Inline asm in iOS error

Question

int x;
__asm __volatile("movl %0, %%sp":"=r"(x)::"%sp");
I want to store sp to x.
The error:

error: unexpected token in operand
    __asm __volatile("movl  %0,  %%sp":"=r"(x)::"%sp");
                     ^
:1:13: note: instantiated into assembly here
        movl  r0,  %sp
                   ^
1 warning and 1 error generated.

Answer 1

I have found my solution:

asm volatile("mov %0, sp \n\t":"=r"(x));