n: int     # . prologue     00/push-ebp     00/<- %ebp 0/r00/esp     # . save registers     00/push-ecx     # var buf/ecx: (stream byte 00)     00 0/subop/subtract %esp 0x00/imm00     00/push 0x00/imm00/size     00/push 0/imm00/read     00/push 0/imm00/write     00/<- %ecx 0/r00/esp     # construct directive in buf     