Fixed a bug with readback_resolve and readback_memexport that was responsible for a large portion of their overhead. readback_memexport and resolve are now usable for games, depending on your hardware. in my case games that were slideshows now run at like 20-30 fps, and my hardware isnt the best for xenia.

add split_map class for mapping keys to values in a way that optimizes for frequent searches and infrequent insertions/removals
remove jump table implementation of GetColorRenderTargetFormatComponentCount, it was appearing relatively high in profiles. instead pack the component counts into a single 32 bit word, which is indexed by shifting
Add cvar to align all basic blocks to a boundary
Add mmio aware load paths
liberally apply XE_RESTRICT in ringbuffer related code
Removed the IS_TRUE and IS_FALSE opcodes, they were pointless duplicates of COMPARE_EQ/COMPARE_NE and i want to simplify our set of opcodes for future backends
More work on LVSR/LVSL/STVR/STVL opcodes
Optimized X64 translated code emission, now only compute instrkey once
Add code for pre-computing integer division magic numbers
Optimized GetHostViewportInfo a little
Move args for GetHostViewportInfo into a class, cache the result and compare for future queries. moved GetHostViewportInfo far lower on the profile
Add (currently not functional, and very racy) asynchronous memcpy code. will improve it and actually use it in future commits.
Add non-temporal memcpy function for huge page-aligned allocations. Used for copying to shared memory/readback
hoist are_accumulated_render_targets_valid_ check out of loop in render_target_cache already bound check.
Add stosb/movsb code for small constant memcpys/memsets that arent worth the overhead of memcpy/memset

src/xenia/base/dma.h

@@ -0,0 +1,46 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2020 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#ifndef XENIA_BASE_DMA_H_
+#define XENIA_BASE_DMA_H_
+#include "memory.h"
+#include "threading.h"
+namespace xe::dma {
+struct XeDMAJob;
+using DmaPrecall = void (*)(XeDMAJob* job);
+using DmaPostcall = void (*)(XeDMAJob* job);
+struct XeDMAJob {
+  threading::Event* signal_on_done;
+  uint8_t* destination;
+  uint8_t* source;
+  size_t size;
+  DmaPrecall precall;
+  DmaPostcall postcall;
+  void* userdata1;
+  void* userdata2;
+};
+using DMACJobHandle = uint64_t;
+
+class XeDMAC {
+ public:
+  virtual ~XeDMAC() {}
+  virtual DMACJobHandle PushDMAJob(XeDMAJob* job) = 0;
+  virtual void WaitJobDone(DMACJobHandle handle) = 0;
+  virtual void WaitForIdle() = 0;
+};
+
+XeDMAC* CreateDMAC();
+// must be divisible by cache line size
+XE_NOINLINE
+void vastcpy(uint8_t* XE_RESTRICT physaddr, uint8_t* XE_RESTRICT rdmapping,
+             uint32_t written_length);
+
+}  // namespace xe::dma
+
+#endif  // XENIA_BASE_DMA_H_