user: What would the C source look like for the assembly code provided here:

```asm
<mm3x3>:
  endbr64
  movsd  (%rdi),%xmm3
  movsd  0x18(%rdi),%xmm9
  movsd  (%rsi),%xmm2
  movsd  0x8(%rsi),%xmm11
  movapd %xmm3,%xmm0
  movapd %xmm9,%xmm1
  movsd  0x20(%rsi),%xmm7
  movsd  0x30(%rdi),%xmm8
  mulsd  %xmm11,%xmm1
  movsd  0x10(%rsi),%xmm10
  movapd %xmm9,%xmm4
  movsd  0x28(%rsi),%xmm6
  mulsd  %xmm2,%xmm0
  movsd  0x38(%rsi),%xmm5
  movapd %xmm2,%xmm12
  movapd %xmm11,%xmm13
  mulsd  %xmm7,%xmm4
  mulsd  %xmm5,%xmm9
  addsd  %xmm1,%xmm0
  movapd %xmm8,%xmm1
  mulsd  %xmm10,%xmm1
  addsd  %xmm1,%xmm0
  movsd  0x18(%rsi),%xmm1
  movsd  %xmm0,(%rdx)
  movapd %xmm3,%xmm0
  mulsd  %xmm1,%xmm0
  addsd  %xmm4,%xmm0
  movapd %xmm8,%xmm4
  mulsd  %xmm6,%xmm4
  addsd  %xmm4,%xmm0
  movsd  0x40(%rsi),%xmm4
  mulsd  %xmm4,%xmm8
  movsd  %xmm0,0x18(%rdx)
  movsd  0x30(%rsi),%xmm0
  mulsd  %xmm0,%xmm3
  addsd  %xmm9,%xmm3
  movsd  0x20(%rdi),%xmm9
  mulsd  %xmm9,%xmm13
  addsd  %xmm8,%xmm3
  movsd  0x38(%rdi),%xmm8
  movsd  %xmm3,0x30(%rdx)
  movsd  0x8(%rdi),%xmm3
  mulsd  %xmm3,%xmm12
  addsd  %xmm13,%xmm12
  movapd %xmm10,%xmm13
  mulsd  %xmm8,%xmm13
  addsd  %xmm13,%xmm12
  movapd %xmm7,%xmm13
  mulsd  %xmm9,%xmm13
  mulsd  %xmm5,%xmm9
  movsd  %xmm12,0x8(%rdx)
  movapd %xmm1,%xmm12
  mulsd  %xmm3,%xmm12
  mulsd  %xmm0,%xmm3
  addsd  %xmm13,%xmm12
  movapd %xmm6,%xmm13
  mulsd  %xmm8,%xmm13
  addsd  %xmm9,%xmm3
  movsd  0x10(%rdi),%xmm9
  mulsd  %xmm4,%xmm8
  mulsd  %xmm9,%xmm2
  mulsd  %xmm9,%xmm1
  mulsd  %xmm9,%xmm0
  addsd  %xmm13,%xmm12
  addsd  %xmm8,%xmm3
  movsd  0x28(%rdi),%xmm8
  mulsd  %xmm8,%xmm11
  movsd  %xmm12,0x20(%rdx)
  mulsd  %xmm8,%xmm7
  movsd  %xmm3,0x38(%rdx)
  movsd  0x40(%rdi),%xmm3
  mulsd  %xmm8,%xmm5
  mulsd  %xmm3,%xmm10
  mulsd  %xmm3,%xmm6
  mulsd  %xmm3,%xmm4
  addsd  %xmm11,%xmm2
  addsd  %xmm7,%xmm1
  addsd  %xmm5,%xmm0
  addsd  %xmm10,%xmm2
  addsd  %xmm6,%xmm1
  addsd  %xmm4,%xmm0
  movsd  %xmm2,0x10(%rdx)
  movsd  %xmm1,0x28(%rdx)
  movsd  %xmm0,0x40(%rdx)
  ret
```

assistant: ```c
void mm3x3(double *restrict a, double *restrict b, double *restrict c) {
  double *a00 __attribute__((unused)) = a++;
  double *a10 __attribute__((unused)) = a++;
  double *a20 __attribute__((unused)) = a++;
  double *a01 __attribute__((unused)) = a++;
  double *a11 __attribute__((unused)) = a++;
  double *a21 __attribute__((unused)) = a++;
  double *a02 __attribute__((unused)) = a++;
  double *a12 __attribute__((unused)) = a++;
  double *a22 __attribute__((unused)) = a++;
  ;
  double *b00 __attribute__((unused)) = b++;
  double *b10 __attribute__((unused)) = b++;
  double *b20 __attribute__((unused)) = b++;
  double *b01 __attribute__((unused)) = b++;
  double *b11 __attribute__((unused)) = b++;
  double *b21 __attribute__((unused)) = b++;
  double *b02 __attribute__((unused)) = b++;
  double *b12 __attribute__((unused)) = b++;
  double *b22 __attribute__((unused)) = b++;
  ;
  double *c00 __attribute__((unused)) = c++;
  double *c10 __attribute__((unused)) = c++;
  double *c20 __attribute__((unused)) = c++;
  double *c01 __attribute__((unused)) = c++;
  double *c11 __attribute__((unused)) = c++;
  double *c21 __attribute__((unused)) = c++;
  double *c02 __attribute__((unused)) = c++;
  double *c12 __attribute__((unused)) = c++;
  double *c22 __attribute__((unused)) = c++;
  ;
  *c00 = *a00 * *b00 + *a01 * *b10 + *a02 * *b20;
  *c01 = *a00 * *b01 + *a01 * *b11 + *a02 * *b21;
  *c02 = *a00 * *b02 + *a01 * *b12 + *a02 * *b22;
  *c10 = *a10 * *b00 + *a11 * *b10 + *a12 * *b20;
  *c11 = *a10 * *b01 + *a11 * *b11 + *a12 * *b21;
  *c12 = *a10 * *b02 + *a11 * *b12 + *a12 * *b22;
  *c20 = *a20 * *b00 + *a21 * *b10 + *a22 * *b20;
  *c21 = *a20 * *b01 + *a21 * *b11 + *a22 * *b21;
  *c22 = *a20 * *b02 + *a21 * *b12 + *a22 * *b22;
}
```