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/kernel/xboxkrnl/xboxkrnl_hal.cc

@@ -0,0 +1,64 @@
+/**
+ ******************************************************************************
+ * 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/kernel/xboxkrnl/xboxkrnl_hal.h>
+
+#include <xenia/kernel/shim_utils.h>
+#include <xenia/kernel/xboxkrnl/kernel_state.h>
+#include <xenia/kernel/xboxkrnl/xboxkrnl_private.h>
+
+
+using namespace xe;
+using namespace xe::kernel;
+using namespace xe::kernel::xboxkrnl;
+
+
+namespace xe {
+namespace kernel {
+namespace xboxkrnl {
+
+
+void xeHalReturnToFirmware(uint32_t routine) {
+  KernelState* state = shared_kernel_state_;
+  XEASSERTNOTNULL(state);
+
+  // void
+  // IN FIRMWARE_REENTRY  Routine
+
+  // Routine must be 1 'HalRebootRoutine'
+  XEASSERT(routine == 1);
+
+  // TODO(benvank): diediedie much more gracefully
+  // Not sure how to blast back up the stack in LLVM without exceptions, though.
+  XELOGE("Game requested shutdown via HalReturnToFirmware");
+  exit(0);
+}
+
+
+SHIM_CALL HalReturnToFirmware_shim(
+    xe_ppc_state_t* ppc_state, KernelState* state) {
+  uint32_t routine = SHIM_GET_ARG_32(0);
+
+  XELOGD(
+      "HalReturnToFirmware(%d)",
+      routine);
+
+  xeHalReturnToFirmware(routine);
+}
+
+
+}  // namespace xboxkrnl
+}  // namespace kernel
+}  // namespace xe
+
+
+void xe::kernel::xboxkrnl::RegisterHalExports(
+    ExportResolver* export_resolver, KernelState* state) {
+  SHIM_SET_MAPPING("xboxkrnl.exe", HalReturnToFirmware, state);
+}