Equal<Int128>(new Int128(0x1122334455667788, 0x99AABBCCDDEEFF00), ReadInt128BigEndian(span));
+            Assert.True(TryReadInt128BigEndian(span, out Int128 int128Value));
+            Assert.Equal<Int128>(new Int128(0x1122334455667788, 0x99AABBCCDDEEFF00), int128Value);
+
+            Assert.Equal<Int128>(new Int128(0x00FFEEDDCCBBAA99, 0x8877665544332211), ReadInt128LittleEndian(span));
+            Assert.True(TryReadInt128LittleEndian(span, out int128Value));
+            Assert.Equal<Int128>(new Int128(0x00FFEEDDCCBBAA99, 0x8877665544332211), int128Value);
+
             Half expectedHalf = BitConverter.Int16BitsToHalf(0x1122);
             Assert.Equal<Half>(expectedHalf, ReadHalfBigEndian(span));
             Assert.True(TryReadHalfBigEndian(span, out Half halfValue));
@@ -119,19 +174,21 @@ public void SpanRead()
         [Fact]
         public void ReadOnlySpanRead()
         {
-            ulong value; // [11 22 33 44 55 66 77 88]
+            UInt128 value; // [11 22 33 44 55 66 77 88, 99 AA BB CC DD EE FF 00]
+
             if (BitConverter.IsLittleEndian)
             {
-                value = 0x8877665544332211;
+                value = new UInt128(0x00FFEEDDCCBBAA99, 0x8877665544332211);
             }
             else
             {
-                value = 0x1122334455667788;
+                value = new UInt128(0x1122334455667788, 0x99AABBCCDDEEFF00);
             }
+
             ReadOnlySpan<byte> span;
             unsafe
             {
-                span = new ReadOnlySpan<byte>(&value, 8);
+                span = new ReadOnlySpan<byte>(&value, sizeof(UInt128));
             }
 
             Assert.Equal<byte>(0x11, MemoryMarshal.Read<byte>(span));
@@ -190,6 +247,59 @@ public void ReadOnlySpanRead()
             Assert.True(TryReadInt64LittleEndian(span, out longValue));
             Assert.Equal<long>(unchecked((long)0x8877665544332211), longValue);
 
+            if (Environment.Is64BitProcess)
+            {
+                Assert.Equal<nuint>(unchecked((nuint)0x1122334455667788), ReadUIntPtrBigEndian(span));
+                Assert.True(TryReadUIntPtrBigEndian(span, out nuint nuintValue));
+                Assert.Equal<nuint>(unchecked((nuint)(0x1122334455667788)), nuintValue);
+
+                Assert.Equal<nuint>(unchecked((nuint)0x8877665544332211), ReadUIntPtrLittleEndian(span));
+                Assert.True(TryReadUIntPtrLittleEndian(span, out nuintValue));
+                Assert.Equal<nuint>(unchecked((nuint)0x8877665544332211), nuintValue);
+
+                Assert.Equal<nint>(unchecked((nint)0x1122334455667788), ReadIntPtrBigEndian(span));
+                Assert.True(TryReadIntPtrBigEndian(span, out nint nintValue));
+                Assert.Equal<nint>(unchecked((nint)0x1122334455667788), nintValue);
+
+                Assert.Equal<nint>(unchecked((nint)0x8877665544332211), ReadIntPtrLittleEndian(span));
+                Assert.True(TryReadIntPtrLittleEndian(span, out nintValue));
+                Assert.Equal<nint>(unchecked((nint)0x8877665544332211), nintValue);
+            }
+            else
+            {
+                Assert.Equal<nuint>(0x11223344, ReadUIntPtrBigEndian(span));
+                Assert.True(TryReadUIntPtrBigEndian(span, out nuint nuintValue));
+                Assert.Equal<nuint>(0x11223344, nuintValue);
+
+                Assert.Equal<nuint>(0x44332211, ReadUIntPtrLittleEndian(span));
+                Assert.True(TryReadUIntPtrLittleEndian(span, out nuintValue));
+                Assert.Equal<nuint>(0x44332211, nuintValue);
+
+                Assert.Equal<nint>(0x11223344, ReadIntPtrBigEndian(span));
+                Assert.True(TryReadIntPtrBigEndian(span, out nint nintValue));
+                Assert.Equal<nint>(0x11223344, nintValue);
+
+                Assert.Equal<nint>(0x44332211, ReadIntPtrLittleEndian(span));
+                Assert.True(TryReadIntPtrLittleEndian(span, out nintValue));
+                Assert.Equal<nint>(0x44332211, nintValue);
+            }
+
+            Assert.Equal<UInt128>(new UInt128(0x1122334455667788, 0x99AABBCCDDEEFF00), ReadUInt128BigEndian(span));
+            Assert.True(TryReadUInt128BigEndian(span, out UInt128 uint128Value));
+            Assert.Equal<UInt128>(new UInt128(0x1122334455667788, 0x99AABBCCDDEEFF00), uint128Value);
+
+            Assert.Equal<UInt128>(new UInt128(0x00FFEEDDCCBBAA99, 0x8877665544332211), ReadUInt128LittleEndian(span));
+            Assert.True(TryReadUInt128LittleEndian(span, out uint128Value));
+            Assert.Equal<UInt128>(new UInt128(0x00FFEEDDCCBBAA99, 0x8877665544332211), uint128Value);
+
+            Assert.Equal<Int128>(new Int128(0x1122334455667788, 0x99AABBCCDDEEFF00), ReadInt128BigEndian(span));
+            Assert.True(TryReadInt128BigEndian(span, out Int128 int128Value));
+            Assert.Equal<Int128>(new Int128(0x1122334455667788, 0x99AABBCCDDEEFF00), int128Value);
+
+            Assert.Equal<Int128>(new Int128(0x00FFEEDDCCBBAA99, 0x8877665544332211), ReadInt128LittleEndian(span));
+            Assert.True(TryReadInt128LittleEndian(span, out int128Value));
+            Assert.Equal<Int128>(new Int128(0x00FFEEDDCCBBAA99, 0x8877665544332211), int128Value);
+
             Half expectedHalf = BitConverter.Int16BitsToHalf(0x1122);
             Assert.Equal<Half>(expectedHalf, ReadHalfBigEndian(span));
             Assert.True(TryReadHalfBigEndian(span, out Half halfValue));
@@ -236,6 +346,10 @@ public void SpanReadFail()
             Assert.False(MemoryMarshal.TryRead(span, out int intValue));
             TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<long>(_span));
             Assert.False(MemoryMarshal.TryRead(span, out long longValue));
+            TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<nint>(_span));
+            Assert.False(MemoryMarshal.TryRead(span, out nint nintValue));
+            TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<Int128>(_span));
+            Assert.False(MemoryMarshal.TryRead(span, out Int128 int128Value));
 
             TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<ushort>(_span));
             Assert.False(MemoryMarshal.TryRead(span, out ushort ushortValue));
@@ -243,6 +357,10 @@ public void SpanReadFail()
             Assert.False(MemoryMarshal.TryRead(span, out uint uintValue));
             TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<ulong>(_span));
             Assert.False(MemoryMarshal.TryRead(span, out ulong ulongValue));
+            TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<nuint>(_span));
+            Assert.False(MemoryMarshal.TryRead(span, out nuint nuintValue));
+            TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<UInt128>(_span));
+            Assert.False(MemoryMarshal.TryRead(span, out UInt128 uint128Value));
 
             TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<Half>(_span));
             Assert.False(MemoryMarshal.TryRead(span, out Half halfValue));
@@ -271,6 +389,10 @@ public void ReadOnlySpanReadFail()
             Assert.False(MemoryMarshal.TryRead(span, out int intValue));
             TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<long>(_span));
             Assert.False(MemoryMarshal.TryRead(span, out long longValue));
+            TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<nint>(_span));
+            Assert.False(MemoryMarshal.TryRead(span, out nint nintValue));
+            TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<Int128>(_span));
+            Assert.False(MemoryMarshal.TryRead(span, out Int128 int128Value));
 
             TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<ushort>(_span));
             Assert.False(MemoryMarshal.TryRead(span, out ushort ushortValue));
@@ -278,6 +400,10 @@ public void ReadOnlySpanReadFail()
             Assert.False(MemoryMarshal.TryRead(span, out uint uintValue));
             TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<ulong>(_span));
             Assert.False(MemoryMarshal.TryRead(span, out ulong ulongValue));
+            TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<nuint>(_span));
+            Assert.False(MemoryMarshal.TryRead(span, out nuint nuintValue));
+            TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<UInt128>(_span));
+            Assert.False(MemoryMarshal.TryRead(span, out UInt128 uint128Value));
 
             TestHelpers.AssertThrows<ArgumentOutOfRangeException, byte>(span, (_span) => MemoryMarshal.Read<Half>(_span));
             Assert.False(MemoryMarshal.TryRead(span, out Half halfValue));
@@ -314,6 +440,25 @@ public void SpanWriteAndReadBigEndianHeterogeneousStruct()
             WriteDoubleBigEndian(spanBE.Slice(72), s_testStruct.D1);
             WriteHalfBigEndian(spanBE.Slice(80), s_testStruct.H0);
             WriteHalfBigEndian(spanBE.Slice(82), s_testStruct.H1);
+            WriteInt128BigEndian(spanBE.Slice(84), s_testStruct.I128_0);
+            WriteInt128BigEndian(spanBE.Slice(100), s_testStruct.I128_1);
+            WriteUInt128BigEndian(spanBE.Slice(116), s_testStruct.U128_0);
+            WriteUInt128BigEndian(spanBE.Slice(132), s_testStruct.U128_1);
+
+            if (Environment.Is64BitProcess)
+            {
+                WriteIntPtrBigEndian(spanBE.Slice(148), s_testStruct.N0);
+                WriteIntPtrBigEndian(spanBE.Slice(156), s_testStruct.N1);
+                WriteUIntPtrBigEndian(spanBE.Slice(164), s_testStruct.UN0);
+                WriteUIntPtrBigEndian(spanBE.Slice(172), s_testStruct.UN1);
+            }
+            else
+            {
+                WriteIntPtrBigEndian(spanBE.Slice(148), s_testStruct.N0);
+                WriteIntPtrBigEndian(spanBE.Slice(152), s_testStruct.N1);
+                WriteUIntPtrBigEndian(spanBE.Slice(156), s_testStruct.UN0);
+                WriteUIntPtrBigEndian(spanBE.Slice(160), s_testStruct.UN1);
+            }
 
             ReadOnlySpan<byte> readOnlySpanBE = new ReadOnlySpan<byte>(spanBE.ToArray());
 
@@ -336,9 +481,28 @@ public void SpanWriteAndReadBigEndianHeterogeneousStruct()
                 F1 = ReadSingleBigEndian(spanBE.Slice(68)),
                 D1 = ReadDoubleBigEndian(spanBE.Slice(72)),
                 H0 = ReadHalfBigEndian(spanBE.Slice(80)),
-                H1 = ReadHalfBigEndian(spanBE.Slice(82))
+                H1 = ReadHalfBigEndian(spanBE.Slice(82)),
+                I128_0 = ReadInt128BigEndian(spanBE.Slice(84)),
+                I128_1 = ReadInt128BigEndian(spanBE.Slice(100)),
+                U128_0 = ReadUInt128BigEndian(spanBE.Slice(116)),
+                U128_1 = ReadUInt128BigEndian(spanBE.Slice(132)),
             };
 
+            if (Environment.Is64BitProcess)
+            {
+                readStruct.N0 = ReadIntPtrBigEndian(spanBE.Slice(148));
+                readStruct.N1 = ReadIntPtrBigEndian(spanBE.Slice(156));
+                readStruct.UN0 = ReadUIntPtrBigEndian(spanBE.Slice(164));
+                readStruct.UN1 = ReadUIntPtrBigEndian(spanBE.Slice(172));
+            }
+            else
+            {
+                readStruct.N0 = ReadIntPtrBigEndian(spanBE.Slice(148));
+                readStruct.N1 = ReadIntPtrBigEndian(spanBE.Slice(152));
+                readStruct.UN0 = ReadUIntPtrBigEndian(spanBE.Slice(156));
+                readStruct.UN1 = ReadUIntPtrBigEndian(spanBE.Slice(160));
+            }
+
             var readStructFromReadOnlySpan = new TestStruct
             {
                 S0 = ReadInt16BigEndian(readOnlySpanBE),
@@ -358,9 +522,28 @@ public void SpanWriteAndReadBigEndianHeterogeneousStruct()
                 F1 = ReadSingleBigEndian(readOnlySpanBE.Slice(68)),
                 D1 = ReadDoubleBigEndian(readOnlySpanBE.Slice(72)),
                 H0 = ReadHalfBigEndian(readOnlySpanBE.Slice(80)),
-                H1 = ReadHalfBigEndian(readOnlySpanBE.Slice(82))
+                H1 = ReadHalfBigEndian(readOnlySpanBE.Slice(82)),
+                I128_0 = ReadInt128BigEndian(readOnlySpanBE.Slice(84)),
+                I128_1 = ReadInt128BigEndian(readOnlySpanBE.Slice(100)),
+                U128_0 = ReadUInt128BigEndian(readOnlySpanBE.Slice(116)),
+                U128_1 = ReadUInt128BigEndian(readOnlySpanBE.Slice(132)),
             };
 
+            if (Environment.Is64BitProcess)
+            {
+                readStructFromReadOnlySpan.N0 = ReadIntPtrBigEndian(readOnlySpanBE.Slice(148));
+                readStructFromReadOnlySpan.N1 = ReadIntPtrBigEndian(readOnlySpanBE.Slice(156));
+                readStructFromReadOnlySpan.UN0 = ReadUIntPtrBigEndian(readOnlySpanBE.Slice(164));
+                readStructFromReadOnlySpan.UN1 = ReadUIntPtrBigEndian(readOnlySpanBE.Slice(172));
+            }
+            else
+            {
+                readStructFromReadOnlySpan.N0 = ReadIntPtrBigEndian(readOnlySpanBE.Slice(148));
+                readStructFromReadOnlySpan.N1 = ReadIntPtrBigEndian(readOnlySpanBE.Slice(152));
+                readStructFromReadOnlySpan.UN0 = ReadUIntPtrBigEndian(readOnlySpanBE.Slice(156));
+                readStructFromReadOnlySpan.UN1 = ReadUIntPtrBigEndian(readOnlySpanBE.Slice(160));
+            }
+
             Assert.Equal(s_testStruct, readStruct);
             Assert.Equal(s_testStruct, readStructFromReadOnlySpan);
         }
@@ -388,6 +571,25 @@ public void SpanWriteAndReadLittleEndianHeterogeneousStruct()
             WriteDoubleLittleEndian(spanLE.Slice(72), s_testStruct.D1);
             WriteHalfLittleEndian(spanLE.Slice(80), s_testStruct.H0);
             WriteHalfLittleEndian(spanLE.Slice(82), s_testStruct.H1);
+            WriteInt128LittleEndian(spanLE.Slice(84), s_testStruct.I128_0);
+            WriteInt128LittleEndian(spanLE.Slice(100), s_testStruct.I128_1);
+            WriteUInt128LittleEndian(spanLE.Slice(116), s_testStruct.U128_0);
+            WriteUInt128LittleEndian(spanLE.Slice(132), s_testStruct.U128_1);
+
+            if (Environment.Is64BitProcess)
+            {
+                WriteIntPtrLittleEndian(spanLE.Slice(148), s_testStruct.N0);
+                WriteIntPtrLittleEndian(spanLE.Slice(156), s_testStruct.N1);
+                WriteUIntPtrLittleEndian(spanLE.Slice(164), s_testStruct.UN0);
+                WriteUIntPtrLittleEndian(spanLE.Slice(172), s_testStruct.UN1);
+            }
+            else
+            {
+                WriteIntPtrLittleEndian(spanLE.Slice(148), s_testStruct.N0);
+                WriteIntPtrLittleEndian(spanLE.Slice(152), s_testStruct.N1);
+                WriteUIntPtrLittleEndian(spanLE.Slice(156), s_testStruct.UN0);
+                WriteUIntPtrLittleEndian(spanLE.Slice(160), s_testStruct.UN1);
+            }
 
