Function LoadStateFromWowContext

Source/Windows/WOW64/Module.cpp:201–249

namespace Context {
void LoadStateFromWowContext(FEXCore::Core::InternalThreadState* Thread, uint64_t WowTEB, WOW64_CONTEXT* Context) {
  auto& State = Thread->CurrentFrame->State;

  // General register state

  State.gregs[FEXCore::X86State::REG_RAX] = Context->Eax;
  State.gregs[FEXCore::X86State::REG_RBX] = Context->Ebx;
  State.gregs[FEXCore::X86State::REG_RCX] = Context->Ecx;
  State.gregs[FEXCore::X86State::REG_RDX] = Context->Edx;
  State.gregs[FEXCore::X86State::REG_RSI] = Context->Esi;
  State.gregs[FEXCore::X86State::REG_RDI] = Context->Edi;
  State.gregs[FEXCore::X86State::REG_RBP] = Context->Ebp;
  State.gregs[FEXCore::X86State::REG_RSP] = Context->Esp;

  State.rip = Context->Eip;
  CTX->SetFlagsFromCompactedEFLAGS(Thread, Context->EFlags);

  State.es_idx = Context->SegEs & 0xffff;
  State.cs_idx = Context->SegCs & 0xffff;
  State.ss_idx = Context->SegSs & 0xffff;
  State.ds_idx = Context->SegDs & 0xffff;
  State.fs_idx = Context->SegFs & 0xffff;
  State.gs_idx = Context->SegGs & 0xffff;

  // The TEB is the only populated GDT entry by default
  auto GDT = State.GetSegmentFromIndex(State, (Context->SegFs & 0xffff));
  State.SetGDTBase(GDT, WowTEB);
  State.SetGDTLimit(GDT, 0xF'FFFFU);
  State.fs_cached = WowTEB;
  State.es_cached = 0;
  State.cs_cached = 0;
  State.ss_cached = 0;
  State.ds_cached = 0;

  // Floating-point register state
  const auto* XSave = reinterpret_cast<XSAVE_FORMAT*>(Context->ExtendedRegisters);

  CTX->SetXMMRegistersFromState(Thread, reinterpret_cast<const __uint128_t*>(XSave->XmmRegisters), nullptr);
  memcpy(State.mm, XSave->FloatRegisters, sizeof(State.mm));

  State.FCW = XSave->ControlWord;
  State.flags[FEXCore::X86State::X87FLAG_IE_LOC] = XSave->StatusWord & 1;
  State.flags[FEXCore::X86State::X87FLAG_C0_LOC] = (XSave->StatusWord >> 8) & 1;
  State.flags[FEXCore::X86State::X87FLAG_C1_LOC] = (XSave->StatusWord >> 9) & 1;
  State.flags[FEXCore::X86State::X87FLAG_C2_LOC] = (XSave->StatusWord >> 10) & 1;
  State.flags[FEXCore::X86State::X87FLAG_C3_LOC] = (XSave->StatusWord >> 14) & 1;
  State.flags[FEXCore::X86State::X87FLAG_TOP_LOC] = (XSave->StatusWord >> 11) & 0b111;
  State.AbridgedFTW = XSave->TagWord;
}

void StoreWowContextFromState(FEXCore::Core::InternalThreadState* Thread, WOW64_CONTEXT* Context) {
  auto& State = Thread->CurrentFrame->State;