From 60a119da6ac188dc9f4df77163cb327b4c85b25e Mon Sep 17 00:00:00 2001
From: Merry <git@mary.rs>
Date: Tue, 2 Aug 2022 00:33:59 +0100
Subject: [PATCH] backend: Implement FpsrManager

---
 src/dynarmic/CMakeLists.txt                 |  2 ++
 src/dynarmic/backend/arm64/fpsr_manager.cpp | 40 +++++++++++++++++++++
 src/dynarmic/backend/arm64/fpsr_manager.h   | 33 +++++++++++++++++
 3 files changed, 75 insertions(+)
 create mode 100644 src/dynarmic/backend/arm64/fpsr_manager.cpp
 create mode 100644 src/dynarmic/backend/arm64/fpsr_manager.h

diff --git a/src/dynarmic/CMakeLists.txt b/src/dynarmic/CMakeLists.txt
index b033e7c1..a81fb0bc 100644
--- a/src/dynarmic/CMakeLists.txt
+++ b/src/dynarmic/CMakeLists.txt
@@ -390,6 +390,8 @@ elseif(ARCHITECTURE STREQUAL "arm64")
         backend/arm64/emit_arm64_vector_floating_point.cpp
         backend/arm64/emit_arm64_vector_saturation.cpp
         backend/arm64/emit_context.h
+        backend/arm64/fpsr_manager.cpp
+        backend/arm64/fpsr_manager.h
         backend/arm64/reg_alloc.cpp
         backend/arm64/reg_alloc.h
         backend/arm64/stack_layout.h
diff --git a/src/dynarmic/backend/arm64/fpsr_manager.cpp b/src/dynarmic/backend/arm64/fpsr_manager.cpp
new file mode 100644
index 00000000..8c697f5c
--- /dev/null
+++ b/src/dynarmic/backend/arm64/fpsr_manager.cpp
@@ -0,0 +1,40 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2022 MerryMage
+ * SPDX-License-Identifier: 0BSD
+ */
+
+#include "dynarmic/backend/arm64/fpsr_manager.h"
+
+#include <oaknut/oaknut.hpp>
+
+#include "dynarmic/backend/arm64/abi.h"
+
+namespace Dynarmic::Backend::Arm64 {
+
+using namespace oaknut::util;
+
+FpsrManager::FpsrManager(oaknut::CodeGenerator& code, size_t state_fpsr_offset)
+        : code{code}, state_fpsr_offset{state_fpsr_offset} {}
+
+void FpsrManager::Spill() {
+    if (!fpsr_loaded)
+        return;
+
+    code.LDR(Wscratch0, Xstate, state_fpsr_offset);
+    code.MSR(oaknut::SystemReg::FPSR, Xscratch1);
+    code.ORR(Wscratch0, Wscratch0, Wscratch1);
+    code.STR(Wscratch0, Xstate, state_fpsr_offset);
+
+    fpsr_loaded = false;
+}
+
+void FpsrManager::Load() {
+    if (fpsr_loaded)
+        return;
+
+    code.MRS(XZR, oaknut::SystemReg::FPSR);
+
+    fpsr_loaded = true;
+}
+
+}  // namespace Dynarmic::Backend::Arm64
diff --git a/src/dynarmic/backend/arm64/fpsr_manager.h b/src/dynarmic/backend/arm64/fpsr_manager.h
new file mode 100644
index 00000000..7aa22eab
--- /dev/null
+++ b/src/dynarmic/backend/arm64/fpsr_manager.h
@@ -0,0 +1,33 @@
+/* This file is part of the dynarmic project.
+ * Copyright (c) 2022 MerryMage
+ * SPDX-License-Identifier: 0BSD
+ */
+
+#pragma once
+
+#include <mcl/stdint.hpp>
+
+namespace oaknut {
+struct PointerCodeGeneratorPolicy;
+template<typename>
+class BasicCodeGenerator;
+using CodeGenerator = BasicCodeGenerator<PointerCodeGeneratorPolicy>;
+}  // namespace oaknut
+
+namespace Dynarmic::Backend::Arm64 {
+
+class FpsrManager {
+public:
+    explicit FpsrManager(oaknut::CodeGenerator& code, size_t state_fpsr_offset);
+
+    void Spill();
+    void Load();
+    void Overwrite() { fpsr_loaded = false; }
+
+private:
+    oaknut::CodeGenerator& code;
+    size_t state_fpsr_offset;
+    bool fpsr_loaded = false;
+};
+
+}  // namespace Dynarmic::Backend::Arm64