ABI64 and register save area

Hi, I that hope this is the right place for this kind of questions! However my question is rather simple: knowing the AMD64 ABI, is it possible to implement your own flavour of the va_xxx macros? If I compile _without_ -fomit-frame-pointer I'm able to retrieve the arguments pushed on the stack, bu

[GCC 4.x][AMD64 ABI] variadic function

Hi to everyone, I cannot figure out how variadic function are practically implemented. In the called (variadic) function after few 'push's %rsp is suddenly decremented by N bytes: the red area starts 128 bytes below the NEW rsp or %rsp-N above? Is it possible to find the register save area and th