=> 0x7f892d60f9c0: mov 0x20(%rdi),%eax 0x7f892d60f9c3: shr $0x2,%eax 0x7f892d60f9c6: and $0x1,%eax 0x7f892d60f9c9: retq 0x7f892d60f9ca: nopw 0x0(%rax,%rax,1) 0x7f892d60f9d0 : test %rdi,%rdi 0x7f892d60f9d3 : push %rbx 0x7f892d60f9d4 : mov %rdi,%rbx 0x7f892d60f9d7 : je 0x7f892d60faa0 0x7f892d60f9dd : mov 0x24(%rdi),%eax 0x7f892d60f9e0 : test %eax,%eax 0x7f892d60f9e2 : jle 0x7f892d60fa70 0x7f892d60f9e8 : lock subl $0x1,0x24(%rdi) 0x7f892d60f9ed : je 0x7f892d60f9f8 0x7f892d60f9ef : pop %rbx 0x7f892d60f9f0 : retq