user: 这段汇编代码用C语言表示是什么样的:

```asm
<ezxml_str2utf8>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x50,%rsp
  mov    %rdi,-0x48(%rbp)
  mov    %rsi,-0x50(%rbp)
  movq   $0x0,-0x28(%rbp)
  mov    -0x50(%rbp),%rax
  mov    (%rax),%rax
  mov    %rax,-0x18(%rbp)
  mov    -0x48(%rbp),%rax
  mov    (%rax),%rax
  movzbl (%rax),%eax
  cmp    $0xfe,%al
  je     L23
  mov    -0x48(%rbp),%rax
  mov    (%rax),%rax
  movzbl (%rax),%eax
  cmp    $0xff,%al
  jne    L12
  mov    $0x0,%eax
  jmp    L204
L12:
  mov    $0xffffffff,%eax
  jmp    L204
L23:
  mov    $0x1,%eax
L204:
  mov    %eax,-0x34(%rbp)
  cmpl   $0xffffffff,-0x34(%rbp)
  jne    L195
  mov    $0x0,%eax
  jmp    L17
L195:
  mov    -0x18(%rbp),%rax
  mov    %rax,%rdi
  call   <malloc@plt>
  mov    %rax,-0x30(%rbp)
  movq   $0x2,-0x20(%rbp)
  jmp    L206
L51:
  cmpl   $0x0,-0x34(%rbp)
  je     L150
  mov    -0x48(%rbp),%rax
  mov    (%rax),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  shl    $0x8,%eax
  movzwl %ax,%edx
  mov    -0x48(%rbp),%rax
  mov    (%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    $0x1,%rax
  add    %rcx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  movzbl %al,%eax
  or     %edx,%eax
  cltq
  jmp    L182
L150:
  mov    -0x48(%rbp),%rax
  mov    (%rax),%rdx
  mov    -0x20(%rbp),%rax
  add    $0x1,%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  shl    $0x8,%eax
  movzwl %ax,%edx
  mov    -0x48(%rbp),%rax
  mov    (%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    %rcx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  movzbl %al,%eax
  or     %edx,%eax
  cltq
L182:
  mov    %rax,-0x10(%rbp)
  cmpq   $0xd7ff,-0x10(%rbp)
  jle    L221
  cmpq   $0xdfff,-0x10(%rbp)
  jg     L221
  addq   $0x2,-0x20(%rbp)
  mov    -0x50(%rbp),%rax
  mov    (%rax),%rax
  sub    $0x1,%rax
  cmp    %rax,-0x20(%rbp)
  jae    L221
  cmpl   $0x0,-0x34(%rbp)
  je     L193
  mov    -0x48(%rbp),%rax
  mov    (%rax),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  shl    $0x8,%eax
  movzwl %ax,%edx
  mov    -0x48(%rbp),%rax
  mov    (%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    $0x1,%rax
  add    %rcx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  movzbl %al,%eax
  or     %edx,%eax
  cltq
  jmp    L38
L193:
  mov    -0x48(%rbp),%rax
  mov    (%rax),%rdx
  mov    -0x20(%rbp),%rax
  add    $0x1,%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  shl    $0x8,%eax
  movzwl %ax,%edx
  mov    -0x48(%rbp),%rax
  mov    (%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    %rcx,%rax
  movzbl (%rax),%eax
  movsbl %al,%eax
  movzbl %al,%eax
  or     %edx,%eax
  cltq
L38:
  mov    %rax,-0x8(%rbp)
  mov    -0x10(%rbp),%rax
  shl    $0xa,%rax
  and    $0xffc00,%eax
  mov    %rax,%rdx
  mov    -0x8(%rbp),%rax
  and    $0x3ff,%eax
  or     %rdx,%rax
  add    $0x10000,%rax
  mov    %rax,-0x10(%rbp)
  jmp    L221
L71:
  addq   $0x400,-0x18(%rbp)
  mov    -0x18(%rbp),%rdx
  mov    -0x30(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <realloc@plt>
  mov    %rax,-0x30(%rbp)
L221:
  mov    -0x28(%rbp),%rax
  add    $0x6,%rax
  cmp    %rax,-0x18(%rbp)
  jb     L71
  cmpq   $0x7f,-0x10(%rbp)
  jg     L141
  mov    -0x28(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x28(%rbp)