             ReadOnlySpan<byte> readOnlySpanLE = new ReadOnlySpan<byte>(spanLE.ToArray());
 
@@ -410,9 +612,28 @@ public void SpanWriteAndReadLittleEndianHeterogeneousStruct()
                 F1 = ReadSingleLittleEndian(spanLE.Slice(68)),
                 D1 = ReadDoubleLittleEndian(spanLE.Slice(72)),
                 H0 = ReadHalfLittleEndian(spanLE.Slice(80)),
-                H1 = ReadHalfLittleEndian(spanLE.Slice(82))
+                H1 = ReadHalfLittleEndian(spanLE.Slice(82)),
+                I128_0 = ReadInt128LittleEndian(spanLE.Slice(84)),
+                I128_1 = ReadInt128LittleEndian(spanLE.Slice(100)),
+                U128_0 = ReadUInt128LittleEndian(spanLE.Slice(116)),
+                U128_1 = ReadUInt128LittleEndian(spanLE.Slice(132)),
             };
 
+            if (Environment.Is64BitProcess)
+            {
+                readStruct.N0 = ReadIntPtrLittleEndian(spanLE.Slice(148));
+                readStruct.N1 = ReadIntPtrLittleEndian(spanLE.Slice(156));
+                readStruct.UN0 = ReadUIntPtrLittleEndian(spanLE.Slice(164));
+                readStruct.UN1 = ReadUIntPtrLittleEndian(spanLE.Slice(172));
+            }
+            else
+            {
+                readStruct.N0 = ReadIntPtrLittleEndian(spanLE.Slice(148));
+                readStruct.N1 = ReadIntPtrLittleEndian(spanLE.Slice(152));
+                readStruct.UN0 = ReadUIntPtrLittleEndian(spanLE.Slice(156));
+                readStruct.UN1 = ReadUIntPtrLittleEndian(spanLE.Slice(160));
+            }
+
             var readStructFromReadOnlySpan = new TestStruct
             {
                 S0 = ReadInt16LittleEndian(readOnlySpanLE),
@@ -432,9 +653,28 @@ public void SpanWriteAndReadLittleEndianHeterogeneousStruct()
                 F1 = ReadSingleLittleEndian(readOnlySpanLE.Slice(68)),
                 D1 = ReadDoubleLittleEndian(readOnlySpanLE.Slice(72)),
                 H0 = ReadHalfLittleEndian(readOnlySpanLE.Slice(80)),
-                H1 = ReadHalfLittleEndian(readOnlySpanLE.Slice(82))
+                H1 = ReadHalfLittleEndian(readOnlySpanLE.Slice(82)),
+                I128_0 = ReadInt128LittleEndian(readOnlySpanLE.Slice(84)),
+                I128_1 = ReadInt128LittleEndian(readOnlySpanLE.Slice(100)),
+                U128_0 = ReadUInt128LittleEndian(readOnlySpanLE.Slice(116)),
+                U128_1 = ReadUInt128LittleEndian(readOnlySpanLE.Slice(132)),
             };
 
+            if (Environment.Is64BitProcess)
+            {
+                readStructFromReadOnlySpan.N0 = ReadIntPtrLittleEndian(readOnlySpanLE.Slice(148));
+                readStructFromReadOnlySpan.N1 = ReadIntPtrLittleEndian(readOnlySpanLE.Slice(156));
+                readStructFromReadOnlySpan.UN0 = ReadUIntPtrLittleEndian(readOnlySpanLE.Slice(164));
+                readStructFromReadOnlySpan.UN1 = ReadUIntPtrLittleEndian(readOnlySpanLE.Slice(172));
+            }
+            else
+            {
+                readStructFromReadOnlySpan.N0 = ReadIntPtrLittleEndian(readOnlySpanLE.Slice(148));
+                readStructFromReadOnlySpan.N1 = ReadIntPtrLittleEndian(readOnlySpanLE.Slice(152));
+                readStructFromReadOnlySpan.UN0 = ReadUIntPtrLittleEndian(readOnlySpanLE.Slice(156));
+                readStructFromReadOnlySpan.UN1 = ReadUIntPtrLittleEndian(readOnlySpanLE.Slice(160));
+            }
+
             Assert.Equal(s_testStruct, readStruct);
             Assert.Equal(s_testStruct, readStructFromReadOnlySpan);
         }
@@ -570,6 +810,14 @@ public void ReadingStructFieldByFieldOrReadAndReverseEndianness()
             D1 = double.MinValue,
             H0 = Half.MaxValue,
             H1 = Half.MinValue,
+            I128_0 = Int128.MaxValue,
+            I128_1 = Int128.MinValue,
+            U128_1 = UInt128.MinValue,
+            U128_0 = UIntPtr.MaxValue,
+            N0 = nint.MaxValue,
+            N1 = nint.MinValue,
+            UN1 = nuint.MinValue,
+            UN0 = nuint.MaxValue,
         };
 
         [StructLayout(LayoutKind.Sequential)]
@@ -593,6 +841,14 @@ private struct TestStruct
             public double D1;
             public Half H0;
             public Half H1;
+            public Int128 I128_0;
+            public Int128 I128_1;
+            public UInt128 U128_1;
+            public UInt128 U128_0;
+            public nint N0;
+            public nint N1;
+            public nuint UN1;
+            public nuint UN0;
         }
     }
 }
diff --git a/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.ReadBigEndian.cs b/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.ReadBigEndian.cs
index 93e40c52f7359..07e961d22b0c2 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.ReadBigEndian.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.ReadBigEndian.cs
@@ -43,7 +43,7 @@ public static Half ReadHalfBigEndian(ReadOnlySpan<byte> source)
         }
 
         /// <summary>
-        /// Reads an Int16 out of a read-only span of bytes as big endian.
+        /// Reads a <see cref="short" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static short ReadInt16BigEndian(ReadOnlySpan<byte> source)
@@ -54,7 +54,7 @@ public static short ReadInt16BigEndian(ReadOnlySpan<byte> source)
         }
 
         /// <summary>
-        /// Reads an Int32 out of a read-only span of bytes as big endian.
+        /// Reads a <see cref="int" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static int ReadInt32BigEndian(ReadOnlySpan<byte> source)
@@ -65,7 +65,7 @@ public static int ReadInt32BigEndian(ReadOnlySpan<byte> source)
         }
 
         /// <summary>
-        /// Reads an Int64 out of a read-only span of bytes as big endian.
+        /// Reads a <see cref="long" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static long ReadInt64BigEndian(ReadOnlySpan<byte> source)
@@ -75,6 +75,28 @@ public static long ReadInt64BigEndian(ReadOnlySpan<byte> source)
                 MemoryMarshal.Read<long>(source);
         }
 
+        /// <summary>
+        /// Reads a <see cref="Int128" /> from the beginning of a read-only span of bytes, as big endian.
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static Int128 ReadInt128BigEndian(ReadOnlySpan<byte> source)
+        {
+            return BitConverter.IsLittleEndian ?
+                ReverseEndianness(MemoryMarshal.Read<Int128>(source)) :
+                MemoryMarshal.Read<Int128>(source);
+        }
+
+        /// <summary>
+        /// Reads a <see cref="nint" /> from the beginning of a read-only span of bytes, as big endian.
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static nint ReadIntPtrBigEndian(ReadOnlySpan<byte> source)
+        {
+            return BitConverter.IsLittleEndian ?
+                ReverseEndianness(MemoryMarshal.Read<nint>(source)) :
+                MemoryMarshal.Read<nint>(source);
+        }
+
         /// <summary>
         /// Reads a <see cref="float" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
@@ -93,7 +115,7 @@ public static float ReadSingleBigEndian(ReadOnlySpan<byte> source)
         }
 
