user: 请将这段汇编代码片段转换成等效的C代码：

```asm
<kernel_dttmm_uu_nt_4x4_lib4>:
  endbr64
  sub    $0x30,%rsp
  movsd  (%rsi),%xmm1
  movsd  0x8(%rdx),%xmm4
  mov    %edi,%r8d
  movsd  0x20(%rsi),%xmm7
  movsd  (%rdx),%xmm5
  pxor   %xmm0,%xmm0
  mov    %rsi,%rdi
  mulsd  %xmm1,%xmm4
  movsd  0x28(%rdx),%xmm9
  movsd  0x28(%rsi),%xmm6
  mov    %rcx,%r9
  movapd %xmm7,%xmm13
  movsd  0x38(%rdx),%xmm2
  movapd %xmm7,%xmm15
  movsd  0x20(%rdx),%xmm10
  mulsd  %xmm9,%xmm13
  movsd  0x30(%rdx),%xmm8
  movapd %xmm7,%xmm11
  movsd  0x10(%rdx),%xmm3
  mulsd  %xmm1,%xmm5
  movupd 0x60(%rdx),%xmm14
  sub    $0xffffffffffffff80,%rdi
  lea    0x80(%rdx),%rcx
  mulsd  %xmm10,%xmm15
  addsd  %xmm0,%xmm4
  mulsd  %xmm6,%xmm10
  unpcklpd %xmm14,%xmm14
  mulsd  %xmm6,%xmm9
  mulsd  %xmm8,%xmm11
  mulsd  %xmm2,%xmm7
  addsd  %xmm4,%xmm13
  movsd  0x40(%rdx),%xmm4
  addsd  %xmm0,%xmm5
  mulsd  %xmm6,%xmm8
  mulsd  %xmm2,%xmm6
  movsd  0x40(%rsi),%xmm2
  addsd  %xmm0,%xmm10
  addsd  %xmm5,%xmm15
  movsd  0x48(%rsi),%xmm5
  mulsd  %xmm1,%xmm3
  addsd  %xmm0,%xmm9
  mulsd  0x18(%rdx),%xmm1
  movapd %xmm2,%xmm12
  mulsd  %xmm4,%xmm12
  addsd  %xmm0,%xmm8
  addsd  %xmm0,%xmm6
  addsd  %xmm0,%xmm3
  addsd  %xmm0,%xmm1
  addsd  %xmm15,%xmm12
  movapd %xmm5,%xmm15
  mulsd  %xmm4,%xmm15
  addsd  %xmm3,%xmm11
  movsd  0x48(%rdx),%xmm3
  addsd  %xmm1,%xmm7
  movsd  0x50(%rsi),%xmm1
  mulsd  %xmm1,%xmm4
  addsd  %xmm10,%xmm15
  movupd 0x60(%rsi),%xmm10
  mulpd  %xmm14,%xmm10
  unpcklpd %xmm15,%xmm12
  addsd  %xmm0,%xmm4
  movq   %xmm4,%xmm4
  addpd  %xmm10,%xmm12
  movapd %xmm2,%xmm10
  mulsd  %xmm3,%xmm10
  movaps %xmm12,-0x68(%rsp)
  movupd 0x70(%rsi),%xmm12
  mulpd  %xmm12,%xmm14
  movapd %xmm5,%xmm12
  mulsd  %xmm3,%xmm12
  addsd  %xmm13,%xmm10
  mulsd  %xmm1,%xmm3
  addpd  %xmm14,%xmm4
  movupd 0x70(%rsi),%xmm14
  addsd  %xmm9,%xmm12
  movupd 0x60(%rsi),%xmm9
  addsd  %xmm0,%xmm3
  movaps %xmm4,-0x18(%rsp)
  movupd 0x60(%rdx),%xmm4
  unpcklpd %xmm12,%xmm10
  unpckhpd %xmm4,%xmm4
  movq   %xmm3,%xmm3
  mulpd  %xmm4,%xmm9
  mulpd  %xmm14,%xmm4
  addpd  %xmm9,%xmm10
  movsd  0x50(%rdx),%xmm9
  addpd  %xmm4,%xmm3
  movsd  0x50(%rdx),%xmm4
  mulsd  %xmm5,%xmm9
  mulsd  %xmm2,%xmm4
  movaps %xmm10,-0x58(%rsp)
  movaps %xmm3,-0x48(%rsp)
