ref: 07c3fc899a4788187f52b99961c7ae1777201d5b dir: /lib/c/arch/amd64/linux/_cerrno.s/
.file "_cerrno.s" .globl _cerrno _cerrno: cmpq $0,%rax js 1f retq 1: neg %rax mov %eax,(errno) mov $-1,%eax retq