user: 请将这段汇编代码片段转换成等效的C代码:

```asm
<mat_mult_3d>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %rdi,-0x8(%rbp)
  mov    %rsi,-0x10(%rbp)
  mov    %rdx,-0x18(%rbp)
  mov    -0x10(%rbp),%rax
  movsd  (%rax),%xmm1
  mov    -0x18(%rbp),%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x8,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x18,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  addsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x10,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x30,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  mov    -0x8(%rbp),%rax
  lea    0x8(%rax),%rdx
  mov    %rdx,-0x8(%rbp)
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x10(%rbp),%rax
  movsd  (%rax),%xmm1
  mov    -0x18(%rbp),%rax
  add    $0x8,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x8,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x20,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  addsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x10,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x38,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  mov    -0x8(%rbp),%rax
  lea    0x8(%rax),%rdx
  mov    %rdx,-0x8(%rbp)
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x10(%rbp),%rax
  movsd  (%rax),%xmm1
  mov    -0x18(%rbp),%rax
  add    $0x10,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x8,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x28,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  addsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x10,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x40,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  mov    -0x8(%rbp),%rax
  lea    0x8(%rax),%rdx
  mov    %rdx,-0x8(%rbp)
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x10(%rbp),%rax
  add    $0x18,%rax
  movsd  (%rax),%xmm1
  mov    -0x18(%rbp),%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x20,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x18,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  addsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x28,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x30,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  mov    -0x8(%rbp),%rax
  lea    0x8(%rax),%rdx
  mov    %rdx,-0x8(%rbp)
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x10(%rbp),%rax
  add    $0x18,%rax
  movsd  (%rax),%xmm1
  mov    -0x18(%rbp),%rax
  add    $0x8,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x20,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x20,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  addsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x28,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x38,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  mov    -0x8(%rbp),%rax
  lea    0x8(%rax),%rdx
  mov    %rdx,-0x8(%rbp)
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x10(%rbp),%rax
  add    $0x18,%rax
  movsd  (%rax),%xmm1
  mov    -0x18(%rbp),%rax
  add    $0x10,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x20,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x28,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  addsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x28,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x40,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  mov    -0x8(%rbp),%rax
  lea    0x8(%rax),%rdx
  mov    %rdx,-0x8(%rbp)
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x10(%rbp),%rax
  add    $0x30,%rax
  movsd  (%rax),%xmm1
  mov    -0x18(%rbp),%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x38,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x18,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  addsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x40,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x30,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  mov    -0x8(%rbp),%rax
  lea    0x8(%rax),%rdx
  mov    %rdx,-0x8(%rbp)
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x10(%rbp),%rax
  add    $0x30,%rax
  movsd  (%rax),%xmm1
  mov    -0x18(%rbp),%rax
  add    $0x8,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x38,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x20,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  addsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x40,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x38,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  mov    -0x8(%rbp),%rax
  lea    0x8(%rax),%rdx
  mov    %rdx,-0x8(%rbp)
  addsd  %xmm1,%xmm0
  movsd  %xmm0,(%rax)
  mov    -0x10(%rbp),%rax
  add    $0x30,%rax
  movsd  (%rax),%xmm1
  mov    -0x18(%rbp),%rax
  add    $0x10,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x38,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x28,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  addsd  %xmm0,%xmm1
  mov    -0x10(%rbp),%rax
  add    $0x40,%rax
  movsd  (%rax),%xmm2
  mov    -0x18(%rbp),%rax
  add    $0x40,%rax
  movsd  (%rax),%xmm0
  mulsd  %xmm2,%xmm0
  addsd  %xmm1,%xmm0
  mov    -0x8(%rbp),%rax
  movsd  %xmm0,(%rax)
  nop
  pop    %rbp
  ret
```

assistant: ```c
void mat_mult_3d(double *out, double *a, double *b) {
  *(out++) = a[0] * b[0] + a[1] * b[3] + a[2] * b[6];
  *(out++) = a[0] * b[1] + a[1] * b[4] + a[2] * b[7];
  *(out++) = a[0] * b[2] + a[1] * b[5] + a[2] * b[8];
  *(out++) = a[3] * b[0] + a[4] * b[3] + a[5] * b[6];
  *(out++) = a[3] * b[1] + a[4] * b[4] + a[5] * b[7];
  *(out++) = a[3] * b[2] + a[4] * b[5] + a[5] * b[8];
  *(out++) = a[6] * b[0] + a[7] * b[3] + a[8] * b[6];
  *(out++) = a[6] * b[1] + a[7] * b[4] + a[8] * b[7];
  *(out) = a[6] * b[2] + a[7] * b[5] + a[8] * b[8];
}
```