user: What is the c source code of the assembly code below:

```asm
<extract_bits_big>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %rdi,-0x18(%rbp)
  mov    %rsi,-0x20(%rbp)
  mov    %rdx,-0x28(%rbp)
  mov    %ecx,-0x2c(%rbp)
  mov    -0x20(%rbp),%rax
  mov    (%rax),%eax
  cmp    $0x8,%eax
  jne    L19
  mov    -0x20(%rbp),%rax
  movl   $0x0,(%rax)
  mov    -0x18(%rbp),%rax
  mov    (%rax),%rax
  lea    0x1(%rax),%rdx
  mov    -0x18(%rbp),%rax
  mov    %rdx,(%rax)
  mov    -0x28(%rbp),%rax
  mov    (%rax),%eax
  lea    -0x1(%rax),%edx
  mov    -0x28(%rbp),%rax
  mov    %edx,(%rax)
L19:
  mov    -0x20(%rbp),%rax
  mov    (%rax),%edx
  mov    -0x2c(%rbp),%eax
  add    %edx,%eax
  cmp    $0x8,%eax
  jg     L56
  mov    -0x18(%rbp),%rax
  mov    (%rax),%rax
  movzbl (%rax),%eax
  movzbl %al,%edx
  mov    -0x20(%rbp),%rax
  mov    (%rax),%ecx
  mov    -0x2c(%rbp),%eax
  add    %eax,%ecx
  mov    $0x8,%eax
  sub    %ecx,%eax
  mov    %eax,%ecx
  sar    %cl,%edx
  mov    -0x2c(%rbp),%eax
  mov    $0x1,%esi
  mov    %eax,%ecx
  shl    %cl,%esi
  mov    %esi,%eax
  sub    $0x1,%eax
  and    %edx,%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x20(%rbp),%rax
  mov    (%rax),%edx
  mov    -0x2c(%rbp),%eax
  add    %eax,%edx
  mov    -0x20(%rbp),%rax
  mov    %edx,(%rax)
  jmp    L59
L56:
  mov    -0x20(%rbp),%rax
  mov    (%rax),%edx
  mov    -0x2c(%rbp),%eax
  add    %edx,%eax
  cmp    $0x10,%eax
  jg     L6
  mov    -0x18(%rbp),%rax
  mov    (%rax),%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  shl    $0x8,%eax
  mov    %eax,%edx
  mov    -0x18(%rbp),%rax
  mov    (%rax),%rax
  add    $0x1,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  or     %eax,%edx
  mov    -0x20(%rbp),%rax
  mov    (%rax),%ecx
  mov    -0x2c(%rbp),%eax
  add    %eax,%ecx
  mov    $0x10,%eax
  sub    %ecx,%eax
  mov    %eax,%ecx
  sar    %cl,%edx
  mov    -0x2c(%rbp),%eax
  mov    $0x1,%esi
  mov    %eax,%ecx
  shl    %cl,%esi
  mov    %esi,%eax
  sub    $0x1,%eax
  and    %edx,%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x20(%rbp),%rax
  mov    (%rax),%edx
  mov    -0x2c(%rbp),%eax
  sub    $0x8,%eax
  add    %eax,%edx
  mov    -0x20(%rbp),%rax
  mov    %edx,(%rax)
  mov    -0x18(%rbp),%rax
  mov    (%rax),%rax
  lea    0x1(%rax),%rdx
  mov    -0x18(%rbp),%rax
  mov    %rdx,(%rax)
  mov    -0x28(%rbp),%rax
  mov    (%rax),%eax
  lea    -0x1(%rax),%edx
  mov    -0x28(%rbp),%rax
  mov    %edx,(%rax)
  jmp    L59
L6:
  mov    -0x20(%rbp),%rax
  mov    (%rax),%edx
  mov    -0x2c(%rbp),%eax
  add    %edx,%eax
  cmp    $0x18,%eax
  jg     L59
  mov    -0x18(%rbp),%rax
  mov    (%rax),%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  shl    $0x10,%eax
  mov    %eax,%edx
  mov    -0x18(%rbp),%rax
  mov    (%rax),%rax
  add    $0x1,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  shl    $0x8,%eax
  or     %eax,%edx
  mov    -0x18(%rbp),%rax
  mov    (%rax),%rax
  add    $0x2,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  or     %eax,%edx
  mov    -0x20(%rbp),%rax
  mov    (%rax),%ecx
  mov    -0x2c(%rbp),%eax
  add    %eax,%ecx
  mov    $0x18,%eax
  sub    %ecx,%eax
  mov    %eax,%ecx
  sar    %cl,%edx
  mov    -0x2c(%rbp),%eax
  mov    $0x1,%esi
  mov    %eax,%ecx
  shl    %cl,%esi
  mov    %esi,%eax
  sub    $0x1,%eax
  and    %edx,%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x20(%rbp),%rax
  mov    (%rax),%edx
  mov    -0x2c(%rbp),%eax
  sub    $0x10,%eax
  add    %eax,%edx
  mov    -0x20(%rbp),%rax
  mov    %edx,(%rax)
  mov    -0x18(%rbp),%rax
  mov    (%rax),%rax
  lea    0x2(%rax),%rdx
  mov    -0x18(%rbp),%rax
  mov    %rdx,(%rax)
  mov    -0x28(%rbp),%rax
  mov    (%rax),%eax
  lea    -0x2(%rax),%edx
  mov    -0x28(%rbp),%rax
  mov    %edx,(%rax)
L59:
  mov    -0x4(%rbp),%eax
  pop    %rbp
  ret
```

assistant: ```c
int extract_bits_big(const unsigned char **data, int *bit, int *size, int bits) {
  int x;
  if (*bit == 8) {
    *bit = 0;
    (*data)++, (*size)--;
  }
  if (*bit + bits <= 8) {
    x = ((*data)[0] >> (8 - (*bit + bits))) & ((1 << (bits)) - 1);
    *bit += bits;
  } else if (*bit + bits <= 16) {
    x = ((((*data)[0] << 8) | (*data)[1]) >> (16 - (*bit + bits))) & ((1 << (bits)) - 1);
    *bit += bits - 8;
    (*data)++, (*size)--;
  } else if (*bit + bits <= 24) {
    x = ((((*data)[0] << 16) | (*data)[1] << 8 | (*data)[2]) >> (24 - (*bit + bits))) & ((1 << (bits)) - 1);
    *bit += bits - 16;
    (*data) += 2, (*size) -= 2;
  }
  return x;
}
```