  movupd 0x70(%rdx),%xmm3
  unpcklpd %xmm3,%xmm3
  addsd  %xmm8,%xmm9
  movupd 0x60(%rsi),%xmm8
  addsd  %xmm11,%xmm4
  mulpd  %xmm3,%xmm8
  mulpd  %xmm14,%xmm3
  unpcklpd %xmm9,%xmm4
  addpd  %xmm8,%xmm4
  movaps %xmm4,-0x28(%rsp)
  movsd  0x50(%rdx),%xmm4
  mulsd  0x58(%rdx),%xmm2
  mulsd  0x58(%rdx),%xmm5
  mulsd  %xmm1,%xmm4
  mulsd  0x58(%rdx),%xmm1
  addsd  %xmm7,%xmm2
  addsd  %xmm6,%xmm5
  addsd  %xmm0,%xmm4
  addsd  %xmm0,%xmm1
  movapd %xmm14,%xmm0
  unpcklpd %xmm5,%xmm2
  movq   %xmm4,%xmm4
  addpd  %xmm3,%xmm4
  movupd 0x70(%rdx),%xmm3
  movq   %xmm1,%xmm1
  unpckhpd %xmm3,%xmm3
  movaps %xmm4,-0x38(%rsp)
  movupd 0x60(%rsi),%xmm4
  mulpd  %xmm3,%xmm0
  mulpd  %xmm3,%xmm4
  addpd  %xmm0,%xmm1
  addpd  %xmm4,%xmm2
  movaps %xmm1,0x8(%rsp)
  movaps %xmm2,-0x8(%rsp)
  cmp    $0x8,%r8d
  jle    L13
  sub    $0x9,%r8d
  mov    %rdi,%rdx
  mov    %rcx,%rax
  xor    %esi,%esi
  shr    $0x2,%r8d
  add    $0x1,%r8d
  nopl   (%rax)
L6:
  movupd (%rdx),%xmm7
  movupd (%rax),%xmm3
  add    $0x1,%esi
  sub    $0xffffffffffffff80,%rdx
  movupd -0x60(%rdx),%xmm1
  movlpd -0x78(%rdx),%xmm1
  sub    $0xffffffffffffff80,%rax
  movhpd -0x60(%rdx),%xmm7
  movhpd -0x60(%rax),%xmm3
  movupd -0x40(%rdx),%xmm6
  movupd -0x30(%rdx),%xmm4
  movapd %xmm7,%xmm13
  movapd %xmm1,%xmm15
  movupd -0x20(%rdx),%xmm0
  movupd -0x40(%rax),%xmm2
  mulpd  %xmm3,%xmm13
  movlpd -0x38(%rdx),%xmm0
  movhpd -0x20(%rdx),%xmm6
  movhpd -0x10(%rdx),%xmm4
  mulpd  %xmm3,%xmm15
  movupd -0x70(%rdx),%xmm5
  movupd -0x10(%rdx),%xmm9
  movhpd -0x20(%rax),%xmm2
  movlpd -0x28(%rdx),%xmm9
  movapd %xmm6,%xmm12
  movapd %xmm0,%xmm14
  movapd %xmm4,%xmm10
  mulpd  %xmm2,%xmm14
  movhpd -0x50(%rdx),%xmm5
  movupd -0x50(%rdx),%xmm8
  movlpd -0x68(%rdx),%xmm8
  mulpd  %xmm2,%xmm12
  movaps %xmm9,-0x78(%rsp)
  movapd %xmm5,%xmm11
  mulpd  %xmm2,%xmm10
  mulpd  %xmm9,%xmm2
  movapd %xmm13,%xmm9
  unpckhpd %xmm15,%xmm13
  mulpd  %xmm3,%xmm11
  unpcklpd %xmm15,%xmm9
  addpd  -0x68(%rsp),%xmm9
  mulpd  %xmm8,%xmm3
  addpd  %xmm13,%xmm9
  movapd %xmm12,%xmm13
  unpckhpd %xmm14,%xmm12
  unpcklpd %xmm14,%xmm13
  movapd %xmm0,%xmm14
  movapd %xmm11,%xmm15
  addpd  %xmm9,%xmm13
  unpcklpd %xmm3,%xmm15
  unpckhpd %xmm3,%xmm11
  movapd -0x18(%rsp),%xmm9
