user: Demonstrate the C code that generates the assembly output below:

```asm
<alphanum_cmp>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x8,%rsp
  cmpb   $0x0,(%rdi)
  movzbl (%rsi),%ebx
  je     L213
  mov    %rdi,%r12
  mov    %rsi,%r13
  xor    %eax,%eax
L94:
  test   %bl,%bl
  je     L184
  movsbl (%r12),%edi
  test   %eax,%eax
  je     L221
  xor    %ebp,%ebp
  test   %dil,%dil
  jne    L135
  jmp    L71
  nopl   0x0(%rax)
L25:
  movsbq (%r12),%rax
  movsbl 0x1(%r12),%edi
  lea    0x0(%rbp,%rbp,4),%rdx
  add    $0x1,%r12
  lea    -0x30(%rax,%rdx,2),%rbp
  test   %dil,%dil
  je     L235
L135:
  call   <alphanum_isdigit@plt>
  test   %eax,%eax
  jne    L25
L235:
  movzbl 0x0(%r13),%ebx
  test   %bl,%bl
  je     L203
L71:
  xor    %r14d,%r14d
  jmp    L1
  nopl   (%rax)
L148:
  movsbq 0x0(%r13),%rax
  movzbl 0x1(%r13),%ebx
  lea    (%r14,%r14,4),%rdx
  add    $0x1,%r13
  lea    -0x30(%rax,%rdx,2),%r14
  test   %bl,%bl
  je     L237
L1:
  movsbl %bl,%edi
  call   <alphanum_isdigit@plt>
  test   %eax,%eax
  jne    L148
L237:
  sub    %r14,%rbp
L203:
  test   %rbp,%rbp
  jne    L111
  movzbl (%r12),%edx
  movzbl 0x0(%r13),%ebx
  xor    %eax,%eax
L88:
  test   %dl,%dl
  jne    L94
  nopw   0x0(%rax,%rax,1)
L213:
  test   %bl,%bl
  jne    L129
  xor    %eax,%eax
L139:
  add    $0x8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   (%rax)
L221:
  test   %dil,%dil
  jne    L246
  jmp    L129
  nop
L34:
  test   %eax,%eax
  jne    L184
  mov    %r14d,%edi
  call   <toupper@plt>
  mov    %ebp,%edi
  mov    %eax,%ebx
  call   <toupper@plt>
  movsbl %al,%edx
  movsbl %bl,%eax
  sub    %edx,%eax
  jne    L139
  movzbl 0x1(%r12),%edi
  add    $0x1,%r12
  add    $0x1,%r13
  movzbl 0x0(%r13),%ebx
  test   %dil,%dil
  je     L213
  test   %bl,%bl
  je     L184
L246:
  movsbl %dil,%r14d
  movsbl %bl,%ebp
  mov    %r14d,%edi
  call   <alphanum_isdigit@plt>
  mov    %ebp,%edi
  mov    %eax,%r15d
  call   <alphanum_isdigit@plt>
  test   %r15d,%r15d
  je     L34
  test   %eax,%eax
  jne    L108
  test   %r15d,%r15d
  je     L34
L129:
  add    $0x8,%rsp
  mov    $0xffffffff,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  cs nopw 0x0(%rax,%rax,1)
L184:
  add    $0x8,%rsp
  mov    $0x1,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax)
L108:
  movzbl (%r12),%edx
  movzbl 0x0(%r13),%ebx
  mov    $0x1,%eax
  jmp    L88
L111:
  mov    %ebp,%eax
  jmp    L139
```

assistant: ```c
int alphanum_cmp(const char *l, const char *r) {
  enum mode_t { STRING, NUMBER } mode = STRING;
  while (*l && *r) {
    if (mode == STRING) {
      char l_char, r_char;
      while ((l_char = *l) && (r_char = *r)) {
        const int l_digit = alphanum_isdigit(l_char);
        const int r_digit = alphanum_isdigit(r_char);
        if (l_digit && r_digit) {
          mode = NUMBER;
          break;
        }
        if (l_digit)
          return -1;
        if (r_digit)
          return +1;
        l_char = toupper(l_char);
        r_char = toupper(r_char);
        const int diff = l_char - r_char;
        if (diff != 0)
          return diff;
        ++l;
        ++r;
      }
    } else {
      unsigned long l_int = 0;
      while (*l && alphanum_isdigit(*l)) {
        l_int = l_int * 10 + *l - '0';
        ++l;
      }
      unsigned long r_int = 0;
      while (*r && alphanum_isdigit(*r)) {
        r_int = r_int * 10 + *r - '0';
        ++r;
      }
      const long diff = l_int - r_int;
      if (diff != 0)
        return diff;
      mode = STRING;
    }
  }
  if (*r)
    return -1;
  if (*l)
    return +1;
  return 0;
}
```