/**
 ******************************************************************************
 * Xenia : Xbox 360 Emulator Research Project                                 *
 ******************************************************************************
 * Copyright 2022 Ben Vanik. All rights reserved.                             *
 * Released under the BSD license - see LICENSE in the root for more details. *
 ******************************************************************************
 */

#include "xenia/kernel/xboxkrnl/xboxkrnl_threading.h"
#include <algorithm>
#include <vector>
#include "xenia/base/atomic.h"
#include "xenia/base/clock.h"
#include "xenia/base/logging.h"
#include "xenia/base/mutex.h"
#include "xenia/cpu/processor.h"
#include "xenia/kernel/kernel_state.h"
#include "xenia/kernel/user_module.h"
#include "xenia/kernel/util/shim_utils.h"
#include "xenia/kernel/xboxkrnl/xboxkrnl_private.h"
#include "xenia/kernel/xevent.h"
#include "xenia/kernel/xmutant.h"
#include "xenia/kernel/xsemaphore.h"
#include "xenia/kernel/xthread.h"
#include "xenia/kernel/xtimer.h"
#include "xenia/xbox.h"

namespace xe {
namespace kernel {
namespace xboxkrnl {

// r13 + 0x100: pointer to thread local state
// Thread local state:
//   0x058: kernel time
//   0x14C: thread id
//   0x150: if >0 then error states don't get set
//   0x160: last error

// GetCurrentThreadId:
// lwz       r11, 0x100(r13)
// lwz       r3, 0x14C(r11)

// RtlGetLastError:
// lwz r11, 0x150(r13)
// if (r11 == 0) {
//   lwz r11, 0x100(r13)
//   stw r3, 0x160(r11)
// }

// RtlSetLastError:
// lwz r11, 0x150(r13)
// if (r11 == 0) {
//   lwz r11, 0x100(r13)
//   stw r3, 0x160(r11)
// }

// RtlSetLastNTError:
// r3 = RtlNtStatusToDosError(r3)
// lwz r11, 0x150(r13)
// if (r11 == 0) {
//   lwz r11, 0x100(r13)
//   stw r3, 0x160(r11)
// }

template <typename T>
object_ref<T> LookupNamedObject(KernelState* kernel_state,
                                uint32_t obj_attributes_ptr) {
  // If the name exists and its type matches, we can return that (ref+1)
  // with a success of NAME_EXISTS.
  // If the name exists and its type doesn't match, we do NAME_COLLISION.
  // Otherwise, we add like normal.
  if (!obj_attributes_ptr) {
    return nullptr;
  }
  auto obj_attributes =
      kernel_state->memory()->TranslateVirtual<X_OBJECT_ATTRIBUTES*>(
          obj_attributes_ptr);
  assert_true(obj_attributes->name_ptr != 0);
  auto name = util::TranslateAnsiStringAddress(kernel_state->memory(),
                                               obj_attributes->name_ptr);
  if (!name.empty()) {
    X_HANDLE handle = X_INVALID_HANDLE_VALUE;
    X_RESULT result =
        kernel_state->object_table()->GetObjectByName(name, &handle);
    if (XSUCCEEDED(result)) {
      // Found something! It's been retained, so return.
      auto obj = kernel_state->object_table()->LookupObject<T>(handle);
      if (obj) {
        // The caller will do as it likes.
        obj->ReleaseHandle();
        return obj;
      }
    }
  }
  return nullptr;
}

uint32_t ExCreateThread(xe::be<uint32_t>* handle_ptr, uint32_t stack_size,
                        xe::be<uint32_t>* thread_id_ptr,
                        uint32_t xapi_thread_startup, uint32_t start_address,
                        uint32_t start_context, uint32_t creation_flags) {
  // Invalid Link
  // http://jafile.com/uploads/scoop/main.cpp.txt
  // DWORD
  // LPHANDLE Handle,
  // DWORD    StackSize,
  // LPDWORD  ThreadId,
  // LPVOID   XapiThreadStartup, ?? often 0
  // LPVOID   StartAddress,
  // LPVOID   StartContext,
  // DWORD    CreationFlags // 0x80?

  // Inherit default stack size
  uint32_t actual_stack_size = stack_size;

  if (actual_stack_size == 0) {
    actual_stack_size = kernel_state()->GetExecutableModule()->stack_size();
  }

  // Stack must be aligned to 16kb pages
  actual_stack_size =
      std::max((uint32_t)0x4000, ((actual_stack_size + 0xFFF) & 0xFFFFF000));

  auto thread = object_ref<XThread>(
      new XThread(kernel_state(), actual_stack_size, xapi_thread_startup,
                  start_address, start_context, creation_flags, true));

  X_STATUS result = thread->Create();
  if (XFAILED(result)) {
    // Failed!
    XELOGE("Thread creation failed: {:08X}", result);
    return result;
  }

  if (XSUCCEEDED(result)) {
    if (handle_ptr) {
      if (creation_flags & 0x80) {
        *handle_ptr = thread->guest_object();
      } else {
        *handle_ptr = thread->handle();
      }
    }
    if (thread_id_ptr) {
      *thread_id_ptr = thread->thread_id();
    }
  }
  return result;
}

dword_result_t ExCreateThread_entry(lpdword_t handle_ptr, dword_t stack_size,
                                    lpdword_t thread_id_ptr,
                                    dword_t xapi_thread_startup,
                                    lpvoid_t start_address,
                                    lpvoid_t start_context,
                                    dword_t creation_flags) {
  return ExCreateThread(handle_ptr, stack_size, thread_id_ptr,
                        xapi_thread_startup, start_address, start_context,
                        creation_flags);
}
DECLARE_XBOXKRNL_EXPORT1(ExCreateThread, kThreading, kImplemented);

uint32_t ExTerminateThread(uint32_t exit_code) {
  XThread* thread = XThread::GetCurrentThread();

  // NOTE: this kills us right now. We won't return from it.
  return thread->Exit(exit_code);
}

dword_result_t ExTerminateThread_entry(dword_t exit_code) {
  return ExTerminateThread(exit_code);
}
DECLARE_XBOXKRNL_EXPORT1(ExTerminateThread, kThreading, kImplemented);

uint32_t NtResumeThread(uint32_t handle, uint32_t* suspend_count_ptr) {
  X_RESULT result = X_STATUS_INVALID_HANDLE;
  uint32_t suspend_count = 0;

  auto thread = kernel_state()->object_table()->LookupObject<XThread>(handle);

  if (thread) {
    if (thread->type() == XObject::Type::Thread) {
      result = thread->Resume(&suspend_count);
    } else {
      return X_STATUS_OBJECT_TYPE_MISMATCH;
    }
  } else {
    return X_STATUS_INVALID_HANDLE;
  }
  if (suspend_count_ptr) {
    *suspend_count_ptr = suspend_count;
  }

  return result;
}

dword_result_t NtResumeThread_entry(dword_t handle,
                                    lpdword_t suspend_count_ptr) {
  uint32_t suspend_count =
      suspend_count_ptr ? static_cast<uint32_t>(*suspend_count_ptr) : 0u;
  return NtResumeThread(handle, suspend_count_ptr ? &suspend_count : nullptr);
}
DECLARE_XBOXKRNL_EXPORT1(NtResumeThread, kThreading, kImplemented);

dword_result_t KeResumeThread_entry(pointer_t<X_KTHREAD> thread_ptr) {
  X_STATUS result = X_STATUS_SUCCESS;
  auto thread = XObject::GetNativeObject<XThread>(kernel_state(), thread_ptr);
  if (thread) {
    result = thread->Resume();
  } else {
    result = X_STATUS_INVALID_HANDLE;
  }

  return result;
}
DECLARE_XBOXKRNL_EXPORT1(KeResumeThread, kThreading, kImplemented);

dword_result_t NtSuspendThread_entry(dword_t handle,
                                     lpdword_t suspend_count_ptr,
                                     const ppc_context_t& context) {
  X_RESULT result = X_STATUS_SUCCESS;
  uint32_t suspend_count = 0;

