stdlib/getenv.s

   1         .text
   2         .p2align 4,,15
   3         .globl  getenv
   4         .hidden getenv
   5         .type   getenv, @function
   6 getenv:
   7         pushq   %r15
   8         pushq   %r14
   9         pushq   %r13
  10         pushq   %r12
  11         pushq   %rbp
  12         pushq   %rbx
  13         subq    $8, %rsp
  14         movq    __environ(%rip), %rbp
  15         testq   %rbp, %rbp
  16         je      .L10
  17         movzbl  (%rdi), %eax
  18         testb   %al, %al
  19         je      .L10
  20         cmpb    $0, 1(%rdi)
  21         movq    0(%rbp), %rbx
  22         jne     .L3
  23         orb     $61, %ah
  24         testq   %rbx, %rbx
  25         jne     .L6
  26         jmp     .L1
  27         .p2align 4,,10
  28         .p2align 3
  29 .L5:
  30         addq    $8, %rbp
  31         movq    0(%rbp), %rbx
  32         testq   %rbx, %rbx
  33         je      .L1
  34 .L6:
  35         cmpw    (%rbx), %ax
  36         jne     .L5
  37         addq    $2, %rbx
  38 .L1:
  39         addq    $8, %rsp
  40         movq    %rbx, %rax
  41         popq    %rbx
  42         popq    %rbp
  43         popq    %r12
  44         popq    %r13
  45         popq    %r14
  46         popq    %r15
  47         ret
  48         .p2align 4,,10
  49         .p2align 3
  50 .L3:
  51         movq    %rdi, %r13
  52         addq    $2, %r13
  53         call    strlen
  54         movzwl  -2(%r13), %r12d
  55         testq   %rbx, %rbx
  56         movq    %rax, %r15
  57         leaq    -2(%rax), %r14
  58         jne     .L8
  59         jmp     .L1
  60         .p2align 4,,10
  61         .p2align 3
  62 .L7:
  63         addq    $8, %rbp
  64         movq    0(%rbp), %rbx
  65         testq   %rbx, %rbx
  66         je      .L1
  67 .L8:
  68         cmpw    (%rbx), %r12w
  69         jne     .L7
  70         leaq    2(%rbx), %rdi
  71         movq    %r14, %rdx
  72         movq    %r13, %rsi
  73         call    strncmp
  74         testl   %eax, %eax
  75         jne     .L7
  76         cmpb    $61, (%rbx,%r15)
  77         jne     .L7
  78         leaq    1(%rbx,%r15), %rbx
  79         jmp     .L1
  80         .p2align 4,,10
  81         .p2align 3
  82 .L10:
  83         xorl    %ebx, %ebx
  84         jmp     .L1
  85         .size   getenv, .-getenv
  86         .hidden strncmp
  87         .hidden strlen