Method HandleSyscallImpl

Source/Windows/WOW64/Module.cpp:431–465

  }

  static uint64_t HandleSyscallImpl(FEXCore::Core::CpuStateFrame* Frame, FEXCore::HLE::SyscallArguments* Args) {
    const uint64_t ReturnRIP = *(uint32_t*)(Frame->State.gregs[FEXCore::X86State::REG_RSP]); // Return address from the stack
    uint64_t ReturnRSP = Frame->State.gregs[FEXCore::X86State::REG_RSP] + 4;                 // Stack pointer after popping return address
    uint64_t ReturnRAX = 0;

    if (Frame->State.rip == (uint64_t)BridgeInstrs::UnixCall) {
      struct StackLayout {
        unixlib_handle_t Handle;
        UINT32 ID;
        ULONG32 Args;
      }* StackArgs = reinterpret_cast<StackLayout*>(ReturnRSP);

      ReturnRSP += sizeof(StackLayout);

      Context::UnlockJITContext();
      ReturnRAX = static_cast<uint64_t>(WineUnixCall(StackArgs->Handle, StackArgs->ID, ULongToPtr(StackArgs->Args)));
      Context::LockJITContext();
    } else if (Frame->State.rip == (uint64_t)BridgeInstrs::Syscall) {
      const uint64_t EntryRAX = Frame->State.gregs[FEXCore::X86State::REG_RAX];

      Context::UnlockJITContext();
      Wow64ProcessPendingCrossProcessItems();
      ReturnRAX = static_cast<uint64_t>(Wow64SystemServiceEx(static_cast<UINT>(EntryRAX), reinterpret_cast<UINT*>(ReturnRSP + 4)));
      Context::LockJITContext();
    }
    // If a new context has been set, use it directly and don't return to the syscall caller
    if (Frame->State.rip == (uint64_t)BridgeInstrs::Syscall || Frame->State.rip == (uint64_t)BridgeInstrs::UnixCall) {
      Frame->State.gregs[FEXCore::X86State::REG_RAX] = ReturnRAX;
      Frame->State.gregs[FEXCore::X86State::REG_RSP] = ReturnRSP;
      Frame->State.rip = ReturnRIP;
    }

    // NORETURNEDRESULT causes this result to be ignored since we restore all registers back from memory after a syscall anyway
    return 0;
  }

  uint64_t HandleSyscall(FEXCore::Core::CpuStateFrame* Frame, FEXCore::HLE::SyscallArguments* Args) override {
    // Stash the the context pointer on the stack, as Simulate can be called from this syscall handler which would overwrite it