         /// <summary>
-        /// Reads a UInt16 out of a read-only span of bytes as big endian.
+        /// Reads a <see cref="ushort" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -105,7 +127,7 @@ public static ushort ReadUInt16BigEndian(ReadOnlySpan<byte> source)
         }
 
         /// <summary>
-        /// Reads a UInt32 out of a read-only span of bytes as big endian.
+        /// Reads a <see cref="uint" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -117,7 +139,7 @@ public static uint ReadUInt32BigEndian(ReadOnlySpan<byte> source)
         }
 
         /// <summary>
-        /// Reads a UInt64 out of a read-only span of bytes as big endian.
+        /// Reads a <see cref="ulong" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -128,6 +150,30 @@ public static ulong ReadUInt64BigEndian(ReadOnlySpan<byte> source)
                 MemoryMarshal.Read<ulong>(source);
         }
 
+        /// <summary>
+        /// Reads a <see cref="UInt128" /> from the beginning of a read-only span of bytes, as big endian.
+        /// </summary>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static UInt128 ReadUInt128BigEndian(ReadOnlySpan<byte> source)
+        {
+            return BitConverter.IsLittleEndian ?
+                ReverseEndianness(MemoryMarshal.Read<UInt128>(source)) :
+                MemoryMarshal.Read<UInt128>(source);
+        }
+
+        /// <summary>
+        /// Reads a <see cref="nuint" /> from the beginning of a read-only span of bytes, as big endian.
+        /// </summary>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static nuint ReadUIntPtrBigEndian(ReadOnlySpan<byte> source)
+        {
+            return BitConverter.IsLittleEndian ?
+                ReverseEndianness(MemoryMarshal.Read<nuint>(source)) :
+                MemoryMarshal.Read<nuint>(source);
+        }
+
         /// <summary>
         /// Reads a <see cref="double" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
@@ -173,9 +219,9 @@ public static bool TryReadHalfBigEndian(ReadOnlySpan<byte> source, out Half valu
         }
 
         /// <summary>
-        /// Reads an Int16 out of a read-only span of bytes as big endian.
+        /// Reads a <see cref="short" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
-        /// <returns>If the span is too small to contain an Int16, return false.</returns>
+        /// <returns>If the span is too small to contain a <see cref="short" />, return false.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool TryReadInt16BigEndian(ReadOnlySpan<byte> source, out short value)
         {
@@ -190,9 +236,9 @@ public static bool TryReadInt16BigEndian(ReadOnlySpan<byte> source, out short va
         }
 
         /// <summary>
-        /// Reads an Int32 out of a read-only span of bytes as big endian.
+        /// Reads a <see cref="int" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
-        /// <returns>If the span is too small to contain an Int32, return false.</returns>
+        /// <returns>If the span is too small to contain a <see cref="int" />, return false.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool TryReadInt32BigEndian(ReadOnlySpan<byte> source, out int value)
         {
@@ -207,9 +253,9 @@ public static bool TryReadInt32BigEndian(ReadOnlySpan<byte> source, out int valu
         }
 
         /// <summary>
-        /// Reads an Int64 out of a read-only span of bytes as big endian.
+        /// Reads a <see cref="long" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
-        /// <returns>If the span is too small to contain an Int64, return false.</returns>
+        /// <returns>If the span is too small to contain a <see cref="long" />, return false.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool TryReadInt64BigEndian(ReadOnlySpan<byte> source, out long value)
         {
@@ -223,6 +269,40 @@ public static bool TryReadInt64BigEndian(ReadOnlySpan<byte> source, out long val
             return MemoryMarshal.TryRead(source, out value);
         }
 
+        /// <summary>
+        /// Reads a <see cref="Int128" /> from the beginning of a read-only span of bytes, as big endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain a <see cref="Int128" />, return false.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryReadInt128BigEndian(ReadOnlySpan<byte> source, out Int128 value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                bool success = MemoryMarshal.TryRead(source, out Int128 tmp);
+                value = ReverseEndianness(tmp);
+                return success;
+            }
+
+            return MemoryMarshal.TryRead(source, out value);
+        }
+
+        /// <summary>
+        /// Reads a <see cref="nint" /> from the beginning of a read-only span of bytes, as big endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain a <see cref="nint" />, return false.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryReadIntPtrBigEndian(ReadOnlySpan<byte> source, out nint value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                bool success = MemoryMarshal.TryRead(source, out nint tmp);
+                value = ReverseEndianness(tmp);
+                return success;
+            }
+
+            return MemoryMarshal.TryRead(source, out value);
+        }
+
         /// <summary>
         /// Reads a <see cref="float" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
@@ -245,9 +325,9 @@ public static bool TryReadSingleBigEndian(ReadOnlySpan<byte> source, out float v
         }
 
         /// <summary>
-        /// Reads a UInt16 out of a read-only span of bytes as big endian.
+        /// Reads a <see cref="ushort" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
-        /// <returns>If the span is too small to contain a UInt16, return false.</returns>
+        /// <returns>If the span is too small to contain a <see cref="ushort" />, return false.</returns>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool TryReadUInt16BigEndian(ReadOnlySpan<byte> source, out ushort value)
@@ -263,9 +343,9 @@ public static bool TryReadUInt16BigEndian(ReadOnlySpan<byte> source, out ushort
         }
 
         /// <summary>
-        /// Reads a UInt32 out of a read-only span of bytes as big endian.
+        /// Reads a <see cref="uint" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
-        /// <returns>If the span is too small to contain a UInt32, return false.</returns>
+        /// <returns>If the span is too small to contain a <see cref="uint" />, return false.</returns>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool TryReadUInt32BigEndian(ReadOnlySpan<byte> source, out uint value)
@@ -281,9 +361,9 @@ public static bool TryReadUInt32BigEndian(ReadOnlySpan<byte> source, out uint va
         }
 
         /// <summary>
-        /// Reads a UInt64 out of a read-only span of bytes as big endian.
+        /// Reads a <see cref="ulong" /> from the beginning of a read-only span of bytes, as big endian.
         /// </summary>
-        /// <returns>If the span is too small to contain a UInt64, return false.</returns>
+        /// <returns>If the span is too small to contain a <see cref="ulong" />, return false.</returns>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool TryReadUInt64BigEndian(ReadOnlySpan<byte> source, out ulong value)
@@ -297,5 +377,41 @@ public static bool TryReadUInt64BigEndian(ReadOnlySpan<byte> source, out ulong v
 
             return MemoryMarshal.TryRead(source, out value);
         }
+
+        /// <summary>
+        /// Reads a <see cref="UInt128" /> from the beginning of a read-only span of bytes, as big endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain a <see cref="UInt128" />, return false.</returns>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryReadUInt128BigEndian(ReadOnlySpan<byte> source, out UInt128 value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                bool success = MemoryMarshal.TryRead(source, out UInt128 tmp);
+                value = ReverseEndianness(tmp);
+                return success;
+            }
+
+            return MemoryMarshal.TryRead(source, out value);
+        }
+
+        /// <summary>
+        /// Reads a <see cref="nuint" /> from the beginning of a read-only span of bytes, as big endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain a <see cref="nuint" />, return false.</returns>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryReadUIntPtrBigEndian(ReadOnlySpan<byte> source, out nuint value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                bool success = MemoryMarshal.TryRead(source, out nuint tmp);
+                value = ReverseEndianness(tmp);
+                return success;
+            }
+
+            return MemoryMarshal.TryRead(source, out value);
+        }
     }
 }
diff --git a/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.ReadLittleEndian.cs b/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.ReadLittleEndian.cs
index 2115eec5c381c..8c9df7eef8692 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.ReadLittleEndian.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.ReadLittleEndian.cs
@@ -43,7 +43,7 @@ public static Half ReadHalfLittleEndian(ReadOnlySpan<byte> source)
         }
 
