user: Translate the below assembly code into C programming language:

```asm
<strtoxl>:
  endbr64
  push   %r15
  lea    0x1(%rdi),%r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  mov    %edx,%ebp
  push   %rbx
  mov    %ecx,%ebx
  sub    $0x28,%rsp
  movsbl (%rdi),%r13d
  mov    %rdi,0x18(%rsp)
  mov    %rsi,0x10(%rsp)
  jmp    L29
  nopw   0x0(%rax,%rax,1)
L341:
  movsbl (%r15),%r13d
  add    $0x1,%r15
L29:
  movsbl %r13b,%edi
  call   <isspace@plt>
  test   %rax,%rax
  jne    L341
  cmp    $0x2d,%r13b
  je     L0
  cmp    $0x2b,%r13b
  je     L2
L159:
  mov    %ebp,%r14d
  cmp    $0x1,%ebp
  je     L423
  cmp    $0x24,%ebp
  ja     L423
  test   %ebp,%ebp
  jne    L348
  mov    $0xa,%r14d
  mov    $0xa,%ebp
  cmp    $0x30,%r13b
  je     L391
L305:
  mov    D102(%rip),%rax
  xor    %r12d,%r12d
  mov    (%rax),%eax
  cltd
  idiv   %ebp
  cltq
  mov    %rax,(%rsp)
  movslq %ebp,%rax
  mov    %rax,0x8(%rsp)
  jmp    L132
  nopl   0x0(%rax,%rax,1)
L178:
  je     L24
L89:
  or     $0xc,%ebx
L53:
  movsbl (%r15),%r13d
  add    $0x1,%r15
L132:
  mov    %r13d,%edi
  call   <isdigit@plt>
  lea    -0x30(%r13),%ecx
  test   %rax,%rax
  je     L425
  cmp    %r14d,%ecx
  jae    L54
L306:
  cmp    (%rsp),%r12
  jae    L178
  imul   0x8(%rsp),%r12
  or     $0x8,%ebx
  add    %rcx,%r12
  jmp    L53
  nopl   0x0(%rax,%rax,1)
L423:
  mov    0x10(%rsp),%rax
  xor    %r12d,%r12d
  test   %rax,%rax
  je     L187
  mov    0x18(%rsp),%rsi
  mov    %rsi,(%rax)
L187:
  add    $0x28,%rsp
  mov    %r12,%rax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopw   0x0(%rax,%rax,1)
L2:
  movsbl (%r15),%r13d
  add    $0x1,%r15
  jmp    L159
  nopl   (%rax)
L425:
  mov    %r13d,%edi
  call   <isalpha@plt>
  test   %rax,%rax
  je     L54
  mov    %r13d,%edi
  call   <toupper@plt>
  movsbl %al,%ecx
  sub    $0x37,%ecx
  cmp    %r14d,%ecx
  jb     L306
L54:
  mov    %ebx,%eax
  lea    -0x1(%r15),%rsi
  and    $0x2,%eax
  test   $0x8,%bl
  jne    L78
  xor    %r12d,%r12d
  cmpq   $0x0,0x10(%rsp)
  je     L373
L399:
  mov    0x10(%rsp),%rsi
  mov    0x18(%rsp),%rbx
  mov    %rbx,(%rsi)
L373:
  test   %eax,%eax
  je     L187
L63:
  neg    %r12
  jmp    L187
  nop
L24:
  mov    D102(%rip),%rax
  mov    (%rax),%eax
  cltd
  idiv   %ebp
  movslq %edx,%rdx
  cmp    %rdx,%rcx
  ja     L89
  imul   0x8(%rsp),%r12
  or     $0x8,%ebx
  add    %rcx,%r12
  jmp    L53
  nopl   0x0(%rax)
L0:
  movsbl (%r15),%r13d
  or     $0x2,%ebx
  add    $0x1,%r15
  jmp    L159
L78:
  mov    %ebx,%edx
  and    $0x1,%edx
  and    $0x4,%ebx
  je     L312
  mov    D66(%rip),%rcx
  mov    (%rcx),%edi
  mov    D79(%rip),%rcx
  mov    %edi,(%rcx)
  test   %edx,%edx
  je     L365
  mov    D102(%rip),%rbx
  movslq (%rbx),%r12
L16:
  cmpq   $0x0,0x10(%rsp)
  je     L373