  auto thread = kernel_state()->object_table()->LookupObject<XThread>(handle);
  if (thread) {
    if (thread->type() == XObject::Type::Thread) {
      auto current_pcr = context->TranslateVirtualGPR<X_KPCR*>(context->r[13]);

      if (current_pcr->current_thread == thread->guest_object() ||
          !thread->guest_object<X_KTHREAD>()->terminated) {
        result = thread->Suspend(&suspend_count);
      } else {
        return X_STATUS_THREAD_IS_TERMINATING;
      }
    } else {
      return X_STATUS_OBJECT_TYPE_MISMATCH;
    }
  } else {
    return X_STATUS_INVALID_HANDLE;
  }

  if (suspend_count_ptr) {
    *suspend_count_ptr = suspend_count;
  }

  return result;
}
DECLARE_XBOXKRNL_EXPORT1(NtSuspendThread, kThreading, kImplemented);

dword_result_t KeSuspendThread_entry(pointer_t<X_KTHREAD> kthread,
                                     const ppc_context_t& context) {
  auto thread =
      XObject::GetNativeObject<XThread>(context->kernel_state, kthread);
  uint32_t suspend_count_out = 0;

  if (thread) {
    suspend_count_out = thread->suspend_count();

    uint32_t discarded_new_suspend_count = 0;
    thread->Suspend(&discarded_new_suspend_count);
  }

  return suspend_count_out;
}
DECLARE_XBOXKRNL_EXPORT1(KeSuspendThread, kThreading, kImplemented);

void KeSetCurrentStackPointers_entry(lpvoid_t stack_ptr,
                                     pointer_t<X_KTHREAD> thread,
                                     lpvoid_t stack_alloc_base,
                                     lpvoid_t stack_base, lpvoid_t stack_limit,
                                     const ppc_context_t& context) {
  auto current_thread = XThread::GetCurrentThread();

  auto pcr = context->TranslateVirtualGPR<X_KPCR*>(context->r[13]);
  // also supposed to load msr mask, and the current msr with that, and store
  thread->stack_alloc_base = stack_alloc_base.value();
  thread->stack_base = stack_base.value();
  thread->stack_limit = stack_limit.value();
  pcr->stack_base_ptr = stack_base.guest_address();
  pcr->stack_end_ptr = stack_limit.guest_address();
  context->r[1] = stack_ptr.guest_address();

  // If a fiber is set, and the thread matches, reenter to avoid issues with
  // host stack overflowing.
  if (thread->fiber_ptr &&
      current_thread->guest_object() == thread.guest_address()) {
    context->processor->backend()->PrepareForReentry(context.value());
    current_thread->Reenter(static_cast<uint32_t>(context->lr));
  }
}
DECLARE_XBOXKRNL_EXPORT2(KeSetCurrentStackPointers, kThreading, kImplemented,
                         kHighFrequency);

dword_result_t KeSetAffinityThread_entry(lpvoid_t thread_ptr, dword_t affinity,
                                         lpdword_t previous_affinity_ptr) {
  // The Xbox 360, according to disassembly of KeSetAffinityThread, unlike
  // Windows NT, stores the previous affinity via the pointer provided as an
  // argument, not in the return value - the return value is used for the
  // result.
  if (!affinity) {
    return X_STATUS_INVALID_PARAMETER;
  }
  auto thread = XObject::GetNativeObject<XThread>(kernel_state(), thread_ptr);
  if (thread) {
    if (previous_affinity_ptr) {
      *previous_affinity_ptr = uint32_t(1) << thread->active_cpu();
    }
    thread->SetAffinity(affinity);
  }
  return X_STATUS_SUCCESS;
}
DECLARE_XBOXKRNL_EXPORT1(KeSetAffinityThread, kThreading, kImplemented);

dword_result_t KeQueryBasePriorityThread_entry(lpvoid_t thread_ptr) {
  int32_t priority = 0;

  auto thread = XObject::GetNativeObject<XThread>(kernel_state(), thread_ptr);
  if (thread) {
    priority = thread->QueryPriority();
  }

  return priority;
}
DECLARE_XBOXKRNL_EXPORT1(KeQueryBasePriorityThread, kThreading, kImplemented);

dword_result_t KeSetBasePriorityThread_entry(lpvoid_t thread_ptr,
                                             dword_t increment) {
  int32_t prev_priority = 0;
  auto thread = XObject::GetNativeObject<XThread>(kernel_state(), thread_ptr);

  if (thread) {
    prev_priority = thread->QueryPriority();
    thread->SetPriority(increment);
  }

  return prev_priority;
}
DECLARE_XBOXKRNL_EXPORT1(KeSetBasePriorityThread, kThreading, kImplemented);

dword_result_t KeSetDisableBoostThread_entry(lpvoid_t thread_ptr,
                                             dword_t disabled) {
  auto thread = XObject::GetNativeObject<XThread>(kernel_state(), thread_ptr);
  if (thread) {
    // Uhm?
  }

  return 0;
}
DECLARE_XBOXKRNL_EXPORT1(KeSetDisableBoostThread, kThreading, kImplemented);

dword_result_t KeGetCurrentProcessType_entry() {
  return kernel_state()->process_type();
}
DECLARE_XBOXKRNL_EXPORT2(KeGetCurrentProcessType, kThreading, kImplemented,
                         kHighFrequency);

void KeSetCurrentProcessType_entry(dword_t type) {
  // One of X_PROCTYPE_?

  assert_true(type <= 2);

  kernel_state()->set_process_type(type);
}
DECLARE_XBOXKRNL_EXPORT1(KeSetCurrentProcessType, kThreading, kImplemented);

dword_result_t KeQueryPerformanceFrequency_entry() {
  uint64_t result = Clock::guest_tick_frequency();
  return static_cast<uint32_t>(result);
}
DECLARE_XBOXKRNL_EXPORT2(KeQueryPerformanceFrequency, kThreading, kImplemented,
                         kHighFrequency);

uint32_t KeDelayExecutionThread(uint32_t processor_mode, uint32_t alertable,
                                uint64_t* interval_ptr) {
  XThread* thread = XThread::GetCurrentThread();
  X_STATUS result = thread->Delay(processor_mode, alertable, *interval_ptr);

  return result;
}

dword_result_t KeDelayExecutionThread_entry(dword_t processor_mode,
                                            dword_t alertable,
                                            lpqword_t interval_ptr) {
  uint64_t interval = interval_ptr ? static_cast<uint64_t>(*interval_ptr) : 0u;
  return KeDelayExecutionThread(processor_mode, alertable,
                                interval_ptr ? &interval : nullptr);
}
DECLARE_XBOXKRNL_EXPORT3(KeDelayExecutionThread, kThreading, kImplemented,
                         kBlocking, kHighFrequency);

dword_result_t NtYieldExecution_entry() {
  auto thread = XThread::GetCurrentThread();
  thread->Delay(0, 0, 0);
  return 0;
}
DECLARE_XBOXKRNL_EXPORT2(NtYieldExecution, kThreading, kImplemented,
                         kHighFrequency);

void KeQuerySystemTime_entry(lpqword_t time_ptr, const ppc_context_t& ctx) {
  if (time_ptr) {
    // update the timestamp bundle to the time we queried.
    // this is a race, but i don't of any sw that requires it, it just seems
    // like we ought to keep it consistent with ketimestampbundle in case
    // something uses this function, but also reads it directly
    uint32_t ts_bundle = ctx->kernel_state->GetKeTimestampBundle();
    uint64_t time = Clock::QueryGuestSystemTime();
    // todo: cmpxchg?
    xe::store_and_swap<uint64_t>(
        &ctx->TranslateVirtual<X_TIME_STAMP_BUNDLE*>(ts_bundle)->system_time,
        time);
    *time_ptr = time;
  }
}
DECLARE_XBOXKRNL_EXPORT1(KeQuerySystemTime, kThreading, kImplemented);