  movapd %xmm10,%xmm3
  unpckhpd %xmm2,%xmm10
  addpd  %xmm15,%xmm9
  unpcklpd %xmm2,%xmm3
  movapd %xmm1,%xmm15
  movupd -0x20(%rax),%xmm2
  addpd  %xmm12,%xmm13
  movlpd -0x38(%rax),%xmm2
  movapd %xmm6,%xmm12
  addpd  %xmm11,%xmm9
  mulpd  %xmm2,%xmm12
  movapd %xmm5,%xmm11
  movaps %xmm13,-0x68(%rsp)
  mulpd  %xmm2,%xmm14
  movapd %xmm7,%xmm13
  addpd  %xmm9,%xmm3
  addpd  %xmm10,%xmm3
  movapd %xmm4,%xmm10
  mulpd  %xmm2,%xmm10
  mulpd  -0x78(%rsp),%xmm2
  movaps %xmm3,-0x18(%rsp)
  movupd -0x60(%rax),%xmm3
  movlpd -0x78(%rax),%xmm3
  mulpd  %xmm3,%xmm13
  mulpd  %xmm3,%xmm15
  mulpd  %xmm3,%xmm11
  mulpd  %xmm8,%xmm3
  movapd %xmm13,%xmm9
  unpcklpd %xmm15,%xmm9
  addpd  -0x58(%rsp),%xmm9
  unpckhpd %xmm15,%xmm13
  movapd %xmm1,%xmm15
  addpd  %xmm13,%xmm9
  movapd %xmm12,%xmm13
  unpckhpd %xmm14,%xmm12
  unpcklpd %xmm14,%xmm13
  movapd %xmm11,%xmm14
  unpckhpd %xmm3,%xmm11
  unpcklpd %xmm3,%xmm14
  movapd %xmm10,%xmm3
  unpckhpd %xmm2,%xmm10
  addpd  %xmm9,%xmm13
  unpcklpd %xmm2,%xmm3
  addpd  %xmm12,%xmm13
  movapd %xmm6,%xmm12
  movaps %xmm13,-0x58(%rsp)
  movapd -0x48(%rsp),%xmm9
  movapd %xmm7,%xmm13
  movupd -0x30(%rax),%xmm2
  addpd  %xmm14,%xmm9
  movhpd -0x10(%rax),%xmm2
  movapd %xmm0,%xmm14
  mulpd  %xmm2,%xmm12
  mulpd  %xmm2,%xmm14
  addpd  %xmm11,%xmm9
  movapd %xmm5,%xmm11
  addpd  %xmm9,%xmm3
  addpd  %xmm10,%xmm3
  movapd %xmm4,%xmm10
  mulpd  %xmm2,%xmm10
  mulpd  -0x78(%rsp),%xmm2
  movaps %xmm3,-0x48(%rsp)
  movupd -0x70(%rax),%xmm3
  movhpd -0x50(%rax),%xmm3
  mulpd  %xmm3,%xmm13
  mulpd  %xmm3,%xmm15
  mulpd  %xmm3,%xmm11
  mulpd  %xmm8,%xmm3
  movapd %xmm13,%xmm9
  unpcklpd %xmm15,%xmm9
  addpd  -0x28(%rsp),%xmm9
  unpckhpd %xmm15,%xmm13
  movapd %xmm11,%xmm15
  unpcklpd %xmm3,%xmm15
  unpckhpd %xmm3,%xmm11
  movapd %xmm10,%xmm3
  addpd  %xmm13,%xmm9
  movapd %xmm12,%xmm13
  unpcklpd %xmm2,%xmm3
  unpcklpd %xmm14,%xmm13
  unpckhpd %xmm2,%xmm10
  movupd -0x10(%rax),%xmm2
  movlpd -0x28(%rax),%xmm2
  unpckhpd %xmm14,%xmm12
  addpd  %xmm9,%xmm13
  movapd -0x38(%rsp),%xmm9
  mulpd  %xmm2,%xmm6
  mulpd  %xmm2,%xmm0
  addpd  %xmm15,%xmm9
  mulpd  %xmm2,%xmm4
  mulpd  -0x78(%rsp),%xmm2
  addpd  %xmm12,%xmm13
  addpd  %xmm11,%xmm9
  movaps %xmm13,-0x28(%rsp)
  addpd  %xmm9,%xmm3