         /// <summary>
-        /// Reads an Int16 out of a read-only span of bytes as little endian.
+        /// Reads a <see cref="short" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static short ReadInt16LittleEndian(ReadOnlySpan<byte> source)
@@ -54,7 +54,7 @@ public static short ReadInt16LittleEndian(ReadOnlySpan<byte> source)
         }
 
         /// <summary>
-        /// Reads an Int32 out of a read-only span of bytes as little endian.
+        /// Reads a <see cref="int" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static int ReadInt32LittleEndian(ReadOnlySpan<byte> source)
@@ -65,7 +65,7 @@ public static int ReadInt32LittleEndian(ReadOnlySpan<byte> source)
         }
 
         /// <summary>
-        /// Reads an Int64 out of a read-only span of bytes as little endian.
+        /// Reads a <see cref="long" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static long ReadInt64LittleEndian(ReadOnlySpan<byte> source)
@@ -75,6 +75,28 @@ public static long ReadInt64LittleEndian(ReadOnlySpan<byte> source)
                 MemoryMarshal.Read<long>(source);
         }
 
+        /// <summary>
+        /// Reads a <see cref="Int128" /> from the beginning of a read-only span of bytes, as little endian.
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static Int128 ReadInt128LittleEndian(ReadOnlySpan<byte> source)
+        {
+            return !BitConverter.IsLittleEndian ?
+                ReverseEndianness(MemoryMarshal.Read<Int128>(source)) :
+                MemoryMarshal.Read<Int128>(source);
+        }
+
+        /// <summary>
+        /// Reads a <see cref="nint" /> from the beginning of a read-only span of bytes, as little endian.
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static nint ReadIntPtrLittleEndian(ReadOnlySpan<byte> source)
+        {
+            return !BitConverter.IsLittleEndian ?
+                ReverseEndianness(MemoryMarshal.Read<nint>(source)) :
+                MemoryMarshal.Read<nint>(source);
+        }
+
         /// <summary>
         /// Reads a <see cref="float" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
@@ -93,7 +115,7 @@ public static float ReadSingleLittleEndian(ReadOnlySpan<byte> source)
         }
 
         /// <summary>
-        /// Reads a UInt16 out of a read-only span of bytes as little endian.
+        /// Reads a <see cref="ushort" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -105,7 +127,7 @@ public static ushort ReadUInt16LittleEndian(ReadOnlySpan<byte> source)
         }
 
         /// <summary>
-        /// Reads a UInt32 out of a read-only span of bytes as little endian.
+        /// Reads a <see cref="uint" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -117,7 +139,7 @@ public static uint ReadUInt32LittleEndian(ReadOnlySpan<byte> source)
         }
 
         /// <summary>
-        /// Reads a UInt64 out of a read-only span of bytes as little endian.
+        /// Reads a <see cref="ulong" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -128,6 +150,30 @@ public static ulong ReadUInt64LittleEndian(ReadOnlySpan<byte> source)
                 MemoryMarshal.Read<ulong>(source);
         }
 
+        /// <summary>
+        /// Reads a <see cref="UInt128" /> from the beginning of a read-only span of bytes, as little endian.
+        /// </summary>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static UInt128 ReadUInt128LittleEndian(ReadOnlySpan<byte> source)
+        {
+            return !BitConverter.IsLittleEndian ?
+                ReverseEndianness(MemoryMarshal.Read<UInt128>(source)) :
+                MemoryMarshal.Read<UInt128>(source);
+        }
+
+        /// <summary>
+        /// Reads a <see cref="nuint" /> from the beginning of a read-only span of bytes, as little endian.
+        /// </summary>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static nuint ReadUIntPtrLittleEndian(ReadOnlySpan<byte> source)
+        {
+            return !BitConverter.IsLittleEndian ?
+                ReverseEndianness(MemoryMarshal.Read<nuint>(source)) :
+                MemoryMarshal.Read<nuint>(source);
+        }
+
         /// <summary>
         /// Reads a <see cref="double" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
@@ -173,9 +219,9 @@ public static bool TryReadHalfLittleEndian(ReadOnlySpan<byte> source, out Half v
         }
 
         /// <summary>
-        /// Reads an Int16 out of a read-only span of bytes as little endian.
+        /// Reads a <see cref="short" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
-        /// <returns>If the span is too small to contain an Int16, return false.</returns>
+        /// <returns>If the span is too small to contain a <see cref="short" />, return false.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool TryReadInt16LittleEndian(ReadOnlySpan<byte> source, out short value)
         {
@@ -190,9 +236,9 @@ public static bool TryReadInt16LittleEndian(ReadOnlySpan<byte> source, out short
         }
 
         /// <summary>
-        /// Reads an Int32 out of a read-only span of bytes as little endian.
+        /// Reads a <see cref="int" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
-        /// <returns>If the span is too small to contain an Int32, return false.</returns>
+        /// <returns>If the span is too small to contain a <see cref="int" />, return false.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool TryReadInt32LittleEndian(ReadOnlySpan<byte> source, out int value)
         {
@@ -207,9 +253,9 @@ public static bool TryReadInt32LittleEndian(ReadOnlySpan<byte> source, out int v
         }
 
         /// <summary>
-        /// Reads an Int64 out of a read-only span of bytes as little endian.
+        /// Reads a <see cref="long" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
-        /// <returns>If the span is too small to contain an Int64, return false.</returns>
+        /// <returns>If the span is too small to contain a <see cref="long" />, return false.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool TryReadInt64LittleEndian(ReadOnlySpan<byte> source, out long value)
         {
@@ -223,6 +269,40 @@ public static bool TryReadInt64LittleEndian(ReadOnlySpan<byte> source, out long
             return success;
         }
 
+        /// <summary>
+        /// Reads a <see cref="Int128" /> from the beginning of a read-only span of bytes, as little endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain a <see cref="Int128" />, return false.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryReadInt128LittleEndian(ReadOnlySpan<byte> source, out Int128 value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                return MemoryMarshal.TryRead(source, out value);
+            }
+
+            bool success = MemoryMarshal.TryRead(source, out Int128 tmp);
+            value = ReverseEndianness(tmp);
+            return success;
+        }
+
+        /// <summary>
+        /// Reads a <see cref="nint" /> from the beginning of a read-only span of bytes, as little endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain a <see cref="nint" />, return false.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryReadIntPtrLittleEndian(ReadOnlySpan<byte> source, out nint value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                return MemoryMarshal.TryRead(source, out value);
+            }
+
+            bool success = MemoryMarshal.TryRead(source, out nint tmp);
+            value = ReverseEndianness(tmp);
+            return success;
+        }
+
         /// <summary>
         /// Reads a <see cref="float" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
@@ -245,9 +325,9 @@ public static bool TryReadSingleLittleEndian(ReadOnlySpan<byte> source, out floa
         }
 
         /// <summary>
-        /// Reads a UInt16 out of a read-only span of bytes as little endian.
+        /// Reads a <see cref="ushort" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
-        /// <returns>If the span is too small to contain a UInt16, return false.</returns>
+        /// <returns>If the span is too small to contain a <see cref="ushort" />, return false.</returns>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool TryReadUInt16LittleEndian(ReadOnlySpan<byte> source, out ushort value)
@@ -263,9 +343,9 @@ public static bool TryReadUInt16LittleEndian(ReadOnlySpan<byte> source, out usho
         }
 
         /// <summary>
-        /// Reads a UInt32 out of a read-only span of bytes as little endian.
+        /// Reads a <see cref="uint" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
-        /// <returns>If the span is too small to contain a UInt32, return false.</returns>
+        /// <returns>If the span is too small to contain a <see cref="uint" />, return false.</returns>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool TryReadUInt32LittleEndian(ReadOnlySpan<byte> source, out uint value)
@@ -281,9 +361,9 @@ public static bool TryReadUInt32LittleEndian(ReadOnlySpan<byte> source, out uint
         }
 