// https://msdn.microsoft.com/en-us/library/ms686801
dword_result_t KeTlsAlloc_entry() {
  uint32_t slot = kernel_state()->AllocateTLS();
  XThread::GetCurrentThread()->SetTLSValue(slot, 0);

  return slot;
}
DECLARE_XBOXKRNL_EXPORT1(KeTlsAlloc, kThreading, kImplemented);

// https://msdn.microsoft.com/en-us/library/ms686804
dword_result_t KeTlsFree_entry(dword_t tls_index) {
  if (tls_index == X_TLS_OUT_OF_INDEXES) {
    return 0;
  }

  kernel_state()->FreeTLS(tls_index);
  return 1;
}
DECLARE_XBOXKRNL_EXPORT1(KeTlsFree, kThreading, kImplemented);

// https://msdn.microsoft.com/en-us/library/ms686812
dword_result_t KeTlsGetValue_entry(dword_t tls_index) {
  // xboxkrnl doesn't actually have an error branch - it always succeeds, even
  // if it overflows the TLS.
  uint32_t value = 0;
  if (XThread::GetCurrentThread()->GetTLSValue(tls_index, &value)) {
    return value;
  }

  return 0;
}
DECLARE_XBOXKRNL_EXPORT2(KeTlsGetValue, kThreading, kImplemented,
                         kHighFrequency);

// https://msdn.microsoft.com/en-us/library/ms686818
dword_result_t KeTlsSetValue_entry(dword_t tls_index, dword_t tls_value) {
  // xboxkrnl doesn't actually have an error branch - it always succeeds, even
  // if it overflows the TLS.
  if (XThread::GetCurrentThread()->SetTLSValue(tls_index, tls_value)) {
    return 1;
  }

  return 0;
}
DECLARE_XBOXKRNL_EXPORT1(KeTlsSetValue, kThreading, kImplemented);

void KeInitializeEvent_entry(pointer_t<X_KEVENT> event_ptr, dword_t event_type,
                             dword_t initial_state) {
  event_ptr.Zero();
  event_ptr->header.type = event_type;
  event_ptr->header.signal_state = (uint32_t)initial_state;
  auto ev =
      XObject::GetNativeObject<XEvent>(kernel_state(), event_ptr, event_type);
  if (!ev) {
    assert_always();
    return;
  }
}
DECLARE_XBOXKRNL_EXPORT1(KeInitializeEvent, kThreading, kImplemented);

uint32_t xeKeSetEvent(X_KEVENT* event_ptr, uint32_t increment, uint32_t wait) {
  auto ev = XObject::GetNativeObject<XEvent>(kernel_state(), event_ptr);
  if (!ev) {
    assert_always();
    return 0;
  }

  return ev->Set(increment, !!wait);
}

dword_result_t KeSetEvent_entry(pointer_t<X_KEVENT> event_ptr,
                                dword_t increment, dword_t wait) {
  return xeKeSetEvent(event_ptr, increment, wait);
}
DECLARE_XBOXKRNL_EXPORT2(KeSetEvent, kThreading, kImplemented, kHighFrequency);

dword_result_t KePulseEvent_entry(pointer_t<X_KEVENT> event_ptr,
                                  dword_t increment, dword_t wait) {
  auto ev = XObject::GetNativeObject<XEvent>(kernel_state(), event_ptr);
  if (!ev) {
    assert_always();
    return 0;
  }

  return ev->Pulse(increment, !!wait);
}
DECLARE_XBOXKRNL_EXPORT2(KePulseEvent, kThreading, kImplemented,
                         kHighFrequency);

dword_result_t KeResetEvent_entry(pointer_t<X_KEVENT> event_ptr) {
  auto ev = XObject::GetNativeObject<XEvent>(kernel_state(), event_ptr);
  if (!ev) {
    assert_always();
    return 0;
  }

  return ev->Reset();
}
DECLARE_XBOXKRNL_EXPORT1(KeResetEvent, kThreading, kImplemented);

dword_result_t NtCreateEvent_entry(
    lpdword_t handle_ptr, pointer_t<X_OBJECT_ATTRIBUTES> obj_attributes_ptr,
    dword_t event_type, dword_t initial_state) {
  // Check for an existing timer with the same name.
  auto existing_object =
      LookupNamedObject<XEvent>(kernel_state(), obj_attributes_ptr);
  if (existing_object) {
    if (existing_object->type() == XObject::Type::Event) {
      if (handle_ptr) {
        existing_object->RetainHandle();
        *handle_ptr = existing_object->handle();
      }
      return X_STATUS_OBJECT_NAME_EXISTS;
    } else {
      return X_STATUS_INVALID_HANDLE;
    }
  }

  auto ev = object_ref<XEvent>(new XEvent(kernel_state()));
  ev->Initialize(!event_type, !!initial_state);

  // obj_attributes may have a name inside of it, if != NULL.
  if (obj_attributes_ptr) {
    ev->SetAttributes(obj_attributes_ptr);
  }

  if (handle_ptr) {
    *handle_ptr = ev->handle();
  }
  return X_STATUS_SUCCESS;
}
DECLARE_XBOXKRNL_EXPORT1(NtCreateEvent, kThreading, kImplemented);

uint32_t xeNtSetEvent(uint32_t handle, xe::be<uint32_t>* previous_state_ptr) {
  X_STATUS result = X_STATUS_SUCCESS;

  auto ev = kernel_state()->object_table()->LookupObject<XEvent>(handle);
  if (ev) {
    // d3 ros does this
    if (ev->type() != XObject::Type::Event) {
      return X_STATUS_OBJECT_TYPE_MISMATCH;
    }
    int32_t was_signalled = ev->Set(0, false);
    if (previous_state_ptr) {
      *previous_state_ptr = static_cast<uint32_t>(was_signalled);
    }
  } else {
    result = X_STATUS_INVALID_HANDLE;
  }

  return result;
}

dword_result_t NtSetEvent_entry(dword_t handle, lpdword_t previous_state_ptr) {
  return xeNtSetEvent(handle, previous_state_ptr);
}
DECLARE_XBOXKRNL_EXPORT2(NtSetEvent, kThreading, kImplemented, kHighFrequency);

dword_result_t NtPulseEvent_entry(dword_t handle,
                                  lpdword_t previous_state_ptr) {
  X_STATUS result = X_STATUS_SUCCESS;

  auto ev = kernel_state()->object_table()->LookupObject<XEvent>(handle);
  if (ev) {
    int32_t was_signalled = ev->Pulse(0, false);
    if (previous_state_ptr) {
      *previous_state_ptr = static_cast<uint32_t>(was_signalled);
    }
  } else {
    result = X_STATUS_INVALID_HANDLE;
  }

  return result;
}
DECLARE_XBOXKRNL_EXPORT2(NtPulseEvent, kThreading, kImplemented,
                         kHighFrequency);
dword_result_t NtQueryEvent_entry(dword_t handle, lpdword_t out_struc) {
  X_STATUS result = X_STATUS_SUCCESS;

  auto ev = kernel_state()->object_table()->LookupObject<XEvent>(handle);
  if (ev) {
    uint32_t type_tmp, state_tmp;

    ev->Query(&type_tmp, &state_tmp);

    out_struc[0] = type_tmp;
    out_struc[1] = state_tmp;
  } else {
    result = X_STATUS_INVALID_HANDLE;
  }

  return result;
}
DECLARE_XBOXKRNL_EXPORT2(NtQueryEvent, kThreading, kImplemented,
                         kHighFrequency);
uint32_t xeNtClearEvent(uint32_t handle) {
  X_STATUS result = X_STATUS_SUCCESS;

  auto ev = kernel_state()->object_table()->LookupObject<XEvent>(handle);
  if (ev) {
    ev->Reset();
  } else {
    result = X_STATUS_INVALID_HANDLE;
  }

  return result;
}

dword_result_t NtClearEvent_entry(dword_t handle) {
  return xeNtClearEvent(handle);
}
DECLARE_XBOXKRNL_EXPORT2(NtClearEvent, kThreading, kImplemented,
                         kHighFrequency);

