From 0bdf85730d732d74aa85b7f08d538eb2189ae61f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Lema=C5=84czyk?= <marek@lemanczyk.eu>
Date: Mon, 29 Sep 2025 23:28:35 +0200
Subject: [PATCH] Tiny optimization

---
 PerfectNumbers.Core/Gpu/GpuUInt128.cs | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/PerfectNumbers.Core/Gpu/GpuUInt128.cs b/PerfectNumbers.Core/Gpu/GpuUInt128.cs
index cf5cfb3..b21731f 100644
--- a/PerfectNumbers.Core/Gpu/GpuUInt128.cs
+++ b/PerfectNumbers.Core/Gpu/GpuUInt128.cs
@@ -22,7 +22,6 @@ public struct GpuUInt128 : IComparable<GpuUInt128>, IEquatable<GpuUInt128>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public GpuUInt128(ulong low)
     {
-        High = 0UL;
         Low = low;
     }
 
@@ -394,20 +393,25 @@ public struct GpuUInt128 : IComparable<GpuUInt128>, IEquatable<GpuUInt128>
 
         ulong w1 = xLow * yHigh;
         ulong w2 = xHigh * yLow;
-        ulong carry =
-            (((xLow * yLow) >> 32) +
-            (uint)w1 +
-            (uint)w2) >> 32;
-        return (xHigh * yHigh) + (w1 >> 32) + (w2 >> 32) + carry;
+        return (xHigh * yHigh) + (w1 >> 32) + (w2 >> 32) +
+        (
+            (
+                ((xLow * yLow) >> 32) +
+                (uint)w1 +
+                (uint)w2
+            ) >> 32
+        );
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public void Mul64(GpuUInt128 other)
     {
         // Multiply this.Low (assumed 64-bit value) by full 128-bit other
-        ulong operand = Low;
-        Low = operand * other.Low;
-        High = operand * other.High + MulHigh(operand, other.Low);
+        ulong operand = Low,
+              otherLow = other.Low;
+              
+        Low = operand * otherLow;
+        High = operand * other.High + MulHigh(operand, otherLow);
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]