user: 提供的汇编代码用C语言表示会是什么样子：

```asm
<bcd_valid>:
  endbr64
  movzbl (%rdi),%edx
  xor    %r8d,%r8d
  mov    %edx,%ecx
  and    $0xf,%ecx
  cmp    $0x9,%cl
  jg     L195
  mov    %rdi,%rax
  mov    %edx,%edi
  shr    $0x4,%dil
  cmp    $0x9f,%dl
  ja     L195
  movzbl 0x1(%rax),%edx
  mov    %edx,%esi
  and    $0xf,%esi
  cmp    $0x9,%sil
  jg     L195
  mov    %edx,%r9d
  shr    $0x4,%r9b
  cmp    $0x9f,%dl
  ja     L195
  movzbl 0x2(%rax),%r10d
  mov    %r10d,%edx
  and    $0xf,%edx
  cmp    $0x9,%dl
  jg     L195
  mov    %r10d,%r11d
  shr    $0x4,%r11b
  cmp    $0x9f,%r10b
  ja     L195
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  movzbl 0x3(%rax),%ebx
  mov    %ebx,%r10d
  and    $0xf,%r10d
  cmp    $0x9,%r10b
  jg     L67
  mov    %ebx,%ebp
  shr    $0x4,%bpl
  cmp    $0x9f,%bl
  ja     L67
  movzbl 0x4(%rax),%r13d
  mov    %r13d,%ebx
  and    $0xf,%ebx
  cmp    $0x9,%bl
  jg     L67
  mov    %r13d,%r12d
  shr    $0x4,%r12b
  cmp    $0x9f,%r13b
  ja     L67
  movzbl 0x5(%rax),%eax
  mov    %eax,%r13d
  and    $0xf,%r13d
  cmp    $0x9,%r13b
  jg     L67
  mov    %eax,%r14d
  shr    $0x4,%r14b
  cmp    $0x9f,%al
  ja     L67
  movzbl %dil,%edi
  movsbl %cl,%eax
  movzbl %r9b,%r9d
  movsbl %sil,%esi
  lea    (%rdi,%rdi,4),%edi
  lea    (%rax,%rdi,2),%eax
  cmp    $0x17,%eax
  lea    (%r9,%r9,4),%eax
  lea    (%rsi,%rax,2),%eax
  setg   %cl
  cmp    $0x3b,%eax
  setg   %al
  or     %cl,%al
  jne    L133
  movzbl %r11b,%r11d
  movsbl %dl,%edx
  lea    (%r11,%r11,4),%eax
  lea    (%rdx,%rax,2),%eax
  cmp    $0x3c,%eax
  jg     L133
  movzbl %r12b,%r12d
  movsbl %bl,%ebx
  lea    (%r12,%r12,4),%eax
  lea    (%rbx,%rax,2),%edx
  lea    -0x1(%rdx),%eax
  cmp    $0xb,%eax
  ja     L67
  movzbl %bpl,%ebp
  movsbl %r10b,%r10d
  lea    0x0(%rbp,%rbp,4),%eax
  lea    (%r10,%rax,2),%r8d
  test   %r8d,%r8d
  je     L67
  cmp    $0x1c,%r8d
  jle    L27
  movzbl %r14b,%eax
  movsbl %r13b,%r13d
  imul   $0xa,%eax,%eax
  add    %r13d,%eax
  je     L60
  test   $0x3,%al
  jne    L143
L60:
  cmp    $0x1d,%r8d
  je     L27
L143:
  cmp    $0x2,%edx
  je     L16
  cmp    $0x1e,%r8d
  jg     L16
L27:
  mov    $0x1,%r8d
L67:
  pop    %rbx
  mov    %r8d,%eax
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  ret
  nopw   0x0(%rax,%rax,1)
L195:
  mov    %r8d,%eax
  ret
L133:
  xor    %r8d,%r8d
  jmp    L67
L16:
  mov    %edx,%eax
  sar    $0x3,%eax
  xor    %edx,%eax
  not    %eax
  and    $0x1,%eax
  cmp    $0x1f,%r8d
  setg   %dl
  or     %edx,%eax
  xor    $0x1,%eax
  movzbl %al,%r8d
  jmp    L67
```

assistant: ```c
int bcd_valid(const char *bcd) {
  int a, b, c;
  if (!((((bcd[0]) & 15) < 10 && (((bcd[0]) >> 4) & 15) < 10) && (((bcd[1]) & 15) < 10 && (((bcd[1]) >> 4) & 15) < 10) && (((bcd[2]) & 15) < 10 && (((bcd[2]) >> 4) & 15) < 10) && (((bcd[3]) & 15) < 10 && (((bcd[3]) >> 4) & 15) < 10) && (((bcd[4]) & 15) < 10 && (((bcd[4]) >> 4) & 15) < 10) && (((bcd[5]) & 15) < 10 && (((bcd[5]) >> 4) & 15) < 10)))
    return 0;
  a = (((bcd[0]) & 15) + (((bcd[0]) >> 4) & 15) * 10);
  b = (((bcd[1]) & 15) + (((bcd[1]) >> 4) & 15) * 10);
  c = (((bcd[2]) & 15) + (((bcd[2]) >> 4) & 15) * 10);
  if (a > 23 || b > 59 || c > 60)
    return 0;
  a = (((bcd[3]) & 15) + (((bcd[3]) >> 4) & 15) * 10);
  b = (((bcd[4]) & 15) + (((bcd[4]) >> 4) & 15) * 10);
  c = (((bcd[5]) & 15) + (((bcd[5]) >> 4) & 15) * 10);
  if (b < 1 || b > 12)
    return 0;
  if (!(1 <= a && (a <= 28 || (((c) % 400 == 0 || ((c) % 4 == 0 && (c) % 100 != 0)) && a <= 29) || (b != 2 && a <= 30) || (((((b) >> 3) ^ (b)) & 1) && a <= 31))))
    return 0;
  return 1;
}
```