It's not just the registers, the use of the stack (e.g. lack of a "red zone" on Windows) as well as the data used for exception handling are different too. The

It's not just the registers, the use of the stack (e.g. lack of a "red zone" on Windows) as well as the data used for exception handling are different too. The MSDN links above are quite detailed on what Windows implements. The post by Eli at https://eli.thegreenplace.net/2011/09/06/stack-frame-layout-on-x86-64/ https://eli.thegreenplace.net/2011/09/06/stack-frame-layout-... goes over some Windows differences towards the end.