user: 请从给定的汇编指令推导出C源代码：

```asm
<fib>:
  endbr64
  test   %edi,%edi
  je     L90
  cmp    $0x1,%edi
  je     L147
  push   %r15
  xor    %r11d,%r11d
  mov    %edi,%r9d
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x58,%rsp
  mov    %r11,(%rsp)
L151:
  lea    -0x1(%r9),%eax
  xor    %r11d,%r11d
  mov    %r9d,0x48(%rsp)
  mov    %eax,0x40(%rsp)
  mov    %r11,0x8(%rsp)
L3:
  mov    0x40(%rsp),%eax
  cmp    $0x1,%eax
  je     L242
  sub    $0x1,%eax
  xor    %esi,%esi
  mov    %eax,0x44(%rsp)
  mov    %rsi,0x10(%rsp)
L56:
  mov    0x44(%rsp),%eax
  cmp    $0x1,%eax
  je     L287
  xor    %esi,%esi
  lea    -0x1(%rax),%r9d
  mov    %rsi,0x18(%rsp)
  mov    %r9d,%esi
L250:
  cmp    $0x1,%esi
  je     L86
  xor    %r8d,%r8d
  mov    %esi,0x4c(%rsp)
  lea    -0x1(%rsi),%r10d
  mov    %r8,0x20(%rsp)
  mov    %r10d,%r15d
L49:
  cmp    $0x1,%r15d
  je     L186
  lea    -0x1(%r15),%r12d
  mov    %r15d,%ecx
  xor    %r8d,%r8d
  mov    %r12d,%r15d
L98:
  cmp    $0x1,%r15d
  je     L7
  xor    %r13d,%r13d
  lea    -0x1(%r15),%ebx
  mov    %r15d,%edx
  mov    %r13,%r15
L119:
  cmp    $0x1,%ebx
  je     L95
  mov    %r15,%rax
  lea    -0x1(%rbx),%r13d
  mov    %ebx,%r15d
  xor    %r12d,%r12d
  mov    %ecx,%ebx
  mov    %rax,%rcx
L230:
  cmp    $0x1,%r13d
  je     L24
  mov    %r13d,0x2c(%rsp)
  lea    -0x1(%r13),%ebp
  xor    %r14d,%r14d
  mov    %r8,%r13
  mov    %r12,0x30(%rsp)
  mov    %edx,%r12d
L195:
  cmp    $0x1,%ebp
  je     L41
  lea    -0x1(%rbp),%edi
  mov    %rcx,0x38(%rsp)
  call   <fib>
  mov    0x38(%rsp),%rcx
  add    %rax,%r14
  sub    $0x2,%ebp
  jne    L195
  mov    %r12d,%edx
  mov    %r13,%r8
  mov    0x30(%rsp),%r12
  mov    0x2c(%rsp),%r13d
L241:
  add    %r14,%r12
  sub    $0x2,%r13d
  jne    L230
  mov    %rcx,%rax
  mov    %ebx,%ecx
  mov    %r15d,%ebx
  mov    %rax,%r15
L190:
  add    %r12,%r15
  sub    $0x2,%ebx
  jne    L119
  mov    %r15,%r13
  mov    %edx,%r15d
L280:
  add    %r13,%r8
  sub    $0x2,%r15d
  jne    L98
  mov    %ecx,%r15d
L291:
  add    %r8,0x20(%rsp)
  sub    $0x2,%r15d
  jne    L49
  mov    0x4c(%rsp),%esi
  mov    0x20(%rsp),%r8
L50:
  add    %r8,0x18(%rsp)
  sub    $0x2,%esi
  jne    L250
  mov    0x18(%rsp),%rsi
L238:
  add    %rsi,0x10(%rsp)
  subl   $0x2,0x44(%rsp)
  jne    L56
  mov    0x10(%rsp),%rsi
L263:
  add    %rsi,0x8(%rsp)
  subl   $0x2,0x40(%rsp)
  jne    L3
  mov    0x48(%rsp),%r9d
  mov    0x8(%rsp),%r11
  add    %r11,(%rsp)
  sub    $0x2,%r9d
  jne    L148
L127:
  mov    (%rsp),%r11
  jmp    L1
  nopl   0x0(%rax,%rax,1)
L41:
  mov    %r12d,%edx
  mov    %r13,%r8
  mov    0x30(%rsp),%r12
  mov    0x2c(%rsp),%r13d
  add    $0x1,%r14
  jmp    L241
  nopl   0x0(%rax)
L24:
  mov    %rcx,%rax
  add    $0x1,%r12
  mov    %ebx,%ecx
  mov    %r15d,%ebx
  mov    %rax,%r15
  jmp    L190
L7:
  mov    %ecx,%r15d
  add    $0x1,%r8
  jmp    L291
L95:
  mov    %r15,%r13
  mov    %edx,%r15d
  add    $0x1,%r13
  jmp    L280
L186:
  mov    0x20(%rsp),%r8
  mov    0x4c(%rsp),%esi
  add    $0x1,%r8
  jmp    L50
L86:
  mov    0x18(%rsp),%rsi
  add    $0x1,%rsi
  jmp    L238
L287:
  mov    0x10(%rsp),%rsi
  add    $0x1,%rsi
  jmp    L263
L242:
  mov    0x8(%rsp),%r11
  mov    0x48(%rsp),%r9d
  add    $0x1,%r11
  add    %r11,(%rsp)
  sub    $0x2,%r9d
  je     L127
L148:
  cmp    $0x1,%r9d
  jne    L151
  mov    (%rsp),%r11
  add    $0x1,%r11
L1:
  add    $0x58,%rsp
  mov    %r11,%rax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L90:
  xor    %r11d,%r11d
L267:
  mov    %r11,%rax
  ret
L147:
  mov    $0x1,%r11d
  jmp    L267
```

assistant: ```c
unsigned long long fib(unsigned int n) {
  if (n == 0)
    return 0;
  if (n == 1)
    return 1;
  return fib(n - 1) + fib(n - 2);
}
```