user: 请将这段汇编代码片段转换成等效的C代码:

```asm
<lubksb>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %rdi,-0x28(%rbp)
  mov    %rsi,-0x30(%rbp)
  mov    %edx,-0x34(%rbp)
  mov    %rcx,-0x40(%rbp)
  movl   $0x0,-0x14(%rbp)
  movl   $0x1,-0x18(%rbp)
  jmp    L60
L13:
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  mov    %eax,-0xc(%rbp)
  mov    -0xc(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  movsd  %xmm0,-0x8(%rbp)
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rax,%rdx
  mov    -0xc(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rcx
  mov    -0x30(%rbp),%rax
  add    %rcx,%rax
  movsd  (%rdx),%xmm0
  movsd  %xmm0,(%rax)
  cmpl   $0x0,-0x14(%rbp)
  je     L23
  mov    -0x14(%rbp),%eax
  mov    %eax,-0x10(%rbp)
  jmp    L31
L96:
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x10(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm0,%xmm1
  movsd  -0x8(%rbp),%xmm0
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x8(%rbp)
  addl   $0x1,-0x10(%rbp)
L31:
  mov    -0x18(%rbp),%eax
  cmp    -0x10(%rbp),%eax
  jg     L96
  jmp    L114
L23:
  pxor   %xmm0,%xmm0
  ucomisd -0x8(%rbp),%xmm0
  jp     L85
  pxor   %xmm0,%xmm0
  ucomisd -0x8(%rbp),%xmm0
  je     L114
L85:
  mov    -0x18(%rbp),%eax
  mov    %eax,-0x14(%rbp)
L114:
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x8(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x18(%rbp)
L60:
  mov    -0x18(%rbp),%eax
  cmp    -0x34(%rbp),%eax
  jle    L13
  mov    -0x34(%rbp),%eax
  mov    %eax,-0x18(%rbp)
  jmp    L10
L115:
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  movsd  %xmm0,-0x8(%rbp)
  mov    -0x18(%rbp),%eax
  add    $0x1,%eax
  mov    %eax,-0x10(%rbp)
  jmp    L58
L84:
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x10(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  mov    -0x10(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm0,%xmm1
  movsd  -0x8(%rbp),%xmm0
  subsd  %xmm1,%xmm0
  movsd  %xmm0,-0x8(%rbp)
  addl   $0x1,-0x10(%rbp)
L58:
  mov    -0x10(%rbp),%eax
  cmp    -0x34(%rbp),%eax
  jle    L84
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x18(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x8(%rbp),%xmm0
  divsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  subl   $0x1,-0x18(%rbp)
L10:
  cmpl   $0x0,-0x18(%rbp)
  jg     L115
  nop
  nop
  pop    %rbp
  ret
```

assistant: ```c
void lubksb(double **A, double *b, int n, int *indx) {
  int i, ii = 0, ip, j;
  double sum;
  for (i = 1; i <= n; i++) {
    ip = indx[i];
    sum = b[ip];
    b[ip] = b[i];
    if (ii)
      for (j = ii; j <= i - 1; j++)
        sum -= A[i][j] * b[j];
    else if (sum)
      ii = i;
    b[i] = sum;
  }
  for (i = n; i >= 1; i--) {
    sum = b[i];
    for (j = i + 1; j <= n; j++)
      sum -= A[i][j] * b[j];
    b[i] = sum / A[i][i];
  }
}
```