// https://msdn.microsoft.com/en-us/library/windows/hardware/ff552150(v=vs.85).aspx
void KeInitializeSemaphore_entry(pointer_t<X_KSEMAPHORE> semaphore_ptr,
                                 dword_t count, dword_t limit) {
  semaphore_ptr->header.type = 5;  // SemaphoreObject
  semaphore_ptr->header.signal_state = (uint32_t)count;
  semaphore_ptr->limit = (uint32_t)limit;

  auto sem = XObject::GetNativeObject<XSemaphore>(kernel_state(), semaphore_ptr,
                                                  5 /* SemaphoreObject */);
  if (!sem) {
    assert_always();
    return;
  }
}
DECLARE_XBOXKRNL_EXPORT1(KeInitializeSemaphore, kThreading, kImplemented);

uint32_t xeKeReleaseSemaphore(X_KSEMAPHORE* semaphore_ptr, uint32_t increment,
                              uint32_t adjustment, uint32_t wait) {
  auto sem =
      XObject::GetNativeObject<XSemaphore>(kernel_state(), semaphore_ptr);
  if (!sem) {
    assert_always();
    return 0;
  }

  // TODO(benvanik): increment thread priority?
  // TODO(benvanik): wait?

  return sem->ReleaseSemaphore(adjustment);
}

dword_result_t KeReleaseSemaphore_entry(pointer_t<X_KSEMAPHORE> semaphore_ptr,
                                        dword_t increment, dword_t adjustment,
                                        dword_t wait) {
  return xeKeReleaseSemaphore(semaphore_ptr, increment, adjustment, wait);
}
DECLARE_XBOXKRNL_EXPORT1(KeReleaseSemaphore, kThreading, kImplemented);

dword_result_t NtCreateSemaphore_entry(lpdword_t handle_ptr,
                                       lpvoid_t obj_attributes_ptr,
                                       dword_t count, dword_t limit) {
  // Check for an existing semaphore with the same name.
  auto existing_object =
      LookupNamedObject<XSemaphore>(kernel_state(), obj_attributes_ptr);
  if (existing_object) {
    if (existing_object->type() == XObject::Type::Semaphore) {
      if (handle_ptr) {
        existing_object->RetainHandle();
        *handle_ptr = existing_object->handle();
      }
      return X_STATUS_OBJECT_NAME_EXISTS;
    } else {
      return X_STATUS_INVALID_HANDLE;
    }
  }

  auto sem = object_ref<XSemaphore>(new XSemaphore(kernel_state()));
  if (!sem->Initialize((int32_t)count, (int32_t)limit)) {
    if (handle_ptr) {
      *handle_ptr = 0;
    }
    sem->ReleaseHandle();
    return X_STATUS_INVALID_PARAMETER;
  }

  // obj_attributes may have a name inside of it, if != NULL.
  if (obj_attributes_ptr) {
    sem->SetAttributes(obj_attributes_ptr);
  }

  if (handle_ptr) {
    *handle_ptr = sem->handle();
  }

  return X_STATUS_SUCCESS;
}
DECLARE_XBOXKRNL_EXPORT1(NtCreateSemaphore, kThreading, kImplemented);

dword_result_t NtReleaseSemaphore_entry(dword_t sem_handle,
                                        dword_t release_count,
                                        lpdword_t previous_count_ptr) {
  X_STATUS result = X_STATUS_SUCCESS;
  int32_t previous_count = 0;

  auto sem =
      kernel_state()->object_table()->LookupObject<XSemaphore>(sem_handle);
  if (sem) {
    previous_count = sem->ReleaseSemaphore((int32_t)release_count);
  } else {
    result = X_STATUS_INVALID_HANDLE;
  }
  if (previous_count_ptr) {
    *previous_count_ptr = (uint32_t)previous_count;
  }

  return result;
}
DECLARE_XBOXKRNL_EXPORT2(NtReleaseSemaphore, kThreading, kImplemented,
                         kHighFrequency);

dword_result_t NtCreateMutant_entry(
    lpdword_t handle_out, pointer_t<X_OBJECT_ATTRIBUTES> obj_attributes,
    dword_t initial_owner) {
  // Check for an existing timer with the same name.
  auto existing_object = LookupNamedObject<XMutant>(
      kernel_state(), obj_attributes.guest_address());
  if (existing_object) {
    if (existing_object->type() == XObject::Type::Mutant) {
      if (handle_out) {
        existing_object->RetainHandle();
        *handle_out = existing_object->handle();
      }
      return X_STATUS_OBJECT_NAME_EXISTS;
    } else {
      return X_STATUS_INVALID_HANDLE;
    }
  }

  auto mutant = object_ref<XMutant>(new XMutant(kernel_state()));
  mutant->Initialize(initial_owner ? true : false);

  // obj_attributes may have a name inside of it, if != NULL.
  if (obj_attributes) {
    mutant->SetAttributes(obj_attributes);
  }

  if (handle_out) {
    *handle_out = mutant->handle();
  }

  return X_STATUS_SUCCESS;
}
DECLARE_XBOXKRNL_EXPORT1(NtCreateMutant, kThreading, kImplemented);

dword_result_t NtReleaseMutant_entry(dword_t mutant_handle, dword_t unknown) {
  // This doesn't seem to be supported.
  // int32_t previous_count_ptr = SHIM_GET_ARG_32(2);

  // Whatever arg 1 is all games seem to set it to 0, so whether it's
  // abandon or wait we just say false. Which is good, cause they are
  // both ignored.
  assert_zero(unknown);
  uint32_t priority_increment = 0;
  bool abandon = false;
  bool wait = false;

  X_STATUS result = X_STATUS_SUCCESS;

  auto mutant =
      kernel_state()->object_table()->LookupObject<XMutant>(mutant_handle);
  if (mutant) {
    mutant->ReleaseMutant(priority_increment, abandon, wait);
  } else {
    result = X_STATUS_INVALID_HANDLE;
  }

  return result;
}
DECLARE_XBOXKRNL_EXPORT1(NtReleaseMutant, kThreading, kImplemented);

dword_result_t NtCreateTimer_entry(lpdword_t handle_ptr,
                                   lpvoid_t obj_attributes_ptr,
                                   dword_t timer_type) {
  // timer_type = NotificationTimer (0) or SynchronizationTimer (1)

  // Check for an existing timer with the same name.
  auto existing_object =
      LookupNamedObject<XTimer>(kernel_state(), obj_attributes_ptr);
  if (existing_object) {
    if (existing_object->type() == XObject::Type::Timer) {
      if (handle_ptr) {
        existing_object->RetainHandle();
        *handle_ptr = existing_object->handle();
      }
      return X_STATUS_OBJECT_NAME_EXISTS;
    } else {
      return X_STATUS_INVALID_HANDLE;
    }
  }

  auto timer = object_ref<XTimer>(new XTimer(kernel_state()));
  timer->Initialize(timer_type);

  // obj_attributes may have a name inside of it, if != NULL.
  if (obj_attributes_ptr) {
    timer->SetAttributes(obj_attributes_ptr);
  }

  if (handle_ptr) {
    *handle_ptr = timer->handle();
  }

  return X_STATUS_SUCCESS;
}
DECLARE_XBOXKRNL_EXPORT1(NtCreateTimer, kThreading, kImplemented);

dword_result_t NtSetTimerEx_entry(dword_t timer_handle, lpqword_t due_time_ptr,
                                  lpvoid_t routine_ptr /*PTIMERAPCROUTINE*/,
                                  dword_t unk_one, lpvoid_t routine_arg,
                                  dword_t resume, dword_t period_ms,
                                  dword_t unk_zero) {
  assert_true(unk_one == 1);
  assert_true(unk_zero == 0);

  uint64_t due_time = *due_time_ptr;

