ref: af25b58d05b0700990057ce3f8c853bd43f2ece0 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