1 files changed, 218 insertions, 0 deletions

diff --git a/src/core/guest_memory.h b/src/core/guest_memory.h
new file mode 100644
index 000000000..0b349cc17
--- /dev/null
+++ b/src/core/guest_memory.h
@@ -0,0 +1,218 @@
+// SPDX-FileCopyrightText: Copyright 2023 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <iterator>
+#include <memory>
+#include <optional>
+#include <span>
+#include <vector>
+
+#include "common/scratch_buffer.h"
+#include "core/memory.h"
+
+namespace Core::Memory {
+
+enum GuestMemoryFlags : u32 {
+    Read = 1 << 0,
+    Write = 1 << 1,
+    Safe = 1 << 2,
+    Cached = 1 << 3,
+
+    SafeRead = Read | Safe,
+    SafeWrite = Write | Safe,
+    SafeReadWrite = SafeRead | SafeWrite,
+    SafeReadCachedWrite = SafeReadWrite | Cached,
+
+    UnsafeRead = Read,
+    UnsafeWrite = Write,
+    UnsafeReadWrite = UnsafeRead | UnsafeWrite,
+    UnsafeReadCachedWrite = UnsafeReadWrite | Cached,
+};
+
+namespace {
+template <typename M, typename T, GuestMemoryFlags FLAGS>
+class GuestMemory {
+    using iterator = T*;
+    using const_iterator = const T*;
+    using value_type = T;
+    using element_type = T;
+    using iterator_category = std::contiguous_iterator_tag;
+
+public:
+    GuestMemory() = delete;
+    explicit GuestMemory(M& memory, u64 addr, std::size_t size,
+                         Common::ScratchBuffer<T>* backup = nullptr)
+        : m_memory{memory}, m_addr{addr}, m_size{size} {
+        static_assert(FLAGS & GuestMemoryFlags::Read || FLAGS & GuestMemoryFlags::Write);
+        if constexpr (FLAGS & GuestMemoryFlags::Read) {
+            Read(addr, size, backup);
+        }
+    }
+
+    ~GuestMemory() = default;
+
+    T* data() noexcept {
+        return m_data_span.data();
+    }
+
+    const T* data() const noexcept {
+        return m_data_span.data();
+    }
+
+    size_t size() const noexcept {
+        return m_size;
+    }
+
+    size_t size_bytes() const noexcept {
+        return this->size() * sizeof(T);
+    }
+
+    [[nodiscard]] T* begin() noexcept {
+        return this->data();
+    }
+
+    [[nodiscard]] const T* begin() const noexcept {
+        return this->data();
+    }
+
+    [[nodiscard]] T* end() noexcept {
+        return this->data() + this->size();
+    }
+
+    [[nodiscard]] const T* end() const noexcept {
+        return this->data() + this->size();
+    }
+
+    T& operator[](size_t index) noexcept {
+        return m_data_span[index];
+    }
+
+    const T& operator[](size_t index) const noexcept {
+        return m_data_span[index];
+    }
+
+    void SetAddressAndSize(u64 addr, std::size_t size) noexcept {
+        m_addr = addr;
+        m_size = size;
+        m_addr_changed = true;
+    }
+
+    std::span<T> Read(u64 addr, std::size_t size,
+                      Common::ScratchBuffer<T>* backup = nullptr) noexcept {
+        m_addr = addr;
+        m_size = size;
+        if (m_size == 0) {
+            m_is_data_copy = true;
+            return {};
+        }
+
+        if (this->TrySetSpan()) {
+            if constexpr (FLAGS & GuestMemoryFlags::Safe) {
+                m_memory.FlushRegion(m_addr, this->size_bytes());
+            }
+        } else {
+            if (backup) {
+                backup->resize_destructive(this->size());
+                m_data_span = *backup;
+            } else {
+                m_data_copy.resize(this->size());
+                m_data_span = std::span(m_data_copy);
+            }
+            m_is_data_copy = true;