  X_STATUS result = X_STATUS_SUCCESS;

  auto timer =
      kernel_state()->object_table()->LookupObject<XTimer>(timer_handle);
  if (timer) {
    result =
        timer->SetTimer(due_time, period_ms, routine_ptr.guest_address(),
                        routine_arg.guest_address(), resume ? true : false);
  } else {
    result = X_STATUS_INVALID_HANDLE;
  }

  return result;
}
DECLARE_XBOXKRNL_EXPORT1(NtSetTimerEx, kThreading, kImplemented);

dword_result_t NtCancelTimer_entry(dword_t timer_handle,
                                   lpdword_t current_state_ptr) {
  X_STATUS result = X_STATUS_SUCCESS;

  auto timer =
      kernel_state()->object_table()->LookupObject<XTimer>(timer_handle);
  if (timer) {
    result = timer->Cancel();
  } else {
    result = X_STATUS_INVALID_HANDLE;
  }
  if (current_state_ptr) {
    *current_state_ptr = 0;
  }

  return result;
}
DECLARE_XBOXKRNL_EXPORT1(NtCancelTimer, kThreading, kImplemented);

uint32_t xeKeWaitForSingleObject(void* object_ptr, uint32_t wait_reason,
                                 uint32_t processor_mode, uint32_t alertable,
                                 uint64_t* timeout_ptr) {
  auto object = XObject::GetNativeObject<XObject>(kernel_state(), object_ptr);

  if (!object) {
    // The only kind-of failure code (though this should never happen)
    assert_always();
    return X_STATUS_ABANDONED_WAIT_0;
  }

  X_STATUS result =
      object->Wait(wait_reason, processor_mode, alertable, timeout_ptr);

  return result;
}

dword_result_t KeWaitForSingleObject_entry(lpvoid_t object_ptr,
                                           dword_t wait_reason,
                                           dword_t processor_mode,
                                           dword_t alertable,
                                           lpqword_t timeout_ptr) {
  uint64_t timeout = timeout_ptr ? static_cast<uint64_t>(*timeout_ptr) : 0u;
  return xeKeWaitForSingleObject(object_ptr, wait_reason, processor_mode,
                                 alertable, timeout_ptr ? &timeout : nullptr);
}
DECLARE_XBOXKRNL_EXPORT3(KeWaitForSingleObject, kThreading, kImplemented,
                         kBlocking, kHighFrequency);

uint32_t NtWaitForSingleObjectEx(uint32_t object_handle, uint32_t wait_mode,
                                 uint32_t alertable, uint64_t* timeout_ptr) {
  X_STATUS result = X_STATUS_SUCCESS;

  auto object =
      kernel_state()->object_table()->LookupObject<XObject>(object_handle);
  if (object) {
    uint64_t timeout = timeout_ptr ? static_cast<uint64_t>(*timeout_ptr) : 0u;
    result =
        object->Wait(3, wait_mode, alertable, timeout_ptr ? &timeout : nullptr);
  } else {
    result = X_STATUS_INVALID_HANDLE;
  }

  return result;
}

dword_result_t NtWaitForSingleObjectEx_entry(dword_t object_handle,
                                             dword_t wait_mode,
                                             dword_t alertable,
                                             lpqword_t timeout_ptr) {
  uint64_t timeout = timeout_ptr ? static_cast<uint64_t>(*timeout_ptr) : 0u;
  return NtWaitForSingleObjectEx(object_handle, wait_mode, alertable,
                                 timeout_ptr ? &timeout : nullptr);
}
DECLARE_XBOXKRNL_EXPORT3(NtWaitForSingleObjectEx, kThreading, kImplemented,
                         kBlocking, kHighFrequency);

dword_result_t KeWaitForMultipleObjects_entry(
    dword_t count, lpdword_t objects_ptr, dword_t wait_type,
    dword_t wait_reason, dword_t processor_mode, dword_t alertable,
    lpqword_t timeout_ptr, lpvoid_t wait_block_array_ptr) {
  assert_true(wait_type <= 1);

  assert_true(count <= 64);
  object_ref<XObject> objects[64];
  {
    auto crit = global_critical_region::AcquireDirect();
    for (uint32_t n = 0; n < count; n++) {
      auto object_ptr = kernel_memory()->TranslateVirtual(objects_ptr[n]);
      auto object_ref = XObject::GetNativeObject<XObject>(kernel_state(),
                                                          object_ptr, -1, true);
      if (!object_ref) {
        return X_STATUS_INVALID_PARAMETER;
      }

      objects[n] = std::move(object_ref);
    }
  }
  uint64_t timeout = timeout_ptr ? static_cast<uint64_t>(*timeout_ptr) : 0u;
  return XObject::WaitMultiple(
      uint32_t(count), reinterpret_cast<XObject**>(&objects[0]), wait_type,
      wait_reason, processor_mode, alertable, timeout_ptr ? &timeout : nullptr);
}
DECLARE_XBOXKRNL_EXPORT3(KeWaitForMultipleObjects, kThreading, kImplemented,
                         kBlocking, kHighFrequency);

uint32_t xeNtWaitForMultipleObjectsEx(uint32_t count, xe::be<uint32_t>* handles,
                                      uint32_t wait_type, uint32_t wait_mode,
                                      uint32_t alertable,
                                      uint64_t* timeout_ptr) {
  assert_true(wait_type <= 1);

  assert_true(count <= 64);
  object_ref<XObject> objects[64];

  /*
        Reserving to squash the constant reallocations, in a benchmark of one
     particular game over a period of five minutes roughly 11% of CPU time was
     spent inside a helper function to Windows' heap allocation function. 7% of
     that time was traced back to here

         edit: actually switched to fixed size array, as there can never be more
     than 64 events specified
  */
  {
    auto crit = global_critical_region::AcquireDirect();
    for (uint32_t n = 0; n < count; n++) {
      uint32_t object_handle = handles[n];
      auto object = kernel_state()->object_table()->LookupObject<XObject>(
          object_handle, true);
      if (!object) {
        return X_STATUS_INVALID_PARAMETER;
      }
      objects[n] = std::move(object);
    }
  }

  return XObject::WaitMultiple(count, reinterpret_cast<XObject**>(&objects[0]),
                               wait_type, 6, wait_mode, alertable, timeout_ptr);
}

dword_result_t NtWaitForMultipleObjectsEx_entry(
    dword_t count, lpdword_t handles, dword_t wait_type, dword_t wait_mode,
    dword_t alertable, lpqword_t timeout_ptr) {
  uint64_t timeout = timeout_ptr ? static_cast<uint64_t>(*timeout_ptr) : 0u;
  if (!count || count > 64 || (wait_type != 1 && wait_type)) {
    return X_STATUS_INVALID_PARAMETER;
  }
  return xeNtWaitForMultipleObjectsEx(count, handles, wait_type, wait_mode,
                                      alertable,
                                      timeout_ptr ? &timeout : nullptr);
}
DECLARE_XBOXKRNL_EXPORT3(NtWaitForMultipleObjectsEx, kThreading, kImplemented,
                         kBlocking, kHighFrequency);

dword_result_t NtSignalAndWaitForSingleObjectEx_entry(dword_t signal_handle,
                                                      dword_t wait_handle,
                                                      dword_t alertable,
                                                      dword_t r6,
                                                      lpqword_t timeout_ptr) {
  X_STATUS result = X_STATUS_SUCCESS;
  // pre-lock for these two handle lookups
  global_critical_region::mutex().lock();

  auto signal_object = kernel_state()->object_table()->LookupObject<XObject>(
      signal_handle, true);
  auto wait_object =
      kernel_state()->object_table()->LookupObject<XObject>(wait_handle, true);
  global_critical_region::mutex().unlock();
  if (signal_object && wait_object) {
    uint64_t timeout = timeout_ptr ? static_cast<uint64_t>(*timeout_ptr) : 0u;
    result =
        XObject::SignalAndWait(signal_object.get(), wait_object.get(), 3, 1,
                               alertable, timeout_ptr ? &timeout : nullptr);
  } else {
    result = X_STATUS_INVALID_HANDLE;
  }

  return result;
}
DECLARE_XBOXKRNL_EXPORT3(NtSignalAndWaitForSingleObjectEx, kThreading,
                         kImplemented, kBlocking, kHighFrequency);

static void PrefetchForCAS(const void* value) { swcache::PrefetchW(value); }

uint32_t xeKeKfAcquireSpinLock(uint32_t* lock, uint64_t r13 = 1) {
  // XELOGD(
  //     "KfAcquireSpinLock({:08X})",
  //     lock_ptr);
  PrefetchForCAS(lock);
  assert_true(*lock != static_cast<uint32_t>(r13));
  // Lock.
  while (!xe::atomic_cas(0, xe::byte_swap(static_cast<uint32_t>(r13)), lock)) {
    // Spin!
    // TODO(benvanik): error on deadlock?
    xe::threading::MaybeYield();
  }