         /// <summary>
-        /// Reads a UInt64 out of a read-only span of bytes as little endian.
+        /// Reads a <see cref="ulong" /> from the beginning of a read-only span of bytes, as little endian.
         /// </summary>
-        /// <returns>If the span is too small to contain a UInt64, return false.</returns>
+        /// <returns>If the span is too small to contain a <see cref="ulong" />, return false.</returns>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static bool TryReadUInt64LittleEndian(ReadOnlySpan<byte> source, out ulong value)
@@ -297,5 +377,41 @@ public static bool TryReadUInt64LittleEndian(ReadOnlySpan<byte> source, out ulon
             value = ReverseEndianness(tmp);
             return success;
         }
+
+        /// <summary>
+        /// Reads a <see cref="UInt128" /> from the beginning of a read-only span of bytes, as little endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain a <see cref="UInt128" />, return false.</returns>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryReadUInt128LittleEndian(ReadOnlySpan<byte> source, out UInt128 value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                return MemoryMarshal.TryRead(source, out value);
+            }
+
+            bool success = MemoryMarshal.TryRead(source, out UInt128 tmp);
+            value = ReverseEndianness(tmp);
+            return success;
+        }
+
+        /// <summary>
+        /// Reads a <see cref="nuint" /> from the beginning of a read-only span of bytes, as little endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain a <see cref="nuint" />, return false.</returns>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryReadUIntPtrLittleEndian(ReadOnlySpan<byte> source, out nuint value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                return MemoryMarshal.TryRead(source, out value);
+            }
+
+            bool success = MemoryMarshal.TryRead(source, out nuint tmp);
+            value = ReverseEndianness(tmp);
+            return success;
+        }
     }
 }
diff --git a/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.WriteBigEndian.cs b/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.WriteBigEndian.cs
index 2c32bb0f685e3..a30ff594e04be 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.WriteBigEndian.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.WriteBigEndian.cs
@@ -55,7 +55,7 @@ public static void WriteHalfBigEndian(Span<byte> destination, Half value)
         }
 
         /// <summary>
-        /// Writes an Int16 into a span of bytes as big endian.
+        /// Writes a <see cref="short" /> into a span of bytes, as big endian.
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static void WriteInt16BigEndian(Span<byte> destination, short value)
@@ -72,7 +72,7 @@ public static void WriteInt16BigEndian(Span<byte> destination, short value)
         }
 
         /// <summary>
-        /// Writes an Int32 into a span of bytes as big endian.
+        /// Writes a <see cref="int" /> into a span of bytes, as big endian.
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static void WriteInt32BigEndian(Span<byte> destination, int value)
@@ -89,7 +89,7 @@ public static void WriteInt32BigEndian(Span<byte> destination, int value)
         }
 
         /// <summary>
-        /// Writes an Int64 into a span of bytes as big endian.
+        /// Writes a <see cref="long" /> into a span of bytes, as big endian.
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static void WriteInt64BigEndian(Span<byte> destination, long value)
@@ -105,6 +105,40 @@ public static void WriteInt64BigEndian(Span<byte> destination, long value)
             }
         }
 
+        /// <summary>
+        /// Writes a <see cref="Int128" /> into a span of bytes, as big endian.
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void WriteInt128BigEndian(Span<byte> destination, Int128 value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                Int128 tmp = ReverseEndianness(value);
+                MemoryMarshal.Write(destination, ref tmp);
+            }
+            else
+            {
+                MemoryMarshal.Write(destination, ref value);
+            }
+        }
+
+        /// <summary>
+        /// Writes a <see cref="nint" /> into a span of bytes, as big endian.
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void WriteIntPtrBigEndian(Span<byte> destination, nint value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                nint tmp = ReverseEndianness(value);
+                MemoryMarshal.Write(destination, ref tmp);
+            }
+            else
+            {
+                MemoryMarshal.Write(destination, ref value);
+            }
+        }
+
         /// <summary>
         /// Writes a <see cref="float" /> into a span of bytes, as big endian.
         /// </summary>
@@ -129,7 +163,7 @@ public static void WriteSingleBigEndian(Span<byte> destination, float value)
         }
 
         /// <summary>
-        /// Write a UInt16 into a span of bytes as big endian.
+        /// Write a <see cref="ushort" /> into a span of bytes, as big endian.
         /// </summary>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -147,7 +181,7 @@ public static void WriteUInt16BigEndian(Span<byte> destination, ushort value)
         }
 
         /// <summary>
-        /// Write a UInt32 into a span of bytes as big endian.
+        /// Write a <see cref="uint" /> into a span of bytes, as big endian.
         /// </summary>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -165,7 +199,7 @@ public static void WriteUInt32BigEndian(Span<byte> destination, uint value)
         }
 
         /// <summary>
-        /// Write a UInt64 into a span of bytes as big endian.
+        /// Write a <see cref="ulong" /> into a span of bytes, as big endian.
         /// </summary>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -182,6 +216,42 @@ public static void WriteUInt64BigEndian(Span<byte> destination, ulong value)
             }
         }
 
+        /// <summary>
+        /// Writes a <see cref="UInt128" /> into a span of bytes, as big endian.
+        /// </summary>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void WriteUInt128BigEndian(Span<byte> destination, UInt128 value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                UInt128 tmp = ReverseEndianness(value);
+                MemoryMarshal.Write(destination, ref tmp);
+            }
+            else
+            {
+                MemoryMarshal.Write(destination, ref value);
+            }
+        }
+
+        /// <summary>
+        /// Writes a <see cref="nuint" /> into a span of bytes, as big endian.
+        /// </summary>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void WriteUIntPtrBigEndian(Span<byte> destination, nuint value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                nuint tmp = ReverseEndianness(value);
+                MemoryMarshal.Write(destination, ref tmp);
+            }
+            else
+            {
+                MemoryMarshal.Write(destination, ref value);
+            }
+        }
+
         /// <summary>
         /// Writes a <see cref="double" /> into a span of bytes, as big endian.
         /// </summary>
@@ -225,7 +295,7 @@ public static bool TryWriteHalfBigEndian(Span<byte> destination, Half value)
         }
 
         /// <summary>
-        /// Writes an Int16 into a span of bytes as big endian.
+        /// Writes a <see cref="short" /> into a span of bytes, as big endian.
         /// </summary>
         /// <returns>If the span is too small to contain the value, return false.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -241,7 +311,7 @@ public static bool TryWriteInt16BigEndian(Span<byte> destination, short value)
         }
 
         /// <summary>
-        /// Writes an Int32 into a span of bytes as big endian.
+        /// Writes a <see cref="int" /> into a span of bytes, as big endian.
         /// </summary>
         /// <returns>If the span is too small to contain the value, return false.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -257,7 +327,7 @@ public static bool TryWriteInt32BigEndian(Span<byte> destination, int value)
         }
 
         /// <summary>
-        /// Writes an Int64 into a span of bytes as big endian.
+        /// Writes a <see cref="long" /> into a span of bytes, as big endian.
         /// </summary>
         /// <returns>If the span is too small to contain the value, return false.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -272,6 +342,38 @@ public static bool TryWriteInt64BigEndian(Span<byte> destination, long value)
             return MemoryMarshal.TryWrite(destination, ref value);
         }
 
+        /// <summary>
+        /// Writes a <see cref="Int128" /> into a span of bytes, as big endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain the value, return false.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryWriteInt128BigEndian(Span<byte> destination, Int128 value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                Int128 tmp = ReverseEndianness(value);
+                return MemoryMarshal.TryWrite(destination, ref tmp);
+            }
+
+            return MemoryMarshal.TryWrite(destination, ref value);
+        }
+
+        /// <summary>
+        /// Writes a <see cref="nint" /> into a span of bytes, as big endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain the value, return false.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryWriteIntPtrBigEndian(Span<byte> destination, nint value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                nint tmp = ReverseEndianness(value);
+                return MemoryMarshal.TryWrite(destination, ref tmp);
+            }
+
+            return MemoryMarshal.TryWrite(destination, ref value);
+        }
+
         /// <summary>
         /// Writes a <see cref="float" /> into a span of bytes, as big endian.
         /// </summary>
@@ -294,7 +396,7 @@ public static bool TryWriteSingleBigEndian(Span<byte> destination, float value)
         }
 