  addpd  %xmm10,%xmm3
  movaps %xmm3,-0x38(%rsp)
  movupd -0x50(%rax),%xmm3
  movlpd -0x68(%rax),%xmm3
  mulpd  %xmm3,%xmm7
  mulpd  %xmm3,%xmm1
  mulpd  %xmm3,%xmm5
  mulpd  %xmm8,%xmm3
  movapd %xmm7,%xmm8
  unpcklpd %xmm1,%xmm8
  unpckhpd %xmm1,%xmm7
  movapd %xmm6,%xmm1
  unpcklpd %xmm0,%xmm1
  unpckhpd %xmm0,%xmm6
  movapd %xmm5,%xmm0
  addpd  -0x8(%rsp),%xmm8
  unpcklpd %xmm3,%xmm0
  unpckhpd %xmm3,%xmm5
  addpd  0x8(%rsp),%xmm0
  addpd  %xmm7,%xmm8
  addpd  %xmm0,%xmm5
  movapd %xmm4,%xmm0
  unpckhpd %xmm2,%xmm4
  unpcklpd %xmm2,%xmm0
  addpd  %xmm1,%xmm8
  addpd  %xmm0,%xmm5
  addpd  %xmm6,%xmm8
  addpd  %xmm4,%xmm5
  movaps %xmm8,-0x8(%rsp)
  movaps %xmm5,0x8(%rsp)
  cmp    %r8d,%esi
  jb     L6
  shl    $0x7,%r8
  add    %r8,%rdi
  add    %r8,%rcx
L13:
  movupd (%rcx),%xmm5
  movupd 0x10(%rcx),%xmm4
  movupd 0x20(%rcx),%xmm2
  movupd 0x50(%rcx),%xmm1
  movapd %xmm5,%xmm13
  movupd 0x30(%rcx),%xmm3
  movupd (%rdi),%xmm0
  unpcklpd %xmm5,%xmm13
  unpckhpd %xmm5,%xmm5
  unpckhpd %xmm2,%xmm2
  movupd 0x40(%rdi),%xmm10
  movapd %xmm5,%xmm12
  movapd %xmm4,%xmm5
  movapd %xmm2,%xmm14
  movupd 0x50(%rdi),%xmm2
  unpcklpd %xmm4,%xmm5
  movapd %xmm1,%xmm11
  movapd %xmm3,%xmm15
  movupd 0x30(%rdi),%xmm9
  movaps %xmm5,-0x78(%rsp)
  movupd 0x20(%rdi),%xmm5
  unpcklpd %xmm1,%xmm11
  unpckhpd %xmm1,%xmm1
  movaps %xmm2,0x18(%rsp)
  unpcklpd %xmm3,%xmm15
  movapd %xmm1,%xmm2
  unpckhpd %xmm3,%xmm3
  movapd %xmm5,%xmm1
  unpckhpd %xmm4,%xmm4
  movapd %xmm0,%xmm8
  movupd 0x70(%rcx),%xmm7
  mulpd  %xmm3,%xmm1
  movupd 0x10(%rdi),%xmm6
  mulpd  %xmm4,%xmm8
  unpckhpd %xmm7,%xmm7
  addpd  -0x8(%rsp),%xmm8
  mulpd  %xmm9,%xmm3
  mulpd  %xmm6,%xmm4
  addpd  0x8(%rsp),%xmm4
  addpd  %xmm8,%xmm1
  movapd %xmm10,%xmm8
  mulpd  %xmm2,%xmm8
  addpd  %xmm4,%xmm3
  movapd 0x18(%rsp),%xmm4
  mulpd  %xmm11,%xmm10
  mulpd  %xmm4,%xmm11
  addpd  %xmm1,%xmm8
  movupd 0x60(%rdi),%xmm1
  mulpd  %xmm7,%xmm1
  addpd  %xmm1,%xmm8
  movapd %xmm2,%xmm1
  movupd 0x70(%rdi),%xmm2
  mulpd  %xmm4,%xmm1
  mulpd  %xmm7,%xmm2
  movapd -0x78(%rsp),%xmm7
  addpd  %xmm3,%xmm1
  movapd %xmm5,%xmm3
  mulpd  %xmm15,%xmm5
  mulpd  %xmm14,%xmm3
  addpd  %xmm1,%xmm2
  mulpd  %xmm9,%xmm14
  movapd %xmm0,%xmm1
  mulpd  %xmm13,%xmm1
