user: 请从给定的汇编指令推导出C源代码:

```asm
<svbksbd>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x50,%rsp
  mov    %rdi,-0x28(%rbp)
  mov    %rsi,-0x30(%rbp)
  mov    %rdx,-0x38(%rbp)
  mov    %ecx,-0x3c(%rbp)
  mov    %r8d,-0x40(%rbp)
  mov    %r9,-0x48(%rbp)
  mov    -0x40(%rbp),%eax
  mov    %eax,%esi
  mov    $0x1,%edi
  call   <dvector@plt>
  mov    %rax,-0x8(%rbp)
  movl   $0x1,-0x18(%rbp)
  jmp    L66
L16:
  pxor   %xmm0,%xmm0
  movsd  %xmm0,-0x10(%rbp)
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  pxor   %xmm1,%xmm1
  ucomisd %xmm1,%xmm0
  jp     L73
  pxor   %xmm1,%xmm1
  ucomisd %xmm1,%xmm0
  je     L78
L73:
  movl   $0x1,-0x14(%rbp)
  jmp    L75
L13:
  mov    -0x14(%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    -0x14(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm1,%xmm0
  movsd  -0x10(%rbp),%xmm1
  addsd  %xmm1,%xmm0
  movsd  %xmm0,-0x10(%rbp)
  addl   $0x1,-0x14(%rbp)
L75:
  mov    -0x14(%rbp),%eax
  cmp    -0x3c(%rbp),%eax
  jle    L13
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  movsd  -0x10(%rbp),%xmm0
  divsd  %xmm1,%xmm0
  movsd  %xmm0,-0x10(%rbp)
L78:
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x10(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x18(%rbp)
L66:
  mov    -0x18(%rbp),%eax
  cmp    -0x40(%rbp),%eax
  jle    L16
  movl   $0x1,-0x18(%rbp)
  jmp    L64
L30:
  pxor   %xmm0,%xmm0
  movsd  %xmm0,-0x10(%rbp)
  movl   $0x1,-0x1c(%rbp)
  jmp    L59
L80:
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%rdx
  mov    -0x1c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  mov    -0x1c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x8(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm1,%xmm0
  movsd  -0x10(%rbp),%xmm1
  addsd  %xmm1,%xmm0
  movsd  %xmm0,-0x10(%rbp)
  addl   $0x1,-0x1c(%rbp)
L59:
  mov    -0x1c(%rbp),%eax
  cmp    -0x40(%rbp),%eax
  jle    L80
  mov    -0x18(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  movsd  -0x10(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x18(%rbp)
L64:
  mov    -0x18(%rbp),%eax
  cmp    -0x40(%rbp),%eax
  jle    L30
  mov    -0x8(%rbp),%rax
  mov    $0x1,%esi
  mov    %rax,%rdi
  call   <free_dvector@plt>
  nop
  leave
  ret
```

assistant: ```c
void svbksbd(double **u, double w[], double **v, int m, int n, double b[], double x[]) {
  int jj, j, i;
  double s, *tmp;
  tmp = dvector(1, n);
  for (j = 1; j <= n; j++) {
    s = 0.0;
    if (w[j]) {
      for (i = 1; i <= m; i++)
        s += u[i][j] * b[i];
      s /= w[j];
    }
    tmp[j] = s;
  }
  for (j = 1; j <= n; j++) {
    s = 0.0;
    for (jj = 1; jj <= n; jj++)
      s += v[j][jj] * tmp[jj];
    x[j] = s;
  }
  free_dvector(tmp, 1);
}
```