  // Raise IRQL to DISPATCH.
  XThread* thread = XThread::GetCurrentThread();
  auto old_irql = thread->RaiseIrql(2);

  return old_irql;
}

dword_result_t KfAcquireSpinLock_entry(lpdword_t lock_ptr,
                                       const ppc_context_t& ppc_context) {
  auto lock = reinterpret_cast<uint32_t*>(lock_ptr.host_address());
  return xeKeKfAcquireSpinLock(lock, ppc_context->r[13]);
}
DECLARE_XBOXKRNL_EXPORT3(KfAcquireSpinLock, kThreading, kImplemented, kBlocking,
                         kHighFrequency);

void xeKeKfReleaseSpinLock(uint32_t* lock, dword_t old_irql) {
  // Unlock.
  *lock = 0;
  if (old_irql >= 2) {
    return;
  }
  // Restore IRQL.
  XThread* thread = XThread::GetCurrentThread();
  thread->LowerIrql(old_irql);
}

void KfReleaseSpinLock_entry(lpdword_t lock_ptr, dword_t old_irql,
                             const ppc_context_t& ppc_ctx) {
  assert_true(*lock_ptr == static_cast<uint32_t>(ppc_ctx->r[13]));

  *lock_ptr = 0;
  if (old_irql >= 2) {
    return;
  }
  // Restore IRQL.
  XThread* thread = XThread::GetCurrentThread();
  thread->LowerIrql(old_irql);
}
DECLARE_XBOXKRNL_EXPORT2(KfReleaseSpinLock, kThreading, kImplemented,
                         kHighFrequency);
// todo: this is not accurate
void KeAcquireSpinLockAtRaisedIrql_entry(lpdword_t lock_ptr,
                                         const ppc_context_t& ppc_ctx) {
  // Lock.
  auto lock = reinterpret_cast<uint32_t*>(lock_ptr.host_address());
  // must not be our own thread
  assert_true(*lock_ptr != static_cast<uint32_t>(ppc_ctx->r[13]));

  PrefetchForCAS(lock);
  while (!xe::atomic_cas(
      0, xe::byte_swap(static_cast<uint32_t>(ppc_ctx->r[13])), lock)) {
#if XE_ARCH_AMD64 == 1
    // todo: this is just a nop if they don't have SMT, which is not great
    // either...

    _mm_pause();
#endif
    // Spin!
    // TODO(benvanik): error on deadlock?
  }
}
DECLARE_XBOXKRNL_EXPORT3(KeAcquireSpinLockAtRaisedIrql, kThreading,
                         kImplemented, kBlocking, kHighFrequency);

dword_result_t KeTryToAcquireSpinLockAtRaisedIrql_entry(
    lpdword_t lock_ptr, const ppc_context_t& ppc_ctx) {
  // Lock.
  auto lock = reinterpret_cast<uint32_t*>(lock_ptr.host_address());
  assert_true(*lock_ptr != static_cast<uint32_t>(ppc_ctx->r[13]));
  PrefetchForCAS(lock);
  if (!xe::atomic_cas(0, xe::byte_swap(static_cast<uint32_t>(ppc_ctx->r[13])),
                      lock)) {
    return 0;
  }
  return 1;
}
DECLARE_XBOXKRNL_EXPORT4(KeTryToAcquireSpinLockAtRaisedIrql, kThreading,
                         kImplemented, kBlocking, kHighFrequency, kSketchy);

void KeReleaseSpinLockFromRaisedIrql_entry(lpdword_t lock_ptr,
                                           const ppc_context_t& ppc_ctx) {
  // Unlock.
  assert_true(*lock_ptr == static_cast<uint32_t>(ppc_ctx->r[13]));
  *lock_ptr = 0;
}
DECLARE_XBOXKRNL_EXPORT2(KeReleaseSpinLockFromRaisedIrql, kThreading,
                         kImplemented, kHighFrequency);

void KeEnterCriticalRegion_entry() {
  XThread::GetCurrentThread()->EnterCriticalRegion();
}
DECLARE_XBOXKRNL_EXPORT2(KeEnterCriticalRegion, kThreading, kImplemented,
                         kHighFrequency);

void KeLeaveCriticalRegion_entry() {
  XThread::GetCurrentThread()->LeaveCriticalRegion();
}
DECLARE_XBOXKRNL_EXPORT2(KeLeaveCriticalRegion, kThreading, kImplemented,
                         kHighFrequency);

dword_result_t KeRaiseIrqlToDpcLevel_entry(const ppc_context_t& ctx) {
  auto pcr = ctx.GetPCR();
  uint32_t old_irql = pcr->current_irql;

  if (old_irql > 2) {
    XELOGE("KeRaiseIrqlToDpcLevel - old_irql > 2");
  }

  pcr->current_irql = 2;

  return old_irql;
}
DECLARE_XBOXKRNL_EXPORT2(KeRaiseIrqlToDpcLevel, kThreading, kImplemented,
                         kHighFrequency);

// irql is supposed to be per thread afaik...
void KfLowerIrql_entry(dword_t new_irql, const ppc_context_t& ctx) {
  X_KPCR* kpcr = ctx.GetPCR();

  if (new_irql > kpcr->current_irql) {
    XELOGE("KfLowerIrql : new_irql > kpcr->current_irql!");
  }
  kpcr->current_irql = new_irql;
  if (new_irql < 2) {
    {
      // this actually calls a function that eventually calls checkapcs.
      // the called function does a ton of other stuff including changing the
      // irql and interrupt_related
      ctx.CurrentXThread()->CheckApcs();
    }
  }
}
DECLARE_XBOXKRNL_EXPORT2(KfLowerIrql, kThreading, kImplemented, kHighFrequency);

// used by aurora's nova plugin
// like the other irql related functions, writes to an unknown mmio range (
// 0x7FFF ). The range is indexed by the low 16 bits of the KPCR's pointer (so
// r13)
dword_result_t KfRaiseIrql_entry(dword_t new_irql, const ppc_context_t& ctx) {
  X_KPCR* v1 = ctx.GetPCR();

  uint32_t old_irql = v1->current_irql;
  v1->current_irql = new_irql;

  if (old_irql > (unsigned int)new_irql) {
    XELOGE("KfRaiseIrql - old_irql > new_irql!");
  }
  return old_irql;
}

