From 47d0d292d5cc5f0404e126023279db7decd532ac Mon Sep 17 00:00:00 2001
From: Fernando Sahmkow <fsahmkow27@gmail.com>
Date: Wed, 28 Jun 2023 06:28:13 +0200
Subject: MemoryTracking: Initial setup of atomic writes.

---
 src/core/gpu_dirty_memory_manager.h | 112 ++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 src/core/gpu_dirty_memory_manager.h

(limited to 'src/core/gpu_dirty_memory_manager.h')

diff --git a/src/core/gpu_dirty_memory_manager.h b/src/core/gpu_dirty_memory_manager.h
new file mode 100644
index 000000000..9c3d41d11
--- /dev/null
+++ b/src/core/gpu_dirty_memory_manager.h
@@ -0,0 +1,112 @@
+#pragma once
+
+#include <atomic>
+#include <bit>
+#include <functional>
+#include <mutex>
+#include <utility>
+#include <vector>
+
+#include "core/memory.h"
+
+namespace Core {
+
+class GPUDirtyMemoryManager {
+public:
+    GPUDirtyMemoryManager() : current{default_transform} {}
+
+    ~GPUDirtyMemoryManager() = default;
+
+    void Collect(VAddr address, size_t size) {
+        TransformAddress t = BuildTransform(address, size);
+        TransformAddress tmp, original;
+        do {
+            tmp = current.load(std::memory_order_acquire);
+            original = tmp;
+            if (tmp.address != t.address) {
+                if (IsValid(tmp.address)) {
+                    std::scoped_lock lk(guard);
+                    back_buffer.emplace_back(tmp);
+                    current.exchange(t, std::memory_order_relaxed);
+                    return;
+                }
+                tmp.address = t.address;
+                tmp.mask = 0;
+            }
+            if ((tmp.mask | t.mask) == tmp.mask) {
+                return;
+            }
+            tmp.mask |= t.mask;
+        } while (!current.compare_exchange_weak(original, tmp, std::memory_order_release,
+                                                std::memory_order_relaxed));
+    }
+
+    void Gather(std::function<void(VAddr, size_t)>& callback) {
+        {
+            std::scoped_lock lk(guard);
+            TransformAddress t = current.exchange(default_transform, std::memory_order_relaxed);
+            front_buffer.swap(back_buffer);
+            if (IsValid(t.address)) {
+                front_buffer.emplace_back(t);
+            }
+        }
+        for (auto& transform : front_buffer) {
+            size_t offset = 0;
+            u64 mask = transform.mask;
+            while (mask != 0) {
+                const size_t empty_bits = std::countr_zero(mask);
+                offset += empty_bits << align_bits;
+                mask = mask >> empty_bits;
+
+                const size_t continuous_bits = std::countr_one(mask);
+                callback((transform.address << Memory::YUZU_PAGEBITS) + offset,
+                         continuous_bits << align_bits);
+                mask = continuous_bits < align_size ? (mask >> continuous_bits) : 0;
+                offset += continuous_bits << align_bits;
+            }
+        }
+        front_buffer.clear();
+    }
+
+private:
+    struct alignas(16) TransformAddress {
+        VAddr address;
+        u64 mask;
+    };
+
+    constexpr static size_t align_bits = 6U;
+    constexpr static size_t align_size = 1U << align_bits;
+    constexpr static size_t align_mask = align_size - 1;
+    constexpr static TransformAddress default_transform = {.address = ~0ULL, .mask = 0ULL};
+
+    bool IsValid(VAddr address) {
+        return address < (1ULL << 39);
+    }
+
+    template <typename T>
+    T CreateMask(size_t top_bit, size_t minor_bit) {
+        T mask = ~T(0);
+        mask <<= (sizeof(T) * 8 - top_bit);
+        mask >>= (sizeof(T) * 8 - top_bit);
+        mask >>= minor_bit;
+        mask <<= minor_bit;
+        return mask;
+    }
+
+    TransformAddress BuildTransform(VAddr address, size_t size) {
+        const size_t minor_address = address & Memory::YUZU_PAGEMASK;
+        const size_t minor_bit = minor_address >> align_bits;
+        const size_t top_bit = (minor_address + size + align_mask) >> align_bits;
+        TransformAddress result{};
+        result.address = address >> Memory::YUZU_PAGEBITS;
+        result.mask = CreateMask<u64>(top_bit, minor_bit);
+        return result;
+    }
+
+    std::atomic<TransformAddress> current{};
+    std::mutex guard;
+    std::vector<TransformAddress> back_buffer;
+    std::vector<TransformAddress> front_buffer;
+};
+
+} // namespace Core
-- 
cgit v1.2.3