  addpd  -0x68(%rsp),%xmm1
  mulpd  %xmm15,%xmm9
  mulpd  %xmm6,%xmm13
  addpd  -0x18(%rsp),%xmm13
  movups %xmm1,(%r9)
  movapd %xmm12,%xmm1
  mulpd  %xmm0,%xmm1
  mulpd  %xmm7,%xmm0
  addpd  -0x58(%rsp),%xmm1
  movups %xmm13,0x10(%r9)
  addpd  -0x28(%rsp),%xmm0
  mulpd  %xmm6,%xmm7
  addpd  %xmm3,%xmm1
  addpd  %xmm5,%xmm0
  movups %xmm1,0x20(%r9)
  movapd %xmm12,%xmm1
  addpd  %xmm0,%xmm10
  movapd -0x38(%rsp),%xmm0
  mulpd  %xmm6,%xmm1
  addpd  -0x48(%rsp),%xmm1
  addpd  %xmm7,%xmm0
  movups %xmm10,0x40(%r9)
  addpd  %xmm1,%xmm14
  addpd  %xmm0,%xmm9
  movups %xmm14,0x30(%r9)
  addpd  %xmm9,%xmm11
  movups %xmm11,0x50(%r9)
  movups %xmm8,0x60(%r9)
  movups %xmm2,0x70(%r9)
  add    $0x30,%rsp
  ret
```

assistant: ```c
void kernel_dttmm_uu_nt_4x4_lib4(int kmax, double *A, double *B, double *C) {
  const int bs = 4;
  int k = 0;
  double a_0, a_1, a_2, a_3, b_0, b_1, b_2, b_3, c_00 = 0, c_01 = 0, c_02 = 0, c_03 = 0, c_10 = 0, c_11 = 0, c_12 = 0, c_13 = 0, c_20 = 0, c_21 = 0, c_22 = 0, c_23 = 0, c_30 = 0, c_31 = 0, c_32 = 0, c_33 = 0;
  a_0 = A[0 + bs * 0];
  b_0 = B[0 + bs * 0];
  b_1 = B[1 + bs * 0];
  b_2 = B[2 + bs * 0];
  b_3 = B[3 + bs * 0];
  c_00 += a_0 * b_0;
  c_01 += a_0 * b_1;
  c_02 += a_0 * b_2;
  c_03 += a_0 * b_3;
  a_0 = A[0 + bs * 1];
  a_1 = A[1 + bs * 1];
  b_0 = B[0 + bs * 1];
  b_1 = B[1 + bs * 1];
  b_2 = B[2 + bs * 1];
  b_3 = B[3 + bs * 1];
  c_00 += a_0 * b_0;
  c_10 += a_1 * b_0;
  c_01 += a_0 * b_1;
  c_11 += a_1 * b_1;
  c_02 += a_0 * b_2;
  c_12 += a_1 * b_2;
  c_03 += a_0 * b_3;
  c_13 += a_1 * b_3;
  a_0 = A[0 + bs * 2];
  a_1 = A[1 + bs * 2];
  a_2 = A[2 + bs * 2];
  b_0 = B[0 + bs * 2];
  b_1 = B[1 + bs * 2];
  b_2 = B[2 + bs * 2];
  b_3 = B[3 + bs * 2];
  c_00 += a_0 * b_0;
  c_10 += a_1 * b_0;
  c_20 += a_2 * b_0;
  c_01 += a_0 * b_1;
  c_11 += a_1 * b_1;
  c_21 += a_2 * b_1;
  c_02 += a_0 * b_2;
  c_12 += a_1 * b_2;
  c_22 += a_2 * b_2;
  c_03 += a_0 * b_3;
  c_13 += a_1 * b_3;
  c_23 += a_2 * b_3;
  a_0 = A[0 + bs * 3];
  a_1 = A[1 + bs * 3];
  a_2 = A[2 + bs * 3];
  a_3 = A[3 + bs * 3];
  b_0 = B[0 + bs * 3];
  b_1 = B[1 + bs * 3];
  b_2 = B[2 + bs * 3];
  b_3 = B[3 + bs * 3];
  c_00 += a_0 * b_0;
  c_10 += a_1 * b_0;
  c_20 += a_2 * b_0;
  c_30 += a_3 * b_0;
