If the asm was written a little more cleverly, the syscalls would avoid almost all moves, because the compiler'd put everything in place: _syscall5: mov

If the asm was written a little more cleverly, the syscalls would avoid almost all moves, because the compiler'd put everything in place: _syscall5: mov %r9, %r10 _syscall3: mov %rcx, %rax syscall ret And then: extern unsigned long _syscall3( unsigned long, unsigned long, unsigned long, unsigned long); extern unsigned long _syscall5( unsigned long, unsigned long, unsigned long, unsigned long, unsigned long, unsigned long); #define syscall0(NUM) _syscall3(0,0,0,NUM) #define syscall1(NUM,A) _syscall3(A,0,0,NUM) #define syscall2(NUM,A,B) _syscall3(A,B,0,NUM) #define syscall3(NUM,A,B,C) _syscall3(A,B,C,NUM) #define syscall4(NUM,A,B,C,D) _syscall5(A,B,C,NUM,0,D) #define syscall5(NUM,A,B,C,D,E) _syscall5(A,B,C,NUM,E,D)