user: 提供的汇编代码用C语言表示会是什么样子：

```asm
<bn_sub_words>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x40,%rsp
  mov    %rdi,-0x28(%rbp)
  mov    %rsi,-0x30(%rbp)
  mov    %rdx,-0x38(%rbp)
  mov    %ecx,-0x3c(%rbp)
  movl   $0x0,-0x14(%rbp)
  mov    -0x3c(%rbp),%eax
  not    %eax
  shr    $0x1f,%eax
  movzbl %al,%eax
  mov    %eax,%edi
  call   <assert@plt>
  cmpl   $0x0,-0x3c(%rbp)
  jg     L132
  mov    $0x0,%eax
  jmp    L38
L132:
  mov    -0x30(%rbp),%rax
  mov    (%rax),%rax
  mov    %rax,-0x10(%rbp)
  mov    -0x38(%rbp),%rax
  mov    (%rax),%rax
  mov    %rax,-0x8(%rbp)
  mov    -0x10(%rbp),%rax
  sub    -0x8(%rbp),%rax
  mov    -0x14(%rbp),%edx
  movslq %edx,%rdx
  sub    %rdx,%rax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  mov    %rdx,(%rax)
  mov    -0x10(%rbp),%rax
  cmp    -0x8(%rbp),%rax
  je     L120
  mov    -0x10(%rbp),%rax
  cmp    -0x8(%rbp),%rax
  setb   %al
  movzbl %al,%eax
  mov    %eax,-0x14(%rbp)
L120:
  subl   $0x1,-0x3c(%rbp)
  cmpl   $0x0,-0x3c(%rbp)
  jle    L14
  mov    -0x30(%rbp),%rax
  add    $0x8,%rax
  mov    (%rax),%rax
  mov    %rax,-0x10(%rbp)
  mov    -0x38(%rbp),%rax
  add    $0x8,%rax
  mov    (%rax),%rax
  mov    %rax,-0x8(%rbp)
  mov    -0x10(%rbp),%rax
  sub    -0x8(%rbp),%rax
  mov    -0x14(%rbp),%edx
  movslq %edx,%rdx
  sub    %rdx,%rax
  mov    %rax,%rcx
  mov    -0x28(%rbp),%rax
  add    $0x8,%rax
  mov    %ecx,%edx
  mov    %rdx,(%rax)
  mov    -0x10(%rbp),%rax
  cmp    -0x8(%rbp),%rax
  je     L21
  mov    -0x10(%rbp),%rax
  cmp    -0x8(%rbp),%rax
  setb   %al
  movzbl %al,%eax
  mov    %eax,-0x14(%rbp)
L21:
  subl   $0x1,-0x3c(%rbp)
  cmpl   $0x0,-0x3c(%rbp)
  jle    L0
  mov    -0x30(%rbp),%rax
  add    $0x10,%rax
  mov    (%rax),%rax
  mov    %rax,-0x10(%rbp)
  mov    -0x38(%rbp),%rax
  add    $0x10,%rax
  mov    (%rax),%rax
  mov    %rax,-0x8(%rbp)
  mov    -0x10(%rbp),%rax
  sub    -0x8(%rbp),%rax
  mov    -0x14(%rbp),%edx
  movslq %edx,%rdx
  sub    %rdx,%rax
  mov    %rax,%rcx
  mov    -0x28(%rbp),%rax
  add    $0x10,%rax
  mov    %ecx,%edx
  mov    %rdx,(%rax)
  mov    -0x10(%rbp),%rax
  cmp    -0x8(%rbp),%rax
  je     L39
  mov    -0x10(%rbp),%rax
  cmp    -0x8(%rbp),%rax
  setb   %al
  movzbl %al,%eax
  mov    %eax,-0x14(%rbp)
L39:
  subl   $0x1,-0x3c(%rbp)
  cmpl   $0x0,-0x3c(%rbp)
  jle    L13
  mov    -0x30(%rbp),%rax
  add    $0x18,%rax
  mov    (%rax),%rax
  mov    %rax,-0x10(%rbp)
  mov    -0x38(%rbp),%rax
  add    $0x18,%rax
  mov    (%rax),%rax
  mov    %rax,-0x8(%rbp)
  mov    -0x10(%rbp),%rax
  sub    -0x8(%rbp),%rax
  mov    -0x14(%rbp),%edx
  movslq %edx,%rdx
  sub    %rdx,%rax
  mov    %rax,%rcx
  mov    -0x28(%rbp),%rax
  add    $0x18,%rax
  mov    %ecx,%edx
  mov    %rdx,(%rax)
  mov    -0x10(%rbp),%rax
  cmp    -0x8(%rbp),%rax
  je     L55
  mov    -0x10(%rbp),%rax
  cmp    -0x8(%rbp),%rax
  setb   %al
  movzbl %al,%eax
  mov    %eax,-0x14(%rbp)
L55:
  subl   $0x1,-0x3c(%rbp)
  cmpl   $0x0,-0x3c(%rbp)
  jle    L54
  addq   $0x20,-0x30(%rbp)
  addq   $0x20,-0x38(%rbp)
  addq   $0x20,-0x28(%rbp)
  jmp    L132
L14:
  nop
  jmp    L11
L0:
  nop
  jmp    L11
L13:
  nop
  jmp    L11
L54:
  nop
L11:
  mov    -0x14(%rbp),%eax
  cltq
L38:
  leave
  ret
```

assistant: ```c
unsigned long bn_sub_words(unsigned long *r, const unsigned long *a, const unsigned long *b, int n) {
  unsigned long t1, t2;
  int c = 0;
  assert(n >= 0);
  if (n <= 0)
    return ((unsigned long)0);
  for (;;) {
    t1 = a[0];
    t2 = b[0];
    r[0] = (t1 - t2 - c) & (0xffffffffL);
    if (t1 != t2)
      c = (t1 < t2);
    if (--n <= 0)
      break;
    t1 = a[1];
    t2 = b[1];
    r[1] = (t1 - t2 - c) & (0xffffffffL);
    if (t1 != t2)
      c = (t1 < t2);
    if (--n <= 0)
      break;
    t1 = a[2];
    t2 = b[2];
    r[2] = (t1 - t2 - c) & (0xffffffffL);
    if (t1 != t2)
      c = (t1 < t2);
    if (--n <= 0)
      break;
    t1 = a[3];
    t2 = b[3];
    r[3] = (t1 - t2 - c) & (0xffffffffL);
    if (t1 != t2)
      c = (t1 < t2);
    if (--n <= 0)
      break;
    a += 4;
    b += 4;
    r += 4;
  }
  return (c);
}
```