JitArm64: Implement frsqrte

Source/UnitTests/Core/CMakeLists.txt

@@ -26,6 +26,7 @@ elseif(_M_ARM_64)
     PowerPC/JitArm64/ConvertSingleDouble.cpp
     PowerPC/JitArm64/FPRF.cpp
     PowerPC/JitArm64/Fres.cpp
+    PowerPC/JitArm64/Frsqrte.cpp
     PowerPC/JitArm64/MovI2R.cpp
   )
 else()

Source/UnitTests/Core/PowerPC/JitArm64/Frsqrte.cpp

@@ -0,0 +1,66 @@
+// Copyright 2021 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#include <functional>
+
+#include "Common/Arm64Emitter.h"
+#include "Common/BitUtils.h"
+#include "Common/CommonTypes.h"
+#include "Core/PowerPC/Interpreter/Interpreter_FPUtils.h"
+#include "Core/PowerPC/JitArm64/Jit.h"
+#include "Core/PowerPC/PowerPC.h"
+
+#include "../TestValues.h"
+
+#include <gtest/gtest.h>
+
+namespace
+{
+using namespace Arm64Gen;
+
+class TestFrsqrte : public JitArm64
+{
+public:
+  TestFrsqrte()
+  {
+    AllocCodeSpace(4096);
+
+    const u8* raw_frsqrte = GetCodePtr();
+    GenerateFrsqrte();
+
+    frsqrte = Common::BitCast<u64 (*)(u64)>(GetCodePtr());
+    MOV(ARM64Reg::X15, ARM64Reg::X30);
+    MOV(ARM64Reg::X14, PPC_REG);
+    MOVP2R(PPC_REG, &PowerPC::ppcState);
+    MOV(ARM64Reg::X1, ARM64Reg::X0);
+    m_float_emit.FMOV(ARM64Reg::D0, ARM64Reg::X0);
+    m_float_emit.FRSQRTE(ARM64Reg::D0, ARM64Reg::D0);
+    BL(raw_frsqrte);
+    MOV(ARM64Reg::X30, ARM64Reg::X15);
+    MOV(PPC_REG, ARM64Reg::X14);
+    RET();
+  }
+
+  std::function<u64(u64)> frsqrte;
+};
+
+}  // namespace
+
+TEST(JitArm64, Frsqrte)
+{
+  TestFrsqrte test;
+
+  for (const u64 ivalue : double_test_values)
+  {
+    const double dvalue = Common::BitCast<double>(ivalue);
+
+    const u64 expected = Common::BitCast<u64>(Common::ApproximateReciprocalSquareRoot(dvalue));
+    const u64 actual = test.frsqrte(ivalue);
+
+    if (expected != actual)
+      fmt::print("{:016x} -> {:016x} == {:016x}\n", ivalue, actual, expected);
+
+    EXPECT_EQ(expected, actual);
+  }
+}

Source/UnitTests/UnitTests.vcxproj

@@ -85,6 +85,7 @@
     <ClCompile Include="Core\PowerPC\JitArm64\ConvertSingleDouble.cpp" />
     <ClCompile Include="Core\PowerPC\JitArm64\FPRF.cpp" />
     <ClCompile Include="Core\PowerPC\JitArm64\Fres.cpp" />
+    <ClCompile Include="Core\PowerPC\JitArm64\Frsqrte.cpp" />
     <ClCompile Include="Core\PowerPC\JitArm64\MovI2R.cpp" />
   </ItemGroup>
   <ItemGroup>