user: What is the c source code of the assembly code below?

```asm
<interpolate_product_double>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %rbx
  sub    $0x78,%rsp
  mov    %rdi,-0x68(%rbp)
  mov    %rsi,-0x70(%rbp)
  mov    %edx,-0x74(%rbp)
  mov    %ecx,-0x78(%rbp)
  mov    %r8,-0x80(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x18(%rbp)
  xor    %eax,%eax
  mov    $0x0,%eax
  call   <_mm_setzero_pd@plt>
  mov    %rax,-0x50(%rbp)
  mov    $0x0,%eax
  call   <_mm_setzero_pd@plt>
  mov    %rax,-0x48(%rbp)
  mov    -0x80(%rbp),%rax
  mov    %rax,%rdi
  call   <_mm_loadu_ps@plt>
  mov    %rax,-0x40(%rbp)
  mov    -0x40(%rbp),%rax
  mov    %rax,%rdi
  call   <_mm_cvtps_pd@plt>
  mov    %rax,-0x38(%rbp)
  mov    -0x40(%rbp),%rdx
  mov    -0x40(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <_mm_movehl_ps@plt>
  mov    %rax,%rdi
  call   <_mm_cvtps_pd@plt>
  mov    %rax,-0x30(%rbp)
  movl   $0x0,-0x5c(%rbp)
  jmp    L11
L25:
  mov    -0x5c(%rbp),%eax
  imul   -0x78(%rbp),%eax
  mov    %eax,%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x70(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdi
  call   <_mm_loadu_ps@plt>
  mov    %rax,%rbx
  mov    -0x5c(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x68(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdi
  call   <_mm_load1_ps@plt>
  mov    %rbx,%rsi
  mov    %eax,%edi
  call   <_mm_mul_ps@plt>
  mov    %rax,-0x20(%rbp)
  mov    -0x20(%rbp),%rax
  mov    %rax,%rdi
  call   <_mm_cvtps_pd@plt>
  mov    %rax,%rdx
  mov    -0x50(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <_mm_add_pd@plt>
  mov    %rax,-0x50(%rbp)
  mov    -0x20(%rbp),%rdx
  mov    -0x20(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <_mm_movehl_ps@plt>
  mov    %rax,%rdi
  call   <_mm_cvtps_pd@plt>
  mov    %rax,%rdx
  mov    -0x48(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <_mm_add_pd@plt>
  mov    %rax,-0x48(%rbp)
  mov    -0x5c(%rbp),%eax
  add    $0x1,%eax
  imul   -0x78(%rbp),%eax
  mov    %eax,%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x70(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdi
  call   <_mm_loadu_ps@plt>
  mov    %rax,%rbx
  mov    -0x5c(%rbp),%eax
  cltq
  add    $0x1,%rax
  lea    0x0(,%rax,4),%rdx
  mov    -0x68(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,%rdi
  call   <_mm_load1_ps@plt>
  mov    %rbx,%rsi
  mov    %eax,%edi
  call   <_mm_mul_ps@plt>
  mov    %rax,-0x20(%rbp)
  mov    -0x20(%rbp),%rax
  mov    %rax,%rdi
  call   <_mm_cvtps_pd@plt>
  mov    %rax,%rdx
  mov    -0x50(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <_mm_add_pd@plt>
  mov    %rax,-0x50(%rbp)
  mov    -0x20(%rbp),%rdx
  mov    -0x20(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <_mm_movehl_ps@plt>
  mov    %rax,%rdi
  call   <_mm_cvtps_pd@plt>
  mov    %rax,%rdx
  mov    -0x48(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <_mm_add_pd@plt>
  mov    %rax,-0x48(%rbp)
  addl   $0x2,-0x5c(%rbp)
L11:
  mov    -0x5c(%rbp),%eax
  cmp    %eax,-0x74(%rbp)
  ja     L25
  mov    -0x50(%rbp),%rdx
  mov    -0x38(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <_mm_mul_pd@plt>
  mov    %rax,-0x50(%rbp)
  mov    -0x48(%rbp),%rdx
  mov    -0x30(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <_mm_mul_pd@plt>
  mov    %rax,-0x48(%rbp)
  mov    -0x48(%rbp),%rdx
  mov    -0x50(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <_mm_add_pd@plt>
  mov    %rax,-0x28(%rbp)
  mov    -0x28(%rbp),%rdx
  mov    -0x28(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <_mm_movehl_ps@plt>
  mov    %rax,%rdx
  mov    -0x28(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <_mm_add_sd@plt>
  mov    %rax,-0x28(%rbp)
  mov    -0x28(%rbp),%rdx
  lea    -0x58(%rbp),%rax
  mov    %rdx,%rsi
  mov    %rax,%rdi
  call   <_mm_store_sd@plt>
  movsd  -0x58(%rbp),%xmm0
  movq   %xmm0,%rax
  mov    -0x18(%rbp),%rdx
  sub    %fs:0x28,%rdx
  je     L26
  call   <__stack_chk_fail@plt>
L26:
  movq   %rax,%xmm0
  mov    -0x8(%rbp),%rbx
  leave
  ret
```

assistant: ```c
double interpolate_product_double(const float *a, const float *b, unsigned int len, const unsigned int oversample, float *frac) {
  int i;
  double ret;
  __m128d sum;
  __m128d sum1 = _mm_setzero_pd();
  __m128d sum2 = _mm_setzero_pd();
  __m128 f = _mm_loadu_ps(frac);
  __m128d f1 = _mm_cvtps_pd(f);
  __m128d f2 = _mm_cvtps_pd(_mm_movehl_ps(f, f));
  __m128 t;
  for (i = 0; i < len; i += 2) {
    t = _mm_mul_ps(_mm_load1_ps(a + i), _mm_loadu_ps(b + i * oversample));
    sum1 = _mm_add_pd(sum1, _mm_cvtps_pd(t));
    sum2 = _mm_add_pd(sum2, _mm_cvtps_pd(_mm_movehl_ps(t, t)));
    t = _mm_mul_ps(_mm_load1_ps(a + i + 1), _mm_loadu_ps(b + (i + 1) * oversample));
    sum1 = _mm_add_pd(sum1, _mm_cvtps_pd(t));
    sum2 = _mm_add_pd(sum2, _mm_cvtps_pd(_mm_movehl_ps(t, t)));
  }
  sum1 = _mm_mul_pd(f1, sum1);
  sum2 = _mm_mul_pd(f2, sum2);
  sum = _mm_add_pd(sum1, sum2);
  sum = _mm_add_sd(sum, (__m128d)_mm_movehl_ps((__m128)sum, (__m128)sum));
  _mm_store_sd(&ret, sum);
  return ret;
}
```