+            m_span_valid = true;
+            if constexpr (FLAGS & GuestMemoryFlags::Safe) {
+                m_memory.ReadBlock(m_addr, this->data(), this->size_bytes());
+            } else {
+                m_memory.ReadBlockUnsafe(m_addr, this->data(), this->size_bytes());
+            }
+        }
+        return m_data_span;
+    }
+
+    void Write(std::span<T> write_data) noexcept {
+        if constexpr (FLAGS & GuestMemoryFlags::Cached) {
+            m_memory.WriteBlockCached(m_addr, write_data.data(), this->size_bytes());
+        } else if constexpr (FLAGS & GuestMemoryFlags::Safe) {
+            m_memory.WriteBlock(m_addr, write_data.data(), this->size_bytes());
+        } else {
+            m_memory.WriteBlockUnsafe(m_addr, write_data.data(), this->size_bytes());
+        }
+    }
+
+    bool TrySetSpan() noexcept {
+        if (u8* ptr = m_memory.GetSpan(m_addr, this->size_bytes()); ptr) {
+            m_data_span = {reinterpret_cast<T*>(ptr), this->size()};
+            m_span_valid = true;
+            return true;
+        }
+        return false;
+    }
+
+protected:
+    bool IsDataCopy() const noexcept {
+        return m_is_data_copy;
+    }
+
+    bool AddressChanged() const noexcept {
+        return m_addr_changed;
+    }
+
+    M& m_memory;
+    u64 m_addr{};
+    size_t m_size{};
+    std::span<T> m_data_span{};
+    std::vector<T> m_data_copy{};
+    bool m_span_valid{false};
+    bool m_is_data_copy{false};
+    bool m_addr_changed{false};
+};
+
+template <typename M, typename T, GuestMemoryFlags FLAGS>
+class GuestMemoryScoped : public GuestMemory<M, T, FLAGS> {
+public:
+    GuestMemoryScoped() = delete;
+    explicit GuestMemoryScoped(M& memory, u64 addr, std::size_t size,
+                               Common::ScratchBuffer<T>* backup = nullptr)
+        : GuestMemory<M, T, FLAGS>(memory, addr, size, backup) {
+        if constexpr (!(FLAGS & GuestMemoryFlags::Read)) {
+            if (!this->TrySetSpan()) {
+                if (backup) {
+                    this->m_data_span = *backup;
+                    this->m_span_valid = true;
+                    this->m_is_data_copy = true;
+                }
+            }
+        }
+    }
+
+    ~GuestMemoryScoped() {
+        if constexpr (FLAGS & GuestMemoryFlags::Write) {
+            if (this->size() == 0) [[unlikely]] {
+                return;
+            }
+
+            if (this->AddressChanged() || this->IsDataCopy()) {
+                ASSERT(this->m_span_valid);
+                if constexpr (FLAGS & GuestMemoryFlags::Cached) {
+                    this->m_memory.WriteBlockCached(this->m_addr, this->data(), this->size_bytes());
+                } else if constexpr (FLAGS & GuestMemoryFlags::Safe) {
+                    this->m_memory.WriteBlock(this->m_addr, this->data(), this->size_bytes());
+                } else {
+                    this->m_memory.WriteBlockUnsafe(this->m_addr, this->data(), this->size_bytes());
+                }
+            } else if constexpr ((FLAGS & GuestMemoryFlags::Safe) || (FLAGS & GuestMemoryFlags::Cached))  {
+                this->m_memory.InvalidateRegion(this->m_addr, this->size_bytes());
+            }
+        }
+    }
+};
+} // namespace
+
+template <typename T, GuestMemoryFlags FLAGS>
+using CpuGuestMemory = GuestMemory<Core::Memory::Memory, T, FLAGS>;
+template <typename T, GuestMemoryFlags FLAGS>
+using CpuGuestMemoryScoped = GuestMemoryScoped<Core::Memory::Memory, T, FLAGS>;
+
+} // namespace Tegra::Memory