         /// <summary>
-        /// Write a UInt16 into a span of bytes as big endian.
+        /// Write a <see cref="ushort" /> into a span of bytes, as big endian.
         /// </summary>
         /// <returns>If the span is too small to contain the value, return false.</returns>
         [CLSCompliant(false)]
@@ -311,7 +413,7 @@ public static bool TryWriteUInt16BigEndian(Span<byte> destination, ushort value)
         }
 
         /// <summary>
-        /// Write a UInt32 into a span of bytes as big endian.
+        /// Write a <see cref="uint" /> into a span of bytes, as big endian.
         /// </summary>
         /// <returns>If the span is too small to contain the value, return false.</returns>
         [CLSCompliant(false)]
@@ -328,7 +430,7 @@ public static bool TryWriteUInt32BigEndian(Span<byte> destination, uint value)
         }
 
         /// <summary>
-        /// Write a UInt64 into a span of bytes as big endian.
+        /// Write a <see cref="ulong" /> into a span of bytes, as big endian.
         /// </summary>
         /// <returns>If the span is too small to contain the value, return false.</returns>
         [CLSCompliant(false)]
@@ -343,5 +445,39 @@ public static bool TryWriteUInt64BigEndian(Span<byte> destination, ulong value)
 
             return MemoryMarshal.TryWrite(destination, ref value);
         }
+
+        /// <summary>
+        /// Writes a <see cref="UInt128" /> into a span of bytes, as big endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain the value, return false.</returns>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryWriteUInt128BigEndian(Span<byte> destination, UInt128 value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                UInt128 tmp = ReverseEndianness(value);
+                return MemoryMarshal.TryWrite(destination, ref tmp);
+            }
+
+            return MemoryMarshal.TryWrite(destination, ref value);
+        }
+
+        /// <summary>
+        /// Writes a <see cref="nuint" /> into a span of bytes, as big endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain the value, return false.</returns>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryWriteUIntPtrBigEndian(Span<byte> destination, nuint value)
+        {
+            if (BitConverter.IsLittleEndian)
+            {
+                nuint tmp = ReverseEndianness(value);
+                return MemoryMarshal.TryWrite(destination, ref tmp);
+            }
+
+            return MemoryMarshal.TryWrite(destination, ref value);
+        }
     }
 }
diff --git a/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.WriteLittleEndian.cs b/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.WriteLittleEndian.cs
index f88383490b513..efba216e68b43 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.WriteLittleEndian.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Buffers/Binary/BinaryPrimitives.WriteLittleEndian.cs
@@ -55,7 +55,7 @@ public static void WriteHalfLittleEndian(Span<byte> destination, Half value)
         }
 
         /// <summary>
-        /// Writes an Int16 into a span of bytes as little endian.
+        /// Writes a <see cref="short" /> into a span of bytes, as little endian.
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static void WriteInt16LittleEndian(Span<byte> destination, short value)
@@ -72,7 +72,7 @@ public static void WriteInt16LittleEndian(Span<byte> destination, short value)
         }
 
         /// <summary>
-        /// Writes an Int32 into a span of bytes as little endian.
+        /// Writes a <see cref="int" /> into a span of bytes, as little endian.
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static void WriteInt32LittleEndian(Span<byte> destination, int value)
@@ -89,7 +89,7 @@ public static void WriteInt32LittleEndian(Span<byte> destination, int value)
         }
 
         /// <summary>
-        /// Writes an Int64 into a span of bytes as little endian.
+        /// Writes a <see cref="long" /> into a span of bytes, as little endian.
         /// </summary>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public static void WriteInt64LittleEndian(Span<byte> destination, long value)
@@ -105,6 +105,40 @@ public static void WriteInt64LittleEndian(Span<byte> destination, long value)
             }
         }
 
+        /// <summary>
+        /// Writes a <see cref="Int128" /> into a span of bytes, as little endian.
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void WriteInt128LittleEndian(Span<byte> destination, Int128 value)
+        {
+            if (!BitConverter.IsLittleEndian)
+            {
+                Int128 tmp = ReverseEndianness(value);
+                MemoryMarshal.Write(destination, ref tmp);
+            }
+            else
+            {
+                MemoryMarshal.Write(destination, ref value);
+            }
+        }
+
+        /// <summary>
+        /// Writes a <see cref="nint" /> into a span of bytes, as little endian.
+        /// </summary>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void WriteIntPtrLittleEndian(Span<byte> destination, nint value)
+        {
+            if (!BitConverter.IsLittleEndian)
+            {
+                nint tmp = ReverseEndianness(value);
+                MemoryMarshal.Write(destination, ref tmp);
+            }
+            else
+            {
+                MemoryMarshal.Write(destination, ref value);
+            }
+        }
+
         /// <summary>
         /// Writes a <see cref="float" /> into a span of bytes, as little endian.
         /// </summary>
@@ -129,7 +163,7 @@ public static void WriteSingleLittleEndian(Span<byte> destination, float value)
         }
 
         /// <summary>
-        /// Write a UInt16 into a span of bytes as little endian.
+        /// Write a <see cref="ushort" /> into a span of bytes, as little endian.
         /// </summary>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -147,7 +181,7 @@ public static void WriteUInt16LittleEndian(Span<byte> destination, ushort value)
         }
 
         /// <summary>
-        /// Write a UInt32 into a span of bytes as little endian.
+        /// Write a <see cref="uint" /> into a span of bytes, as little endian.
         /// </summary>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -165,7 +199,7 @@ public static void WriteUInt32LittleEndian(Span<byte> destination, uint value)
         }
 
         /// <summary>
-        /// Write a UInt64 into a span of bytes as little endian.
+        /// Write a <see cref="ulong" /> into a span of bytes, as little endian.
         /// </summary>
         [CLSCompliant(false)]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -182,6 +216,42 @@ public static void WriteUInt64LittleEndian(Span<byte> destination, ulong value)
             }
         }
 
+        /// <summary>
+        /// Writes a <see cref="UInt128" /> into a span of bytes, as little endian.
+        /// </summary>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void WriteUInt128LittleEndian(Span<byte> destination, UInt128 value)
+        {
+            if (!BitConverter.IsLittleEndian)
+            {
+                UInt128 tmp = ReverseEndianness(value);
+                MemoryMarshal.Write(destination, ref tmp);
+            }
+            else
+            {
+                MemoryMarshal.Write(destination, ref value);
+            }
+        }
+
+        /// <summary>
+        /// Writes a <see cref="nuint" /> into a span of bytes, as little endian.
+        /// </summary>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void WriteUIntPtrLittleEndian(Span<byte> destination, nuint value)
+        {
+            if (!BitConverter.IsLittleEndian)
+            {
+                nuint tmp = ReverseEndianness(value);
+                MemoryMarshal.Write(destination, ref tmp);
+            }
+            else
+            {
+                MemoryMarshal.Write(destination, ref value);
+            }
+        }
+
         /// <summary>
         /// Writes a <see cref="double" /> into a span of bytes, as little endian.
         /// </summary>
@@ -225,7 +295,7 @@ public static bool TryWriteHalfLittleEndian(Span<byte> destination, Half value)
         }
 
         /// <summary>
-        /// Writes an Int16 into a span of bytes as little endian.
+        /// Writes a <see cref="short" /> into a span of bytes, as little endian.
         /// </summary>
         /// <returns>If the span is too small to contain the value, return false.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -241,7 +311,7 @@ public static bool TryWriteInt16LittleEndian(Span<byte> destination, short value
         }
 
