From 6d35e39f4f249c627c11586f4769361bde0ed62d Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Tue, 16 Jan 2024 17:14:57 -0800
Subject: [PATCH] [release/8.0-staging] UInt64.CreateSaturating<Int128>
 truncates instead of saturates (#97047)

* UInt64.CreateSaturating<Int128> truncates instead of saturates

* Update src/libraries/System.Private.CoreLib/src/System/Int128.cs

---------

Co-authored-by: pedrobsaila <badrebsaila@outlook.com>
Co-authored-by: Stephen Toub <stoub@microsoft.com>
---
 src/libraries/System.Private.CoreLib/src/System/Int128.cs      | 3 ++-
 .../System.Runtime/tests/System/UInt64Tests.GenericMath.cs     | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/libraries/System.Private.CoreLib/src/System/Int128.cs b/src/libraries/System.Private.CoreLib/src/System/Int128.cs
index 50dce177e17135..fae7c1b441457b 100644
--- a/src/libraries/System.Private.CoreLib/src/System/Int128.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Int128.cs
@@ -1899,7 +1899,8 @@ static bool INumberBase<Int128>.TryConvertToSaturating<TOther>(Int128 value, [Ma
             }
             else if (typeof(TOther) == typeof(ulong))
             {
-                ulong actualResult = (value <= 0) ? ulong.MinValue : (ulong)value;
+                ulong actualResult = (value >= ulong.MaxValue) ? ulong.MaxValue :
+                                     (value <= ulong.MinValue) ? ulong.MinValue : (ulong)value;
                 result = (TOther)(object)actualResult;
                 return true;
             }
diff --git a/src/libraries/System.Runtime/tests/System/UInt64Tests.GenericMath.cs b/src/libraries/System.Runtime/tests/System/UInt64Tests.GenericMath.cs
index 89639038fd4eeb..614dd54b10255e 100644
--- a/src/libraries/System.Runtime/tests/System/UInt64Tests.GenericMath.cs
+++ b/src/libraries/System.Runtime/tests/System/UInt64Tests.GenericMath.cs
@@ -1642,6 +1642,7 @@ public static void CreateSaturatingFromInt128Test()
             Assert.Equal((ulong)0xFFFF_FFFF_FFFF_FFFF, NumberBaseHelper<ulong>.CreateSaturating<Int128>(Int128.MaxValue));
             Assert.Equal((ulong)0x0000_0000_0000_0000, NumberBaseHelper<ulong>.CreateSaturating<Int128>(Int128.MinValue));
             Assert.Equal((ulong)0x0000_0000_0000_0000, NumberBaseHelper<ulong>.CreateSaturating<Int128>(Int128.NegativeOne));
+            Assert.Equal((ulong)0xFFFF_FFFF_FFFF_FFFF, NumberBaseHelper<ulong>.CreateSaturating<Int128>((Int128)ulong.MaxValue + (Int128)10L));
         }
 
         [Fact]