user: Please show me the C implementation that matches the assembly code listed below:

```asm
<fib>:
  endbr64
  mov    %edi,%r10d
  test   %edi,%edi
  je     L394
  cmp    $0x1,%edi
  je     L394
  push   %r15
  lea    -0x2(%rdi),%eax
  xor    %r10d,%r10d
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x38,%rsp
  mov    %eax,0x8(%rsp)
  mov    %r10d,0x10(%rsp)
L481:
  mov    0x8(%rsp),%edi
  mov    %edi,%eax
  add    $0x1,%eax
  je     L110
  cmp    $0x1,%eax
  je     L144
  lea    -0x1(%rdi),%eax
  xor    %r8d,%r8d
  mov    %eax,0x4(%rsp)
  mov    %r8d,0x14(%rsp)
L16:
  mov    0x4(%rsp),%edi
  mov    %edi,%eax
  add    $0x1,%eax
  je     L241
  cmp    $0x1,%eax
  je     L67
  lea    -0x1(%rdi),%eax
  xor    %ecx,%ecx
  mov    %eax,0xc(%rsp)
  mov    %ecx,0x18(%rsp)
L301:
  mov    0xc(%rsp),%edi
  mov    %edi,%eax
  add    $0x1,%eax
  je     L281
  cmp    $0x1,%eax
  je     L133
  xor    %ecx,%ecx
  lea    -0x1(%rdi),%r8d
  mov    %ecx,0x1c(%rsp)
  mov    %r8d,%ecx
L211:
  mov    %ecx,%eax
  add    $0x1,%eax
  je     L462
  cmp    $0x1,%eax
  je     L392
  xor    %esi,%esi
  mov    %ecx,0x20(%rsp)
  lea    -0x1(%rcx),%r9d
  mov    %esi,(%rsp)
  mov    %r9d,%r15d
L47:
  mov    %r15d,%eax
  add    $0x1,%eax
  je     L439
  cmp    $0x1,%eax
  je     L90
  lea    -0x1(%r15),%r12d
  xor    %ecx,%ecx
  mov    %r15d,%esi
L48:
  mov    %r12d,%eax
  add    $0x1,%eax
  je     L410
  cmp    $0x1,%eax
  je     L449
  xor    %ebx,%ebx
  lea    -0x1(%r12),%ebp
  mov    %r12d,%edx
  mov    %ebx,%r12d
L3:
  mov    %ebp,%eax
  add    $0x1,%eax
  je     L166
  cmp    $0x1,%eax
  je     L98
  mov    %ebp,%eax
  lea    -0x1(%rbp),%ebx
  xor    %r14d,%r14d
  mov    %ecx,%ebp
  mov    %eax,%ecx
L487:
  mov    %ebx,%r13d
  add    $0x1,%r13d
  je     L527
  cmp    $0x1,%r13d
  je     L326
  mov    %ebx,0x24(%rsp)
  xor    %r15d,%r15d
  mov    %esi,%ebx
L102:
  lea    -0x1(%r13),%edi
  mov    %ecx,0x2c(%rsp)
  mov    %edx,0x28(%rsp)
  call   <fib>
  mov    0x28(%rsp),%edx
  mov    0x2c(%rsp),%ecx
  add    %eax,%r15d
  sub    $0x2,%r13d
  je     L371
  cmp    $0x1,%r13d
  jne    L102
  mov    %ebx,%esi
  mov    0x24(%rsp),%ebx
  add    $0x1,%r15d
L30:
  add    %r15d,%r14d
  test   %ebx,%ebx
  je     L315
  cmp    $0x1,%ebx
  jne    L527
L326:
  mov    %ecx,%eax
  add    $0x1,%r14d
  mov    %ebp,%ecx
  mov    %eax,%ebp
  add    %r14d,%r12d
  test   %ebp,%ebp
  je     L186
L148:
  cmp    $0x1,%ebp
  jne    L166
L98:
  mov    %r12d,%ebx
  mov    %edx,%r12d
  add    $0x1,%ebx
L21:
  add    %ebx,%ecx
  test   %r12d,%r12d
  jne    L164
  mov    %esi,%r15d
  mov    %ecx,%r14d
  add    %r14d,(%rsp)
  mov    (%rsp),%esi
  test   %r15d,%r15d
  jne    L269
L108:
  mov    0x20(%rsp),%ecx
  add    %esi,0x1c(%rsp)
  test   %ecx,%ecx
  je     L288
L162:
  cmp    $0x1,%ecx
  je     L392
L462:
  sub    $0x2,%ecx
  jmp    L211
L166:
  sub    $0x2,%ebp
  jmp    L3
L164:
  cmp    $0x1,%r12d
  jne    L410
L449:
  mov    %ecx,%r14d
  mov    %esi,%r15d
  add    $0x1,%r14d
  add    %r14d,(%rsp)
  mov    (%rsp),%esi
  test   %r15d,%r15d
  je     L108
L269:
  cmp    $0x1,%r15d
  je     L90
L439:
  sub    $0x2,%r15d
  jmp    L47
L410:
  sub    $0x2,%r12d
  jmp    L48
L315:
  mov    %ecx,%eax
  mov    %ebp,%ecx
  add    %r14d,%r12d
  mov    %eax,%ebp
  test   %ebp,%ebp
  jne    L148
L186:
  mov    %r12d,%ebx
  mov    %edx,%r12d
  jmp    L21
  nopl   (%rax)
L371:
  mov    %ebx,%esi
  mov    0x24(%rsp),%ebx
  jmp    L30
L90:
  mov    (%rsp),%esi
  mov    0x20(%rsp),%ecx
  add    $0x1,%esi
  add    %esi,0x1c(%rsp)
  test   %ecx,%ecx
  jne    L162
L288:
  mov    0x1c(%rsp),%ecx
  add    %ecx,0x18(%rsp)
  mov    0xc(%rsp),%ecx
  test   %ecx,%ecx
  jne    L8
L55:
  mov    0x4(%rsp),%edx
  mov    0x18(%rsp),%ecx
  add    %ecx,0x14(%rsp)
  test   %edx,%edx
  jne    L360
L173:
  mov    0x14(%rsp),%r8d
  jmp    L300
L527:
  sub    $0x2,%ebx
  jmp    L487
L392:
  mov    0x1c(%rsp),%ecx
  add    $0x1,%ecx
  add    %ecx,0x18(%rsp)
  mov    0xc(%rsp),%ecx
  test   %ecx,%ecx
  je     L55
L8:
  cmpl   $0x1,0xc(%rsp)
  je     L133
L281:
  subl   $0x2,0xc(%rsp)
  jmp    L301
L133:
  mov    0x18(%rsp),%ecx
  mov    0x4(%rsp),%edx
  add    $0x1,%ecx
  add    %ecx,0x14(%rsp)
  test   %edx,%edx
  je     L173
L360:
  cmpl   $0x1,0x4(%rsp)
  je     L67
L241:
  subl   $0x2,0x4(%rsp)
  jmp    L16
L67:
  mov    0x14(%rsp),%r8d
  add    $0x1,%r8d
L300:
  mov    0x8(%rsp),%eax
  add    %r8d,0x10(%rsp)
  test   %eax,%eax
  je     L176
  cmpl   $0x1,0x8(%rsp)
  jne    L110
L144:
  mov    0x10(%rsp),%r10d
  add    $0x1,%r10d
L464:
  add    $0x38,%rsp
  mov    %r10d,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L110:
  subl   $0x2,0x8(%rsp)
  jmp    L481
L394:
  mov    %r10d,%eax
  ret
L176:
  mov    0x10(%rsp),%r10d
  jmp    L464
```

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