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

```asm
<highbd_transpose6x6_sse2>:
  endbr64
  push   %r15
  mov    %rdi,%r10
  mov    %rsi,%r11
  mov    %rcx,%r15
  push   %r14
  mov    %rdx,%r14
  push   %r13
  push   %r12
  push   %rbp
  mov    %r8,%rbp
  push   %rbx
  mov    %r9,%rbx
  sub    $0x28,%rsp
  mov    (%rsi),%esi
  mov    (%rdi),%edi
  mov    %r11,0x18(%rsp)
  mov    %r10,0x10(%rsp)
  call   <_mm_unpacklo_epi16@plt>
  mov    (%r15),%esi
  mov    (%r14),%edi
  mov    %eax,%r13d
  call   <_mm_unpacklo_epi16@plt>
  mov    (%rbx),%esi
  mov    0x0(%rbp),%edi
  mov    %rbp,(%rsp)
  mov    %eax,%r12d
  call   <_mm_unpacklo_epi16@plt>
  mov    %r12d,%esi
  mov    %r13d,%edi
  mov    %eax,%ebp
  call   <_mm_unpacklo_epi32@plt>
  mov    %ebp,%esi
  mov    %eax,%edi
  mov    %eax,0xc(%rsp)
  call   <_mm_unpacklo_epi64@plt>
  mov    0x60(%rsp),%rdx
  mov    %ebp,%edi
  mov    $0x4,%esi
  mov    %eax,(%rdx)
  call   <_mm_srli_si128@plt>
  mov    0xc(%rsp),%edi
  mov    %eax,%esi
  call   <_mm_unpackhi_epi64@plt>
  mov    0x68(%rsp),%rdx
  mov    %r12d,%esi
  mov    %r13d,%edi
  mov    %eax,(%rdx)
  call   <_mm_unpackhi_epi32@plt>
  mov    %ebp,%edi
  mov    $0x8,%esi
  mov    %eax,%r13d
  call   <_mm_srli_si128@plt>
  mov    %r13d,%edi
  mov    %eax,%esi
  call   <_mm_unpacklo_epi64@plt>
  mov    0x70(%rsp),%rdx
  mov    0x18(%rsp),%r11
  mov    0x10(%rsp),%r10
  mov    %eax,(%rdx)
  mov    (%r11),%esi
  mov    (%r10),%edi
  call   <_mm_unpackhi_epi16@plt>
  mov    (%r15),%esi
  mov    (%r14),%edi
  mov    %eax,0xc(%rsp)
  call   <_mm_unpackhi_epi16@plt>
  mov    (%rbx),%esi
  mov    %eax,%r14d
  mov    (%rsp),%rax
  mov    (%rax),%edi
  call   <_mm_unpackhi_epi16@plt>
  mov    %ebp,%edi
  mov    $0x4,%esi
  mov    %eax,%r12d
  call   <_mm_srli_si128@plt>
  mov    %r13d,%edi
  mov    %eax,%esi
  call   <_mm_unpackhi_epi64@plt>
  mov    0x78(%rsp),%rdx
  mov    0xc(%rsp),%edi
  mov    %r14d,%esi
  mov    %eax,(%rdx)
  call   <_mm_unpacklo_epi32@plt>
  mov    %r12d,%esi
  mov    %eax,%edi
  mov    %eax,%ebp
  call   <_mm_unpacklo_epi64@plt>
  mov    0x80(%rsp),%rdx
  mov    %r12d,%edi
  mov    $0x4,%esi
  mov    %eax,(%rdx)
  call   <_mm_slli_si128@plt>
  mov    %ebp,%edi
  mov    %eax,%esi
  call   <_mm_unpackhi_epi64@plt>
  mov    0x88(%rsp),%rdx
  mov    %eax,(%rdx)
  add    $0x28,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
void highbd_transpose6x6_sse2(__m128i *x0, __m128i *x1, __m128i *x2, __m128i *x3, __m128i *x4, __m128i *x5, __m128i *d0, __m128i *d1, __m128i *d2, __m128i *d3, __m128i *d4, __m128i *d5) {
  __m128i w0, w1, w2, w3, w4, w5, ww0;
  w0 = _mm_unpacklo_epi16(*x0, *x1);
  w1 = _mm_unpacklo_epi16(*x2, *x3);
  w2 = _mm_unpacklo_epi16(*x4, *x5);
  ww0 = _mm_unpacklo_epi32(w0, w1);
  *d0 = _mm_unpacklo_epi64(ww0, w2);
  *d1 = _mm_unpackhi_epi64(ww0, _mm_srli_si128(w2, 4));
  ww0 = _mm_unpackhi_epi32(w0, w1);
  *d2 = _mm_unpacklo_epi64(ww0, _mm_srli_si128(w2, 8));
  w3 = _mm_unpackhi_epi16(*x0, *x1);
  w4 = _mm_unpackhi_epi16(*x2, *x3);
  w5 = _mm_unpackhi_epi16(*x4, *x5);
  *d3 = _mm_unpackhi_epi64(ww0, _mm_srli_si128(w2, 4));
  ww0 = _mm_unpacklo_epi32(w3, w4);
  *d4 = _mm_unpacklo_epi64(ww0, w5);
  *d5 = _mm_unpackhi_epi64(ww0, _mm_slli_si128(w5, 4));
}
```