user: What would the C source look like for the assembly code provided here?

```asm
<strtoull>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x50,%rsp
  mov    %rdi,-0x38(%rbp)
  mov    %rsi,-0x40(%rbp)
  mov    %edx,-0x44(%rbp)
  mov    -0x38(%rbp),%rax
  mov    %rax,-0x18(%rbp)
L184:
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  movzbl (%rax),%eax
  mov    %al,-0x25(%rbp)
  movzbl -0x25(%rbp),%eax
  movzbl %al,%eax
  mov    %eax,%edi
  call   <isspace@plt>
  test   %rax,%rax
  jne    L184
  cmpb   $0x2d,-0x25(%rbp)
  jne    L366
  movl   $0x1,-0x24(%rbp)
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  movzbl (%rax),%eax
  mov    %al,-0x25(%rbp)
  jmp    L191
L366:
  movl   $0x0,-0x24(%rbp)
  cmpb   $0x2b,-0x25(%rbp)
  jne    L191
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  movzbl (%rax),%eax
  mov    %al,-0x25(%rbp)
L191:
  cmpl   $0x0,-0x44(%rbp)
  je     L52
  cmpl   $0x10,-0x44(%rbp)
  jne    L369
L52:
  cmpb   $0x30,-0x25(%rbp)
  jne    L369
  mov    -0x18(%rbp),%rax
  movzbl (%rax),%eax
  cmp    $0x78,%al
  je     L309
  mov    -0x18(%rbp),%rax
  movzbl (%rax),%eax
  cmp    $0x58,%al
  jne    L369
L309:
  mov    -0x18(%rbp),%rax
  add    $0x1,%rax
  movzbl (%rax),%eax
  mov    %al,-0x25(%rbp)
  addq   $0x2,-0x18(%rbp)
  movl   $0x10,-0x44(%rbp)
L369:
  cmpl   $0x0,-0x44(%rbp)
  jne    L192
  cmpb   $0x30,-0x25(%rbp)
  jne    L86
  mov    $0x8,%eax
  jmp    L300
L86:
  mov    $0xa,%eax
L300:
  mov    %eax,-0x44(%rbp)
L192:
  movl   $0x0,-0x20(%rbp)
  movq   $0x0,-0x10(%rbp)
  cmpl   $0x1,-0x44(%rbp)
  jle    L227
  cmpl   $0x24,-0x44(%rbp)
  jg     L227
  mov    D20(%rip),%rax
  mov    (%rax),%eax
  cltd
  idivl  -0x44(%rbp)
  cltq
  mov    %rax,-0x8(%rbp)
  mov    D20(%rip),%rax
  mov    (%rax),%eax
  cltd
  idivl  -0x44(%rbp)
  mov    %edx,-0x1c(%rbp)
L200:
  cmpb   $0x2f,-0x25(%rbp)
  jle    L69
  cmpb   $0x39,-0x25(%rbp)
  jg     L69
  movzbl -0x25(%rbp),%eax
  sub    $0x30,%eax
  mov    %al,-0x25(%rbp)
  jmp    L111
L69:
  cmpb   $0x40,-0x25(%rbp)
  jle    L326
  cmpb   $0x5a,-0x25(%rbp)
  jg     L326
  movzbl -0x25(%rbp),%eax
  sub    $0x37,%eax
  mov    %al,-0x25(%rbp)
  jmp    L111
L326:
  cmpb   $0x60,-0x25(%rbp)
  jle    L189
  cmpb   $0x7a,-0x25(%rbp)
  jg     L189
  movzbl -0x25(%rbp),%eax
  sub    $0x57,%eax
  mov    %al,-0x25(%rbp)
L111:
  movsbl -0x25(%rbp),%eax
  cmp    %eax,-0x44(%rbp)
  jle    L348
  cmpl   $0x0,-0x20(%rbp)
  js     L106
  mov    -0x10(%rbp),%rax
  cmp    -0x8(%rbp),%rax
  ja     L106
  mov    -0x10(%rbp),%rax
  cmp    -0x8(%rbp),%rax
  jne    L46
  movsbl -0x25(%rbp),%eax
  cmp    %eax,-0x1c(%rbp)
  jge    L46
L106:
  movl   $0xffffffff,-0x20(%rbp)
  jmp    L38
L46:
  movl   $0x1,-0x20(%rbp)
  mov    -0x44(%rbp),%eax
  cltq
  mov    -0x10(%rbp),%rdx
  imul   %rdx,%rax
  mov    %rax,-0x10(%rbp)
  movsbq -0x25(%rbp),%rax
  add    %rax,-0x10(%rbp)
L38:
  mov    -0x18(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x18(%rbp)
  movzbl (%rax),%eax
  mov    %al,-0x25(%rbp)
  jmp    L200
L348:
  nop
L189:
  cmpl   $0x0,-0x20(%rbp)
  jns    L104
  mov    D20(%rip),%rax
  mov    (%rax),%eax
  cltq
  mov    %rax,-0x10(%rbp)
  jmp    L174
L104:
  cmpl   $0x0,-0x20(%rbp)
  jne    L307
  jmp    L256
L227:
  nop
L256:
  movq   $0x0,-0x10(%rbp)
  jmp    L174
L307:
  cmpl   $0x0,-0x24(%rbp)
  je     L174
  negq   -0x10(%rbp)
L174:
  cmpq   $0x0,-0x40(%rbp)
  je     L297
  cmpl   $0x0,-0x20(%rbp)
  je     L318
  mov    -0x18(%rbp),%rax
  sub    $0x1,%rax
  jmp    L287
L318:
  mov    -0x38(%rbp),%rax
L287:
  mov    -0x40(%rbp),%rdx
  mov    %rax,(%rdx)
L297:
  mov    -0x10(%rbp),%rax
  leave
  ret
```

assistant: ```c
unsigned long long strtoull(const char *__restrict nptr, char **__restrict endptr, int base) {
  const char *s;
  unsigned long long acc;
  char c;
  unsigned long long cutoff;
  int neg, any, cutlim;
  s = nptr;
  do {
    c = *s++;
  } while (isspace((unsigned char)c));
  if (c == '-') {
    neg = 1;
    c = *s++;
  } else {
    neg = 0;
    if (c == '+')
      c = *s++;
  }
  if ((base == 0 || base == 16) && c == '0' && (*s == 'x' || *s == 'X')) {
    c = s[1];
    s += 2;
    base = 16;
  }
  if (base == 0)
    base = c == '0' ? 8 : 10;
  acc = any = 0;
  if (base < 2 || base > 36)
    goto noconv;
  cutoff = ULLONG_MAX / base;
  cutlim = ULLONG_MAX % base;
  for (;; c = *s++) {
    if (c >= '0' && c <= '9')
      c -= '0';
    else if (c >= 'A' && c <= 'Z')
      c -= 'A' - 10;
    else if (c >= 'a' && c <= 'z')
      c -= 'a' - 10;
    else
      break;
    if (c >= base)
      break;
    if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
      any = -1;
    else {
      any = 1;
      acc *= base;
      acc += c;
    }
  }
  if (any < 0) {
    acc = ULLONG_MAX;
  } else if (!any) {
  noconv:
    acc = 0;
  } else if (neg)
    acc = -acc;
  if (endptr != NULL)
    *endptr = (char *)(any ? s - 1 : nptr);
  return (acc);
}
```