user: 请将这段汇编代码片段转换成等效的C代码:

```asm
<transpose_8bit_8x8>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  mov    %rdi,%rbp
  push   %rbx
  mov    %rsi,%rbx
  sub    $0x18,%rsp
  mov    0x4(%rdi),%esi
  mov    (%rdi),%edi
  call   <_mm_unpacklo_epi8@plt>
  mov    0xc(%rbp),%esi
  mov    0x8(%rbp),%edi
  mov    %eax,%r13d
  call   <_mm_unpacklo_epi8@plt>
  mov    0x14(%rbp),%esi
  mov    0x10(%rbp),%edi
  mov    %eax,0xc(%rsp)
  call   <_mm_unpacklo_epi8@plt>
  mov    0x1c(%rbp),%esi
  mov    0x18(%rbp),%edi
  mov    %eax,%r14d
  call   <_mm_unpacklo_epi8@plt>
  mov    0xc(%rsp),%esi
  mov    %r13d,%edi
  mov    %eax,%r15d
  call   <_mm_unpacklo_epi16@plt>
  mov    0xc(%rsp),%esi
  mov    %r13d,%edi
  mov    %eax,%r12d
  call   <_mm_unpackhi_epi16@plt>
  mov    %r15d,%esi
  mov    %r14d,%edi
  mov    %eax,%ebp
  call   <_mm_unpacklo_epi16@plt>
  mov    %r15d,%esi
  mov    %r14d,%edi
  mov    %eax,%r13d
  call   <_mm_unpackhi_epi16@plt>
  mov    %r13d,%esi
  mov    %r12d,%edi
  mov    %eax,%r15d
  call   <_mm_unpacklo_epi32@plt>
  mov    %r13d,%esi
  mov    %r12d,%edi
  mov    %eax,%r14d
  call   <_mm_unpackhi_epi32@plt>
  mov    %r15d,%esi
  mov    %ebp,%edi
  mov    %eax,%r13d
  call   <_mm_unpacklo_epi32@plt>
  mov    %r15d,%esi
  mov    %ebp,%edi
  mov    %eax,%r12d
  call   <_mm_unpackhi_epi32@plt>
  mov    %r14d,%esi
  mov    %r14d,%edi
  mov    %eax,%ebp
  call   <_mm_unpacklo_epi64@plt>
  mov    %r14d,%esi
  mov    %r14d,%edi
  mov    %eax,(%rbx)
  call   <_mm_unpackhi_epi64@plt>
  mov    %r13d,%esi
  mov    %r13d,%edi
  mov    %eax,0x4(%rbx)
  call   <_mm_unpacklo_epi64@plt>
  mov    %r13d,%esi
  mov    %r13d,%edi
  mov    %eax,0x8(%rbx)
  call   <_mm_unpackhi_epi64@plt>
  mov    %r12d,%esi
  mov    %r12d,%edi
  mov    %eax,0xc(%rbx)
  call   <_mm_unpacklo_epi64@plt>
  mov    %r12d,%esi
  mov    %r12d,%edi
  mov    %eax,0x10(%rbx)
  call   <_mm_unpackhi_epi64@plt>
  mov    %ebp,%esi
  mov    %ebp,%edi
  mov    %eax,0x14(%rbx)
  call   <_mm_unpacklo_epi64@plt>
  mov    %ebp,%esi
  mov    %ebp,%edi
  mov    %eax,0x18(%rbx)
  call   <_mm_unpackhi_epi64@plt>
  mov    %eax,0x1c(%rbx)
  add    $0x18,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
void transpose_8bit_8x8(const __m128i *const in, __m128i *const out) {
  const __m128i a0 = _mm_unpacklo_epi8(in[0], in[1]);
  const __m128i a1 = _mm_unpacklo_epi8(in[2], in[3]);
  const __m128i a2 = _mm_unpacklo_epi8(in[4], in[5]);
  const __m128i a3 = _mm_unpacklo_epi8(in[6], in[7]);
  const __m128i b0 = _mm_unpacklo_epi16(a0, a1);
  const __m128i b1 = _mm_unpackhi_epi16(a0, a1);
  const __m128i b2 = _mm_unpacklo_epi16(a2, a3);
  const __m128i b3 = _mm_unpackhi_epi16(a2, a3);
  const __m128i c0 = _mm_unpacklo_epi32(b0, b2);
  const __m128i c1 = _mm_unpackhi_epi32(b0, b2);
  const __m128i c2 = _mm_unpacklo_epi32(b1, b3);
  const __m128i c3 = _mm_unpackhi_epi32(b1, b3);
  out[0] = _mm_unpacklo_epi64(c0, c0);
  out[1] = _mm_unpackhi_epi64(c0, c0);
  out[2] = _mm_unpacklo_epi64(c1, c1);
  out[3] = _mm_unpackhi_epi64(c1, c1);
  out[4] = _mm_unpacklo_epi64(c2, c2);
  out[5] = _mm_unpackhi_epi64(c2, c2);
  out[6] = _mm_unpacklo_epi64(c3, c3);
  out[7] = _mm_unpackhi_epi64(c3, c3);
}
```