  c_01 += a_0 * b_1;
  c_11 += a_1 * b_1;
  c_21 += a_2 * b_1;
  c_31 += a_3 * b_1;
  c_02 += a_0 * b_2;
  c_12 += a_1 * b_2;
  c_22 += a_2 * b_2;
  c_32 += a_3 * b_2;
  c_03 += a_0 * b_3;
  c_13 += a_1 * b_3;
  c_23 += a_2 * b_3;
  c_33 += a_3 * b_3;
  A += 4 * bs;
  B += 4 * bs;
  k = 4;
  for (; k < kmax - 4; k += 4) {
    a_0 = A[0 + bs * 0];
    a_1 = A[1 + bs * 0];
    a_2 = A[2 + bs * 0];
    a_3 = A[3 + bs * 0];
    b_0 = B[0 + bs * 0];
    b_1 = B[1 + bs * 0];
    b_2 = B[2 + bs * 0];
    b_3 = B[3 + bs * 0];
    c_00 += a_0 * b_0;
    c_10 += a_1 * b_0;
    c_20 += a_2 * b_0;
    c_30 += a_3 * b_0;
    c_01 += a_0 * b_1;
    c_11 += a_1 * b_1;
    c_21 += a_2 * b_1;
    c_31 += a_3 * b_1;
    c_02 += a_0 * b_2;
    c_12 += a_1 * b_2;
    c_22 += a_2 * b_2;
    c_32 += a_3 * b_2;
    c_03 += a_0 * b_3;
    c_13 += a_1 * b_3;
    c_23 += a_2 * b_3;
    c_33 += a_3 * b_3;
    a_0 = A[0 + bs * 1];
    a_1 = A[1 + bs * 1];
    a_2 = A[2 + bs * 1];
    a_3 = A[3 + bs * 1];
    b_0 = B[0 + bs * 1];
    b_1 = B[1 + bs * 1];
    b_2 = B[2 + bs * 1];
    b_3 = B[3 + bs * 1];
    c_00 += a_0 * b_0;
    c_10 += a_1 * b_0;
    c_20 += a_2 * b_0;
    c_30 += a_3 * b_0;
    c_01 += a_0 * b_1;
    c_11 += a_1 * b_1;
    c_21 += a_2 * b_1;
    c_31 += a_3 * b_1;
    c_02 += a_0 * b_2;
    c_12 += a_1 * b_2;
    c_22 += a_2 * b_2;
    c_32 += a_3 * b_2;
    c_03 += a_0 * b_3;
    c_13 += a_1 * b_3;
    c_23 += a_2 * b_3;
    c_33 += a_3 * b_3;
    a_0 = A[0 + bs * 2];
    a_1 = A[1 + bs * 2];
    a_2 = A[2 + bs * 2];
    a_3 = A[3 + bs * 2];
    b_0 = B[0 + bs * 2];
    b_1 = B[1 + bs * 2];
    b_2 = B[2 + bs * 2];
    b_3 = B[3 + bs * 2];
    c_00 += a_0 * b_0;
    c_10 += a_1 * b_0;
    c_20 += a_2 * b_0;
    c_30 += a_3 * b_0;
    c_01 += a_0 * b_1;
    c_11 += a_1 * b_1;
    c_21 += a_2 * b_1;
    c_31 += a_3 * b_1;
    c_02 += a_0 * b_2;
    c_12 += a_1 * b_2;
    c_22 += a_2 * b_2;
    c_32 += a_3 * b_2;
    c_03 += a_0 * b_3;
    c_13 += a_1 * b_3;
    c_23 += a_2 * b_3;
    c_33 += a_3 * b_3;
    a_0 = A[0 + bs * 3];
    a_1 = A[1 + bs * 3];
    a_2 = A[2 + bs * 3];
    a_3 = A[3 + bs * 3];
    b_0 = B[0 + bs * 3];
    b_1 = B[1 + bs * 3];
    b_2 = B[2 + bs * 3];
    b_3 = B[3 + bs * 3];