DECLARE_XBOXKRNL_EXPORT2(KfRaiseIrql, kThreading, kImplemented, kHighFrequency);

void NtQueueApcThread_entry(dword_t thread_handle, lpvoid_t apc_routine,
                            lpvoid_t apc_routine_context, lpvoid_t arg1,
                            lpvoid_t arg2) {
  auto thread =
      kernel_state()->object_table()->LookupObject<XThread>(thread_handle);

  if (!thread) {
    XELOGE("NtQueueApcThread: Incorrect thread handle! Might cause crash");
    return;
  }

  if (!apc_routine) {
    XELOGE("NtQueueApcThread: Incorrect apc routine! Might cause crash");
    return;
  }

  thread->EnqueueApc(apc_routine, apc_routine_context, arg1, arg2);
}
DECLARE_XBOXKRNL_EXPORT1(NtQueueApcThread, kThreading, kImplemented);

void KeInitializeApc_entry(pointer_t<XAPC> apc, lpvoid_t thread_ptr,
                           lpvoid_t kernel_routine, lpvoid_t rundown_routine,
                           lpvoid_t normal_routine, dword_t processor_mode,
                           lpvoid_t normal_context) {
  apc->Initialize();
  apc->processor_mode = processor_mode;
  apc->thread_ptr = thread_ptr.guest_address();
  apc->kernel_routine = kernel_routine.guest_address();
  apc->rundown_routine = rundown_routine.guest_address();
  apc->normal_routine = normal_routine.guest_address();
  apc->normal_context =
      normal_routine.guest_address() ? normal_context.guest_address() : 0;
}
DECLARE_XBOXKRNL_EXPORT1(KeInitializeApc, kThreading, kImplemented);

dword_result_t KeInsertQueueApc_entry(pointer_t<XAPC> apc, lpvoid_t arg1,
                                      lpvoid_t arg2,
                                      dword_t priority_increment) {
  auto thread = XObject::GetNativeObject<XThread>(
      kernel_state(),
      kernel_state()->memory()->TranslateVirtual(apc->thread_ptr));
  if (!thread) {
    return 0;
  }

  // Lock thread.
  thread->LockApc();

  // Fail if already inserted.
  if (apc->enqueued) {
    thread->UnlockApc(false);
    return 0;
  }

  // Prep APC.
  apc->arg1 = arg1.guest_address();
  apc->arg2 = arg2.guest_address();
  apc->enqueued = 1;

  auto apc_list = thread->apc_list();

  uint32_t list_entry_ptr = apc.guest_address() + 8;
  apc_list->Insert(list_entry_ptr);

  // Unlock thread.
  thread->UnlockApc(true);

  return 1;
}
DECLARE_XBOXKRNL_EXPORT1(KeInsertQueueApc, kThreading, kImplemented);

dword_result_t KeRemoveQueueApc_entry(pointer_t<XAPC> apc) {
  bool result = false;

  auto thread = XObject::GetNativeObject<XThread>(
      kernel_state(),
      kernel_state()->memory()->TranslateVirtual(apc->thread_ptr));
  if (!thread) {
    return 0;
  }

  thread->LockApc();

  if (!apc->enqueued) {
    thread->UnlockApc(false);
    return 0;
  }

  auto apc_list = thread->apc_list();
  uint32_t list_entry_ptr = apc.guest_address() + 8;
  if (apc_list->IsQueued(list_entry_ptr)) {
    apc_list->Remove(list_entry_ptr);
    result = true;
  }

  thread->UnlockApc(true);

  return result ? 1 : 0;
}
DECLARE_XBOXKRNL_EXPORT1(KeRemoveQueueApc, kThreading, kImplemented);

dword_result_t KiApcNormalRoutineNop_entry(dword_t unk0 /* output? */,
                                           dword_t unk1 /* 0x13 */) {
  return 0;
}
DECLARE_XBOXKRNL_EXPORT1(KiApcNormalRoutineNop, kThreading, kStub);

typedef struct {
  xe::be<uint32_t> unknown;
  xe::be<uint32_t> flink;
  xe::be<uint32_t> blink;
  xe::be<uint32_t> routine;
  xe::be<uint32_t> context;
  xe::be<uint32_t> arg1;
  xe::be<uint32_t> arg2;
} XDPC;

void KeInitializeDpc_entry(pointer_t<XDPC> dpc, lpvoid_t routine,
                           lpvoid_t context) {
  // KDPC (maybe) 0x18 bytes?
  uint32_t type = 19;  // DpcObject
  uint32_t importance = 0;
  uint32_t number = 0;  // ?
  dpc->unknown = (type << 24) | (importance << 16) | (number);
  dpc->flink = 0;
  dpc->blink = 0;
  dpc->routine = routine.guest_address();
  dpc->context = context.guest_address();
  dpc->arg1 = 0;
  dpc->arg2 = 0;
}
DECLARE_XBOXKRNL_EXPORT2(KeInitializeDpc, kThreading, kImplemented, kSketchy);

dword_result_t KeInsertQueueDpc_entry(pointer_t<XDPC> dpc, dword_t arg1,
                                      dword_t arg2) {
  assert_always("DPC does not dispatch yet; going to hang!");

  uint32_t list_entry_ptr = dpc.guest_address() + 4;

  // Lock dispatcher.
  auto global_lock = xe::global_critical_region::AcquireDirect();
  auto dpc_list = kernel_state()->dpc_list();

  // If already in a queue, abort.
  if (dpc_list->IsQueued(list_entry_ptr)) {
    return 0;
  }

  // Prep DPC.
  dpc->arg1 = (uint32_t)arg1;
  dpc->arg2 = (uint32_t)arg2;

  dpc_list->Insert(list_entry_ptr);

  return 1;
}
DECLARE_XBOXKRNL_EXPORT2(KeInsertQueueDpc, kThreading, kStub, kSketchy);

dword_result_t KeRemoveQueueDpc_entry(pointer_t<XDPC> dpc) {
  bool result = false;

  uint32_t list_entry_ptr = dpc.guest_address() + 4;

  auto global_lock = xe::global_critical_region::AcquireDirect();
  auto dpc_list = kernel_state()->dpc_list();
  if (dpc_list->IsQueued(list_entry_ptr)) {
    dpc_list->Remove(list_entry_ptr);
    result = true;
  }

  return result ? 1 : 0;
}
DECLARE_XBOXKRNL_EXPORT1(KeRemoveQueueDpc, kThreading, kImplemented);

// https://github.com/Cxbx-Reloaded/Cxbx-Reloaded/blob/51e4dfcaacfdbd1a9692272931a436371492f72d/import/OpenXDK/include/xboxkrnl/xboxkrnl.h#L1372
struct X_ERWLOCK {
  be<int32_t> lock_count;              // 0x0
  be<uint32_t> writers_waiting_count;  // 0x4
  be<uint32_t> readers_waiting_count;  // 0x8
  be<uint32_t> readers_entry_count;    // 0xC
  X_KEVENT writer_event;               // 0x10
  X_KSEMAPHORE reader_semaphore;       // 0x20
  uint32_t spin_lock;                  // 0x34
};
static_assert_size(X_ERWLOCK, 0x38);

void ExInitializeReadWriteLock_entry(pointer_t<X_ERWLOCK> lock_ptr) {
  lock_ptr->lock_count = -1;
  lock_ptr->writers_waiting_count = 0;
  lock_ptr->readers_waiting_count = 0;
  lock_ptr->readers_entry_count = 0;
  KeInitializeEvent_entry(&lock_ptr->writer_event, 1, 0);
  KeInitializeSemaphore_entry(&lock_ptr->reader_semaphore, 0, 0x7FFFFFFF);
  lock_ptr->spin_lock = 0;
}
DECLARE_XBOXKRNL_EXPORT1(ExInitializeReadWriteLock, kThreading, kImplemented);

void ExAcquireReadWriteLockExclusive_entry(pointer_t<X_ERWLOCK> lock_ptr,
                                           const ppc_context_t& ppc_context) {
  auto old_irql =
      xeKeKfAcquireSpinLock(&lock_ptr->spin_lock, ppc_context->r[13]);

  int32_t lock_count = ++lock_ptr->lock_count;
  if (!lock_count) {
    xeKeKfReleaseSpinLock(&lock_ptr->spin_lock, old_irql);
    return;
  }

  lock_ptr->writers_waiting_count++;

