Function ThreadInit

Source/Windows/ARM64EC/Module.cpp:946–1010

void BTCpu64NotifyReadFile(HANDLE Handle, void* Address, SIZE_T Size, BOOL After, NTSTATUS Status) {}

NTSTATUS ThreadInit() {
  std::scoped_lock Lock(ThreadCreationMutex);
  FEX::Windows::InitCRTThread();
  static constexpr size_t EmulatorStackSize = 0x40000;
  const uint64_t EmulatorStack = reinterpret_cast<uint64_t>(::VirtualAlloc(nullptr, EmulatorStackSize, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE));
  GetCPUArea().EmulatorStackLimit() = EmulatorStack;
  GetCPUArea().EmulatorStackBase() = EmulatorStack + EmulatorStackSize;

  const auto CPUArea = GetCPUArea();

  auto* Thread = CTX->CreateThread(0, 0);

  // Default segment setup.
  auto Frame = Thread->CurrentFrame;
  auto NewSegments = new FEXCore::Core::CPUState::gdt_segment[32];

  // Setup initial code-segment GDT
  auto& GDT = NewSegments[FEXCore::Core::CPUState::DEFAULT_USER_CS];
  FEXCore::Core::CPUState::SetGDTBase(&GDT, 0);
  FEXCore::Core::CPUState::SetGDTLimit(&GDT, 0xF'FFFFU);
  GDT.L = 1; // L = Long Mode = 64-bit
  GDT.D = 0; // D = Default Operand SIze = Reserved

  Frame->State.segment_arrays[FEXCore::Core::CPUState::SEGMENT_ARRAY_INDEX_GDT] = &NewSegments[0];
  // TODO: LDTs are currently unsupported, mirror them to GDT.
  Frame->State.segment_arrays[FEXCore::Core::CPUState::SEGMENT_ARRAY_INDEX_LDT] = &NewSegments[0];

  Frame->State.cs_idx = FEXCore::Core::CPUState::DEFAULT_USER_CS << 3;
  Frame->State.cs_cached = FEXCore::Core::CPUState::CalculateGDTBase(GDT);

  FEX::Windows::CallRetStack::InitializeThread(Thread);
  Thread->CurrentFrame->Pointers.Common.ExitFunctionEC = reinterpret_cast<uintptr_t>(&ExitFunctionEC);
  CPUArea.StateFrame() = Thread->CurrentFrame;

  uint64_t EnterEC = Thread->CurrentFrame->Pointers.Common.DispatcherLoopTopEnterEC;
  CPUArea.DispatcherLoopTopEnterEC() = EnterEC;

  uint64_t EnterECFillSRA = Thread->CurrentFrame->Pointers.Common.DispatcherLoopTopEnterECFillSRA;
  CPUArea.DispatcherLoopTopEnterECFillSRA() = EnterECFillSRA;

  CPUArea.ContextAmd64() = {.ContextFlags = CONTEXT_CONTROL | CONTEXT_SEGMENTS | CONTEXT_INTEGER | CONTEXT_FLOATING_POINT,
                            .AMD64_SegCs = (FEXCore::Core::CPUState::DEFAULT_USER_CS << 3) | 3,
                            .AMD64_SegDs = 0x2b,
                            .AMD64_SegEs = 0x2b,
                            .AMD64_SegFs = 0x53,
                            .AMD64_SegGs = 0x2b,
                            .AMD64_SegSs = 0x2b,
                            .AMD64_EFlags = 0x202,
                            .AMD64_MxCsr = 0x1f80,
                            .AMD64_MxCsr_copy = 0x1f80,
                            .AMD64_ControlWord = 0x27f};
  Exception::LoadStateFromECContext(Thread, CPUArea.ContextAmd64().AMD64_Context);

  {
    auto ThreadTID = GetCurrentThreadId();
    Threads.emplace(ThreadTID, Thread);
    if (StatAllocHandler) {
      Thread->ThreadStats = StatAllocHandler->AllocateSlot(ThreadTID);