初始化内容

third/JoltPhysics/UnitTests/Core/PreciseMathTest.cpp

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+// Jolt Physics Library (https://github.com/jrouwe/JoltPhysics)
+// SPDX-FileCopyrightText: 2023 Jorrit Rouwe
+// SPDX-License-Identifier: MIT
+
+#include "UnitTestFramework.h"
+#include <atomic>
+
+// Implemented as a global atomic so the compiler can't optimize it to a constant
+extern atomic<float> One, OneTenth, Ten;
+atomic<float> One = 1.0f, OneTenth = 0.1f /* Actually: 0.100000001f */, Ten = 10.0f;
+
+JPH_PRECISE_MATH_ON
+
+TEST_SUITE("PreciseMathTest")
+{
+	TEST_CASE("CheckNoFMA")
+	{
+		// Should not use the FMA instruction and end up being zero
+		// If FMA is active, a * b will not be rounded to 1.0f so the result will be a small positive number
+		float a = OneTenth, b = Ten, c = One;
+		float result = a * b - c;
+		CHECK(result == 0.0f);
+
+		// Compiler should not optimize these variables away
+		One = OneTenth = Ten = 2.0f;
+	}
+}
+
+JPH_PRECISE_MATH_OFF