  mov    %rsi,0x18(%rsp)
  jmp    L399
L348:
  cmp    $0x10,%ebp
  jne    L305
  cmp    $0x30,%r13b
  jne    L305
  movzbl (%r15),%eax
  and    $0xffffffdf,%eax
  cmp    $0x58,%al
  jne    L305
L436:
  movsbl 0x1(%r15),%r13d
  mov    $0x10,%r14d
  add    $0x2,%r15
  mov    $0x10,%ebp
  jmp    L305
  nopl   0x0(%rax,%rax,1)
L312:
  test   %edx,%edx
  jne    L16
  test   %eax,%eax
  je     L106
  mov    D59(%rip),%rdx
  cmp    %r12,(%rdx)
  jbe    L47
L155:
  mov    D66(%rip),%rdx
  mov    (%rdx),%ecx
  mov    D79(%rip),%rdx
  mov    %ecx,(%rdx)
L365:
  test   %eax,%eax
  je     L362
  mov    D59(%rip),%rdx
  mov    (%rdx),%r12
L47:
  cmpq   $0x0,0x10(%rsp)
  mov    %rsi,0x18(%rsp)
  jne    L399
  jmp    L63
L391:
  movzbl (%r15),%eax
  and    $0xffffffdf,%eax
  cmp    $0x58,%al
  je     L436
  mov    $0x8,%r14d
  mov    $0x8,%ebp
  jmp    L305
L362:
  mov    D30(%rip),%rdx
  mov    (%rdx),%r12
L4:
  cmpq   $0x0,0x10(%rsp)
  mov    %rsi,0x18(%rsp)
  jne    L399
  jmp    L187
L106:
  mov    D30(%rip),%rdx
  cmp    %r12,(%rdx)
  jb     L155
  jmp    L4
```

assistant: ```c
unsigned long strtoxl(const char *nptr, char **endptr, int ibase, int flags) {
  const char *p;
  char c;
  unsigned long number;
  unsigned digval;
  unsigned long maxval;
  p = (const char *)nptr;
  number = 0;
  c = *p++;
  while (isspace(c))
    c = *p++;
  if (c == '-') {
    flags |= 2;
    c = *p++;
  } else if (c == '+') {
    c = *p++;
  }
  if (ibase < 0 || ibase == 1 || ibase > 36) {
    if (endptr)
      *endptr = (char *)nptr;
    return 0L;
  } else if (ibase == 0) {
    if (c != '0') {
      ibase = 10;
    } else if (*p == 'x' || *p == 'X') {
      ibase = 16;
    } else {
      ibase = 8;
    }
  }
  if (ibase == 16) {
    if (c == '0' && (*p == 'x' || *p == 'X')) {
      ++p;
      c = *p++;
    }
  }
  maxval = UINT32_MAX / ibase;
  for (;;) {
    if (isdigit(c)) {
      digval = c - '0';
    } else if (isalpha(c)) {
      digval = toupper(c) - 'A' + 10;
    } else {
      break;
    }
    if (digval >= (unsigned)ibase)
      break;
    flags |= 8;
    if (number < maxval || (number == maxval && (unsigned long)digval <= UINT32_MAX % ibase)) {
      number = number * ibase + digval;
    } else {
      flags |= 4;
    }
    c = *p++;
  }
  --p;
  if (!(flags & 8)) {
    if (endptr)
      p = nptr;
    number = 0;
  } else if ((flags & 4) || (!(flags & 1) && (((flags & 2) && (number < INT32_MIN)) || (!(flags & 2) && (number > INT32_MAX))))) {
    errno = ERANGE;
    if (flags & 1) {
      number = UINT32_MAX;
    } else if (flags & 2) {
      number = INT32_MIN;
    } else {
      number = INT32_MAX;
    }
  }
  if (endptr)
    *endptr = (char *)p;
  if (flags & 2)
    number = (unsigned long)(-(long)number);
  return number;
}
```