         /// <summary>
-        /// Writes an Int32 into a span of bytes as little endian.
+        /// Writes a <see cref="int" /> into a span of bytes, as little endian.
         /// </summary>
         /// <returns>If the span is too small to contain the value, return false.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -257,7 +327,7 @@ public static bool TryWriteInt32LittleEndian(Span<byte> destination, int value)
         }
 
         /// <summary>
-        /// Writes an Int64 into a span of bytes as little endian.
+        /// Writes a <see cref="long" /> into a span of bytes, as little endian.
         /// </summary>
         /// <returns>If the span is too small to contain the value, return false.</returns>
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -272,6 +342,38 @@ public static bool TryWriteInt64LittleEndian(Span<byte> destination, long value)
             return MemoryMarshal.TryWrite(destination, ref value);
         }
 
+        /// <summary>
+        /// Writes a <see cref="Int128" /> into a span of bytes, as little endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain the value, return false.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryWriteInt128LittleEndian(Span<byte> destination, Int128 value)
+        {
+            if (!BitConverter.IsLittleEndian)
+            {
+                Int128 tmp = ReverseEndianness(value);
+                return MemoryMarshal.TryWrite(destination, ref tmp);
+            }
+
+            return MemoryMarshal.TryWrite(destination, ref value);
+        }
+
+        /// <summary>
+        /// Writes a <see cref="nint" /> into a span of bytes, as little endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain the value, return false.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryWriteIntPtrLittleEndian(Span<byte> destination, nint value)
+        {
+            if (!BitConverter.IsLittleEndian)
+            {
+                nint tmp = ReverseEndianness(value);
+                return MemoryMarshal.TryWrite(destination, ref tmp);
+            }
+
+            return MemoryMarshal.TryWrite(destination, ref value);
+        }
+
         /// <summary>
         /// Writes a <see cref="float" /> into a span of bytes, as little endian.
         /// </summary>
@@ -294,7 +396,7 @@ public static bool TryWriteSingleLittleEndian(Span<byte> destination, float valu
         }
 
         /// <summary>
-        /// Write a UInt16 into a span of bytes as little endian.
+        /// Write a <see cref="ushort" /> into a span of bytes, as little endian.
         /// </summary>
         /// <returns>If the span is too small to contain the value, return false.</returns>
         [CLSCompliant(false)]
@@ -311,7 +413,7 @@ public static bool TryWriteUInt16LittleEndian(Span<byte> destination, ushort val
         }
 
         /// <summary>
-        /// Write a UInt32 into a span of bytes as little endian.
+        /// Write a <see cref="uint" /> into a span of bytes, as little endian.
         /// </summary>
         /// <returns>If the span is too small to contain the value, return false.</returns>
         [CLSCompliant(false)]
@@ -328,7 +430,7 @@ public static bool TryWriteUInt32LittleEndian(Span<byte> destination, uint value
         }
 
         /// <summary>
-        /// Write a UInt64 into a span of bytes as little endian.
+        /// Write a <see cref="ulong" /> into a span of bytes, as little endian.
         /// </summary>
         /// <returns>If the span is too small to contain the value, return false.</returns>
         [CLSCompliant(false)]
@@ -343,5 +445,39 @@ public static bool TryWriteUInt64LittleEndian(Span<byte> destination, ulong valu
 
             return MemoryMarshal.TryWrite(destination, ref value);
         }
+
+        /// <summary>
+        /// Writes a <see cref="UInt128" /> into a span of bytes, as little endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain the value, return false.</returns>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryWriteUInt128LittleEndian(Span<byte> destination, UInt128 value)
+        {
+            if (!BitConverter.IsLittleEndian)
+            {
+                UInt128 tmp = ReverseEndianness(value);
+                return MemoryMarshal.TryWrite(destination, ref tmp);
+            }
+
+            return MemoryMarshal.TryWrite(destination, ref value);
+        }
+
+        /// <summary>
+        /// Writes a <see cref="nuint" /> into a span of bytes, as little endian.
+        /// </summary>
+        /// <returns>If the span is too small to contain the value, return false.</returns>
+        [CLSCompliant(false)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool TryWriteUIntPtrLittleEndian(Span<byte> destination, nuint value)
+        {
+            if (!BitConverter.IsLittleEndian)
+            {
+                nuint tmp = ReverseEndianness(value);
+                return MemoryMarshal.TryWrite(destination, ref tmp);
+            }
+
+            return MemoryMarshal.TryWrite(destination, ref value);
+        }
     }
 }
diff --git a/src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventPipePayloadDecoder.cs b/src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventPipePayloadDecoder.cs
index a5c396cb207f0..ae97271568458 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventPipePayloadDecoder.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/EventPipePayloadDecoder.cs
@@ -31,14 +31,7 @@ internal static object[] DecodePayload(ref EventSource.EventMetadata metadata, R
                 Type? enumType = parameterType.IsEnum ? Enum.GetUnderlyingType(parameterType) : null;
                 if (parameterType == typeof(IntPtr))
                 {
-                    if (IntPtr.Size == 8)
-                    {
-                        decodedFields[i] = (nint)BinaryPrimitives.ReadInt64LittleEndian(payload);
-                    }
-                    else
-                    {
-                        decodedFields[i] = (nint)BinaryPrimitives.ReadInt32LittleEndian(payload);
-                    }
+                    decodedFields[i] = BinaryPrimitives.ReadIntPtrLittleEndian(payload);
                     payload = payload.Slice(IntPtr.Size);
                 }
                 else if (parameterType == typeof(int) || enumType == typeof(int))
@@ -83,12 +76,12 @@ internal static object[] DecodePayload(ref EventSource.EventMetadata metadata, R
                 }
                 else if (parameterType == typeof(float))
                 {
-                    decodedFields[i] = BitConverter.Int32BitsToSingle(BinaryPrimitives.ReadInt32LittleEndian(payload));
+                    decodedFields[i] = BinaryPrimitives.ReadSingleLittleEndian(payload);
                     payload = payload.Slice(sizeof(float));
                 }
                 else if (parameterType == typeof(double))
                 {
-                    decodedFields[i] = BitConverter.Int64BitsToDouble(BinaryPrimitives.ReadInt64LittleEndian(payload));
+                    decodedFields[i] = BinaryPrimitives.ReadDoubleLittleEndian(payload);
                     payload = payload.Slice(sizeof(double));
                 }
                 else if (parameterType == typeof(bool))
diff --git a/src/libraries/System.Private.CoreLib/src/System/IO/BinaryReader.cs b/src/libraries/System.Private.CoreLib/src/System/IO/BinaryReader.cs
index 0033453e93e0e..fe353d35e1c3a 100644
--- a/src/libraries/System.Private.CoreLib/src/System/IO/BinaryReader.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/IO/BinaryReader.cs
@@ -240,9 +240,9 @@ public virtual char ReadChar()
         public virtual long ReadInt64() => BinaryPrimitives.ReadInt64LittleEndian(InternalRead(8));
         [CLSCompliant(false)]
         public virtual ulong ReadUInt64() => BinaryPrimitives.ReadUInt64LittleEndian(InternalRead(8));
-        public virtual Half ReadHalf() => BitConverter.Int16BitsToHalf(BinaryPrimitives.ReadInt16LittleEndian(InternalRead(2)));
-        public virtual unsafe float ReadSingle() => BitConverter.Int32BitsToSingle(BinaryPrimitives.ReadInt32LittleEndian(InternalRead(4)));
-        public virtual unsafe double ReadDouble() => BitConverter.Int64BitsToDouble(BinaryPrimitives.ReadInt64LittleEndian(InternalRead(8)));
+        public virtual Half ReadHalf() => BinaryPrimitives.ReadHalfLittleEndian(InternalRead(2));
+        public virtual float ReadSingle() => BinaryPrimitives.ReadSingleLittleEndian(InternalRead(4));
+        public virtual double ReadDouble() => BinaryPrimitives.ReadDoubleLittleEndian(InternalRead(8));
 
         public virtual decimal ReadDecimal()
         {