  mov    -0x30(%rbp),%rdx
  add    %rdx,%rax
  mov    -0x10(%rbp),%rdx
  mov    %dl,(%rax)
  jmp    L117
L141:
  movl   $0x0,-0x38(%rbp)
  mov    -0x10(%rbp),%rax
  mov    %rax,-0x8(%rbp)
  jmp    L85
L163:
  addl   $0x1,-0x38(%rbp)
  mov    -0x8(%rbp),%rax
  mov    %rax,%rdx
  shr    $0x3f,%rdx
  add    %rdx,%rax
  sar    %rax
  mov    %rax,-0x8(%rbp)
L85:
  cmpq   $0x0,-0x8(%rbp)
  jne    L163
  mov    -0x38(%rbp),%eax
  sub    $0x2,%eax
  movslq %eax,%rdx
  imul   $0x66666667,%rdx,%rdx
  shr    $0x20,%rdx
  sar    %edx
  sar    $0x1f,%eax
  mov    %eax,%ecx
  mov    %edx,%eax
  sub    %ecx,%eax
  mov    %eax,-0x38(%rbp)
  mov    $0x7,%eax
  sub    -0x38(%rbp),%eax
  mov    $0xff,%edx
  mov    %eax,%ecx
  shl    %cl,%edx
  mov    %edx,%eax
  mov    %eax,%esi
  mov    -0x38(%rbp),%edx
  mov    %edx,%eax
  add    %eax,%eax
  add    %edx,%eax
  add    %eax,%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%rax
  mov    %edx,%ecx
  sar    %cl,%rax
  mov    %eax,%ecx
  mov    -0x28(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x28(%rbp)
  mov    -0x30(%rbp),%rdx
  add    %rdx,%rax
  or     %ecx,%esi
  mov    %esi,%edx
  mov    %dl,(%rax)
  jmp    L75
L152:
  subl   $0x1,-0x38(%rbp)
  mov    -0x38(%rbp),%edx
  mov    %edx,%eax
  add    %eax,%eax
  add    %edx,%eax
  add    %eax,%eax
  mov    %eax,%edx
  mov    -0x10(%rbp),%rax
  mov    %edx,%ecx
  sar    %cl,%rax
  and    $0x3f,%eax
  mov    %eax,%ecx
  mov    -0x28(%rbp),%rax
  lea    0x1(%rax),%rdx
  mov    %rdx,-0x28(%rbp)
  mov    -0x30(%rbp),%rdx
  add    %rdx,%rax
  or     $0xffffff80,%ecx
  mov    %ecx,%edx
  mov    %dl,(%rax)
L75:
  cmpl   $0x0,-0x38(%rbp)
  jne    L152
L117:
  addq   $0x2,-0x20(%rbp)
L206:
  mov    -0x50(%rbp),%rax
  mov    (%rax),%rax
  sub    $0x1,%rax
  cmp    %rax,-0x20(%rbp)
  jb     L51
  mov    -0x50(%rbp),%rax
  mov    -0x28(%rbp),%rdx
  mov    %rdx,(%rax)
  mov    -0x50(%rbp),%rax
  mov    (%rax),%rdx
  mov    -0x30(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <realloc@plt>
  mov    %rax,%rdx
  mov    -0x48(%rbp),%rax
  mov    %rdx,(%rax)
  mov    -0x48(%rbp),%rax
  mov    (%rax),%rax
L17:
  leave
  ret
```

assistant: ```c
char *ezxml_str2utf8(char **s, size_t *len) {
  char *u;
  size_t l = 0, sl, max = *len;
  long c, d;
  int b, be = (**s == '\xFE') ? 1 : (**s == '\xFF') ? 0 : -1;
  if (be == -1)
    return NULL;
  u = (char *)malloc(max);
  for (sl = 2; sl < *len - 1; sl += 2) {
    c = (be) ? (((*s)[sl] & 0xFF) << 8) | ((*s)[sl + 1] & 0xFF) : (((*s)[sl + 1] & 0xFF) << 8) | ((*s)[sl] & 0xFF);
    if (c >= 0xD800 && c <= 0xDFFF && (sl += 2) < *len - 1) {
      d = (be) ? (((*s)[sl] & 0xFF) << 8) | ((*s)[sl + 1] & 0xFF) : (((*s)[sl + 1] & 0xFF) << 8) | ((*s)[sl] & 0xFF);
      c = (((c & 0x3FF) << 10) | (d & 0x3FF)) + 0x10000;
    }
    while (l + 6 > max)
      u = (char *)realloc(u, max += 1024);
    if (c < 0x80)
      u[l++] = (char)c;
    else {
      for (b = 0, d = c; d; d /= 2)
        b++;
      b = (b - 2) / 5;
      u[l++] = (char)((0xFF << (7 - b)) | (c >> (6 * b)));
      while (b)
        u[l++] = 0x80 | ((c >> (6 * --b)) & 0x3F);
    }
  }
  return *s = (char *)realloc(u, *len = l);
}
```