  xeKeKfReleaseSpinLock(&lock_ptr->spin_lock, old_irql);
  xeKeWaitForSingleObject(&lock_ptr->writer_event, 7, 0, 0, nullptr);
}
DECLARE_XBOXKRNL_EXPORT2(ExAcquireReadWriteLockExclusive, kThreading,
                         kImplemented, kBlocking);

dword_result_t ExTryToAcquireReadWriteLockExclusive_entry(
    pointer_t<X_ERWLOCK> lock_ptr, const ppc_context_t& ppc_context) {
  auto old_irql =
      xeKeKfAcquireSpinLock(&lock_ptr->spin_lock, ppc_context->r[13]);

  uint32_t result;
  if (lock_ptr->lock_count < 0) {
    lock_ptr->lock_count = 0;
    result = 1;
  } else {
    result = 0;
  }

  xeKeKfReleaseSpinLock(&lock_ptr->spin_lock, old_irql);
  return result;
}
DECLARE_XBOXKRNL_EXPORT1(ExTryToAcquireReadWriteLockExclusive, kThreading,
                         kImplemented);

void ExAcquireReadWriteLockShared_entry(pointer_t<X_ERWLOCK> lock_ptr,
                                        const ppc_context_t& ppc_context) {
  auto old_irql =
      xeKeKfAcquireSpinLock(&lock_ptr->spin_lock, ppc_context->r[13]);

  int32_t lock_count = ++lock_ptr->lock_count;
  if (!lock_count ||
      (lock_ptr->readers_entry_count && !lock_ptr->writers_waiting_count)) {
    lock_ptr->readers_entry_count++;
    xeKeKfReleaseSpinLock(&lock_ptr->spin_lock, old_irql);
    return;
  }

  lock_ptr->readers_waiting_count++;

  xeKeKfReleaseSpinLock(&lock_ptr->spin_lock, old_irql);
  xeKeWaitForSingleObject(&lock_ptr->reader_semaphore, 7, 0, 0, nullptr);
}
DECLARE_XBOXKRNL_EXPORT2(ExAcquireReadWriteLockShared, kThreading, kImplemented,
                         kBlocking);

dword_result_t ExTryToAcquireReadWriteLockShared_entry(
    pointer_t<X_ERWLOCK> lock_ptr, const ppc_context_t& ppc_context) {
  auto old_irql =
      xeKeKfAcquireSpinLock(&lock_ptr->spin_lock, ppc_context->r[13]);

  uint32_t result;
  if (lock_ptr->lock_count < 0 ||
      (lock_ptr->readers_entry_count && !lock_ptr->writers_waiting_count)) {
    lock_ptr->lock_count++;
    lock_ptr->readers_entry_count++;
    result = 1;
  } else {
    result = 0;
  }

  xeKeKfReleaseSpinLock(&lock_ptr->spin_lock, old_irql);
  return result;
}
DECLARE_XBOXKRNL_EXPORT1(ExTryToAcquireReadWriteLockShared, kThreading,
                         kImplemented);

void ExReleaseReadWriteLock_entry(pointer_t<X_ERWLOCK> lock_ptr,
                                  const ppc_context_t& ppc_context) {
  auto old_irql =
      xeKeKfAcquireSpinLock(&lock_ptr->spin_lock, ppc_context->r[13]);

  int32_t lock_count = --lock_ptr->lock_count;

  if (lock_count < 0) {
    lock_ptr->readers_entry_count = 0;
    xeKeKfReleaseSpinLock(&lock_ptr->spin_lock, old_irql);
    return;
  }

  if (!lock_ptr->readers_entry_count) {
    auto readers_waiting_count = lock_ptr->readers_waiting_count;
    if (readers_waiting_count) {
      lock_ptr->readers_waiting_count = 0;
      lock_ptr->readers_entry_count = readers_waiting_count;
      xeKeKfReleaseSpinLock(&lock_ptr->spin_lock, old_irql);
      xeKeReleaseSemaphore(&lock_ptr->reader_semaphore, 1,
                           readers_waiting_count, 0);
      return;
    }
  }

  auto readers_entry_count = --lock_ptr->readers_entry_count;
  if (readers_entry_count) {
    xeKeKfReleaseSpinLock(&lock_ptr->spin_lock, old_irql);
    return;
  }

  lock_ptr->writers_waiting_count--;
  xeKeKfReleaseSpinLock(&lock_ptr->spin_lock, old_irql);
  xeKeSetEvent(&lock_ptr->writer_event, 1, 0);
}
DECLARE_XBOXKRNL_EXPORT1(ExReleaseReadWriteLock, kThreading, kImplemented);

// NOTE: This function is very commonly inlined, and probably won't be called!
pointer_result_t InterlockedPushEntrySList_entry(
    pointer_t<X_SLIST_HEADER> plist_ptr, pointer_t<X_SINGLE_LIST_ENTRY> entry) {
  assert_not_null(plist_ptr);
  assert_not_null(entry);

  alignas(8) X_SLIST_HEADER old_hdr = *plist_ptr;
  alignas(8) X_SLIST_HEADER new_hdr = {{0}, 0, 0};
  uint32_t old_head = 0;
  do {
    old_hdr = *plist_ptr;
    new_hdr.depth = old_hdr.depth + 1;
    new_hdr.sequence = old_hdr.sequence + 1;

    old_head = old_hdr.next.next;
    entry->next = old_hdr.next.next;
    new_hdr.next.next = entry.guest_address();
  } while (
      !xe::atomic_cas(*(uint64_t*)(&old_hdr), *(uint64_t*)(&new_hdr),
                      reinterpret_cast<uint64_t*>(plist_ptr.host_address())));

  return old_head;
}
DECLARE_XBOXKRNL_EXPORT2(InterlockedPushEntrySList, kThreading, kImplemented,
                         kHighFrequency);

pointer_result_t InterlockedPopEntrySList_entry(
    pointer_t<X_SLIST_HEADER> plist_ptr) {
  assert_not_null(plist_ptr);

  uint32_t popped = 0;
  alignas(8) X_SLIST_HEADER old_hdr = {{0}, 0, 0};
  alignas(8) X_SLIST_HEADER new_hdr = {{0}, 0, 0};
  do {
    old_hdr = *plist_ptr;
    auto next = kernel_memory()->TranslateVirtual<X_SINGLE_LIST_ENTRY*>(
        old_hdr.next.next);
    if (!old_hdr.next.next) {
      return 0;
    }
    popped = old_hdr.next.next;

    new_hdr.depth = old_hdr.depth - 1;
    new_hdr.next.next = next->next;
    new_hdr.sequence = old_hdr.sequence;
  } while (
      !xe::atomic_cas(*(uint64_t*)(&old_hdr), *(uint64_t*)(&new_hdr),
                      reinterpret_cast<uint64_t*>(plist_ptr.host_address())));

  return popped;
}
DECLARE_XBOXKRNL_EXPORT2(InterlockedPopEntrySList, kThreading, kImplemented,
                         kHighFrequency);

pointer_result_t InterlockedFlushSList_entry(
    pointer_t<X_SLIST_HEADER> plist_ptr) {
  assert_not_null(plist_ptr);

  alignas(8) X_SLIST_HEADER old_hdr = *plist_ptr;
  alignas(8) X_SLIST_HEADER new_hdr = {{0}, 0, 0};
  uint32_t first = 0;
  do {
    old_hdr = *plist_ptr;
    first = old_hdr.next.next;
    new_hdr.next.next = 0;
    new_hdr.depth = 0;
    new_hdr.sequence = 0;
  } while (
      !xe::atomic_cas(*(uint64_t*)(&old_hdr), *(uint64_t*)(&new_hdr),
                      reinterpret_cast<uint64_t*>(plist_ptr.host_address())));

  return first;
}
DECLARE_XBOXKRNL_EXPORT1(InterlockedFlushSList, kThreading, kImplemented);

}  // namespace xboxkrnl
}  // namespace kernel
}  // namespace xe

DECLARE_XBOXKRNL_EMPTY_REGISTER_EXPORTS(Threading);