    c_00 += a_0 * b_0;
    c_10 += a_1 * b_0;
    c_20 += a_2 * b_0;
    c_30 += a_3 * b_0;
    c_01 += a_0 * b_1;
    c_11 += a_1 * b_1;
    c_21 += a_2 * b_1;
    c_31 += a_3 * b_1;
    c_02 += a_0 * b_2;
    c_12 += a_1 * b_2;
    c_22 += a_2 * b_2;
    c_32 += a_3 * b_2;
    c_03 += a_0 * b_3;
    c_13 += a_1 * b_3;
    c_23 += a_2 * b_3;
    c_33 += a_3 * b_3;
    A += 4 * bs;
    B += 4 * bs;
  }
  a_0 = A[0 + bs * 0];
  a_1 = A[1 + bs * 0];
  a_2 = A[2 + bs * 0];
  a_3 = A[3 + bs * 0];
  b_0 = B[0 + bs * 0];
  b_1 = B[1 + bs * 0];
  b_2 = B[2 + bs * 0];
  b_3 = B[3 + bs * 0];
  c_00 += a_0 * b_0;
  c_10 += a_1 * b_0;
  c_20 += a_2 * b_0;
  c_30 += a_3 * b_0;
  c_01 += a_0 * b_1;
  c_11 += a_1 * b_1;
  c_21 += a_2 * b_1;
  c_31 += a_3 * b_1;
  c_02 += a_0 * b_2;
  c_12 += a_1 * b_2;
  c_22 += a_2 * b_2;
  c_32 += a_3 * b_2;
  c_03 += a_0 * b_3;
  c_13 += a_1 * b_3;
  c_23 += a_2 * b_3;
  c_33 += a_3 * b_3;
  a_0 = A[0 + bs * 1];
  a_1 = A[1 + bs * 1];
  a_2 = A[2 + bs * 1];
  a_3 = A[3 + bs * 1];
  b_1 = B[1 + bs * 1];
  b_2 = B[2 + bs * 1];
  b_3 = B[3 + bs * 1];
  c_01 += a_0 * b_1;
  c_11 += a_1 * b_1;
  c_21 += a_2 * b_1;
  c_31 += a_3 * b_1;
  c_02 += a_0 * b_2;
  c_12 += a_1 * b_2;
  c_22 += a_2 * b_2;
  c_32 += a_3 * b_2;
  c_03 += a_0 * b_3;
  c_13 += a_1 * b_3;
  c_23 += a_2 * b_3;
  c_33 += a_3 * b_3;
  a_0 = A[0 + bs * 2];
  a_1 = A[1 + bs * 2];
  a_2 = A[2 + bs * 2];
  a_3 = A[3 + bs * 2];
  b_2 = B[2 + bs * 2];
  b_3 = B[3 + bs * 2];
  c_02 += a_0 * b_2;
  c_12 += a_1 * b_2;
  c_22 += a_2 * b_2;
  c_32 += a_3 * b_2;
  c_03 += a_0 * b_3;
  c_13 += a_1 * b_3;
  c_23 += a_2 * b_3;
  c_33 += a_3 * b_3;
  a_0 = A[0 + bs * 3];
  a_1 = A[1 + bs * 3];
  a_2 = A[2 + bs * 3];
  a_3 = A[3 + bs * 3];
  b_3 = B[3 + bs * 3];
  c_03 += a_0 * b_3;
  c_13 += a_1 * b_3;
  c_23 += a_2 * b_3;
  c_33 += a_3 * b_3;
  C[0 + bs * 0] = c_00;
  C[1 + bs * 0] = c_10;
  C[2 + bs * 0] = c_20;
  C[3 + bs * 0] = c_30;
  C[0 + bs * 1] = c_01;
  C[1 + bs * 1] = c_11;
  C[2 + bs * 1] = c_21;
  C[3 + bs * 1] = c_31;
  C[0 + bs * 2] = c_02;
  C[1 + bs * 2] = c_12;
  C[2 + bs * 2] = c_22;
  C[3 + bs * 2] = c_32;
  C[0 + bs * 3] = c_03;
  C[1 + bs * 3] = c_13;
  C[2 + bs * 3] = c_23;
  C[3 + bs * 3] = c_33;
}
```