I find Heaven's Gate very interesting. Though I can manually enter 64-bit mode by switching the value of CS to 0x33, it's hard to do any IO -- I can only do simple arithmatic operations.
I know I can access the 64-bit PEB structure by R12 and then obtain a pointer to the module of 64-bit ntdll.dll and thus invoke its functions, such as LdrGetProcedureAddress and LdrLoadDll. But my program crashes on loading the 64-bit kernel32.dll, and it creates an extra console.
Does that means, I can only do normal IO operations back in the WOW64 mode?