libio/getchar_u.s

   1         .text
   2         .p2align 4,,15
   3         .globl  getchar_unlocked
   4         .type   getchar_unlocked, @function
   5 getchar_unlocked:
   6         movq    stdin(%rip), %rdi
   7         movq    8(%rdi), %rax
   8         cmpq    16(%rdi), %rax
   9         jnb     .L4
  10         leaq    1(%rax), %rdx
  11         movq    %rdx, 8(%rdi)
  12         movzbl  (%rax), %eax
  13         ret
  14         .p2align 4,,10
  15         .p2align 3
  16 .L4:
  17         jmp     __uflow
  18         .size   getchar_unlocked, .-getchar_unlocked
  19         .hidden __uflow