[D3D12] Shared memory - heap creation

src/xenia/gpu/d3d12/shared_memory.h

@@ -0,0 +1,65 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2018 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#ifndef XENIA_GPU_D3D12_SHARED_MEMORY_H_
+#define XENIA_GPU_D3D12_SHARED_MEMORY_H_
+
+#include "xenia/ui/d3d12/d3d12_api.h"
+#include "xenia/ui/d3d12/d3d12_context.h"
+
+namespace xe {
+namespace gpu {
+namespace d3d12 {
+
+// Manages memory for unconverted textures, resolve targets, vertex and index
+// buffers that can be accessed from shaders with Xenon physical addresses, with
+// 4 KB granularity.
+class SharedMemory {
+ public:
+  SharedMemory(ui::d3d12::D3D12Context* context);
+  ~SharedMemory();
+
+  bool Initialize();
+  void Shutdown();
+
+  // Ensures the backing memory for the address range is present in the tiled
+  // buffer, allocating if needed. If couldn't allocate, false is returned -
+  // it's unsafe to use this portion (on tiled resources tier 1 at least).
+  bool EnsureRangeAllocated(uint32_t start, uint32_t length);
+
+ private:
+  ui::d3d12::D3D12Context* context_ = nullptr;
+
+  // The 512 MB tiled buffer.
+  static constexpr uint32_t kBufferSizeLog2 = 29;
+  static constexpr uint32_t kBufferSize = 1 << kBufferSizeLog2;
+  static constexpr uint32_t kAddressMask = kBufferSize - 1;
+  ID3D12Resource* buffer_ = nullptr;
+  D3D12_RESOURCE_STATES buffer_state_ = D3D12_RESOURCE_STATE_COPY_DEST;
+
+  // D3D resource tiles are 64 KB in size.
+  static constexpr uint32_t kTileSizeLog2 = 16;
+  static constexpr uint32_t kTileSize = 1 << kTileSizeLog2;
+  // Heaps are 4 MB, so not too many of them are allocated.
+  static constexpr uint32_t kHeapSizeLog2 = 22;
+  static constexpr uint32_t kHeapSize = 1 << kHeapSizeLog2;
+  // Resident portions of the tiled buffer.
+  ID3D12Heap* heaps_[kBufferSize >> kHeapSizeLog2] = {};
+
+  // Log2 of system page size.
+  uint32_t page_size_log2_;
+  // Bit vector containing whether physical memory system pages are up to date.
+  std::vector<uint64_t> pages_in_sync_;
+};
+
+}  // namespace d3d12
+}  // namespace gpu
+}  // namespace xe
+
+#endif  // XENIA_GPU_D3D12_SHARED_MEMORY_H_