Massive refactoring of all code + audio skeleton.

This should make it easier to find files and (in the future) split things
up into separate libraries.
It also changes around emulator initialization to make it a little more
difficult to do things out of order and a little more sensible as to when
real init work happens.
Also adding a skeleton audio system/driver and reworking CPU register
access to be more extensible.

src/xenia/apu/audio_system.cc

@@ -0,0 +1,116 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2013 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#include <xenia/apu/audio_system.h>
+
+#include <xenia/emulator.h>
+#include <xenia/cpu/processor.h>
+#include <xenia/apu/audio_driver.h>
+
+
+using namespace xe;
+using namespace xe::apu;
+using namespace xe::cpu::ppc;
+
+
+AudioSystem::AudioSystem(Emulator* emulator) :
+    emulator_(emulator),
+    thread_(0), running_(false), driver_(0) {
+  memory_ = xe_memory_retain(emulator->memory());
+
+  // Create the run loop used for any windows/etc.
+  // This must be done on the thread we create the driver.
+  run_loop_ = xe_run_loop_create();
+}
+
+AudioSystem::~AudioSystem() {
+  // TODO(benvanik): thread join.
+  running_ = false;
+  xe_thread_release(thread_);
+
+  xe_run_loop_release(run_loop_);
+  xe_memory_release(memory_);
+}
+
+X_STATUS AudioSystem::Setup() {
+  processor_ = emulator_->processor();
+
+  // Let the processor know we want register access callbacks.
+  RegisterAccessCallbacks callbacks;
+  callbacks.context = this;
+  callbacks.handles = (RegisterHandlesCallback)HandlesRegisterThunk;
+  callbacks.read    = (RegisterReadCallback)ReadRegisterThunk;
+  callbacks.write   = (RegisterWriteCallback)WriteRegisterThunk;
+  emulator_->processor()->AddRegisterAccessCallbacks(callbacks);
+
+  // Create worker thread.
+  // This will initialize the audio system.
+  // Init needs to happen there so that any thread-local stuff
+  // is created on the right thread.
+  running_ = true;
+  thread_ = xe_thread_create(
+      "AudioSystem",
+      (xe_thread_callback)ThreadStartThunk, this);
+  xe_thread_start(thread_);
+
+  return X_STATUS_SUCCESS;
+}
+
+void AudioSystem::ThreadStart() {
+  xe_run_loop_ref run_loop = xe_run_loop_retain(run_loop_);
+
+  // Initialize driver and ringbuffer.
+  Initialize();
+  XEASSERTNOTNULL(driver_);
+
+  // Main run loop.
+  while (running_) {
+    // Peek main run loop.
+    if (xe_run_loop_pump(run_loop)) {
+      break;
+    }
+    if (!running_) {
+      break;
+    }
+
+    // Pump worker.
+    //worker_->Pump();
+
+    // Pump audio system.
+    Pump();
+  }
+  running_ = false;
+
+  Shutdown();
+
+  xe_run_loop_release(run_loop);
+
+  // TODO(benvanik): call module API to kill?
+}
+
+void AudioSystem::Initialize() {
+}
+
+void AudioSystem::Shutdown() {
+}
+
+bool AudioSystem::HandlesRegister(uint32_t addr) {
+  return (addr & 0xFFFF0000) == 0x7FEA0000;
+}
+
+uint64_t AudioSystem::ReadRegister(uint32_t addr) {
+  uint32_t r = addr & 0xFFFF;
+  XELOGAPU("ReadRegister(%.4X)", r);
+  return 0;
+}
+
+void AudioSystem::WriteRegister(uint32_t addr, uint64_t value) {
+  uint32_t r = addr & 0xFFFF;
+  XELOGAPU("WriteRegister(%.4X, %.8X)", r, value);
+}