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

```asm
<dmatvec2>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %rbx
  sub    $0x40,%rsp
  mov    %edi,-0x5c(%rbp)
  mov    %esi,-0x60(%rbp)
  mov    %edx,-0x64(%rbp)
  mov    %rcx,-0x70(%rbp)
  mov    %r8,-0x78(%rbp)
  mov    %r9,-0x80(%rbp)
  mov    $0x0,%ebx
  mov    -0x70(%rbp),%rax
  mov    %rax,-0x50(%rbp)
  jmp    L7
L30:
  mov    -0x50(%rbp),%rax
  mov    %rax,-0x48(%rbp)
  mov    -0x5c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x40(%rbp)
  mov    -0x5c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x38(%rbp)
  mov    -0x5c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x30(%rbp)
  mov    -0x5c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x28(%rbp)
  mov    -0x5c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x20(%rbp)
  mov    -0x5c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x18(%rbp)
  mov    -0x5c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x10(%rbp)
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  movapd %xmm3,%xmm8
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x80(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm4
  movapd %xmm4,%xmm9
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm5
  movapd %xmm5,%xmm10
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x80(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm6
  movapd %xmm6,%xmm11
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  movapd %xmm3,%xmm12
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x80(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm4
  movapd %xmm4,%xmm13
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm5
  movapd %xmm5,%xmm14
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x80(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm6
  movapd %xmm6,%xmm15
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm7
  movsd  %xmm7,-0x88(%rbp)
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x80(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  movsd  %xmm3,-0x90(%rbp)
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm4
  movsd  %xmm4,-0x98(%rbp)
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x80(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm5
  movsd  %xmm5,-0xa0(%rbp)
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm6
  movsd  %xmm6,-0xa8(%rbp)
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x80(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm7
  movsd  %xmm7,-0xb0(%rbp)
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  movsd  %xmm3,-0xb8(%rbp)
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x80(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm4
  movsd  %xmm4,-0xc0(%rbp)
  movl   $0x0,-0x54(%rbp)
  jmp    L52
L95:
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm5
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x18(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm6
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  movapd %xmm8,%xmm0
  mulsd  %xmm1,%xmm0
  movapd %xmm0,%xmm7
  addsd  %xmm5,%xmm7
  movapd %xmm9,%xmm2
  mulsd  %xmm2,%xmm1
  movapd %xmm1,%xmm0
  movapd %xmm0,%xmm1
  addsd  %xmm6,%xmm1
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm2
  movapd %xmm10,%xmm0
  mulsd  %xmm2,%xmm0
  addsd  %xmm7,%xmm0
  movapd %xmm0,%xmm7
  movapd %xmm11,%xmm3
  mulsd  %xmm3,%xmm2
  movapd %xmm2,%xmm0
  movapd %xmm0,%xmm2
  addsd  %xmm1,%xmm2
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  movapd %xmm12,%xmm0
  mulsd  %xmm3,%xmm0
  addsd  %xmm7,%xmm0
  movapd %xmm0,%xmm7
  movapd %xmm13,%xmm1
  mulsd  %xmm1,%xmm3
  movapd %xmm3,%xmm0
  movapd %xmm0,%xmm3
  addsd  %xmm2,%xmm3
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm4
  movapd %xmm14,%xmm0
  mulsd  %xmm4,%xmm0
  movapd %xmm0,%xmm6
  addsd  %xmm7,%xmm6
  movapd %xmm15,%xmm7
  mulsd  %xmm7,%xmm4
  movapd %xmm4,%xmm0
  movapd %xmm0,%xmm4
  addsd  %xmm3,%xmm4
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm5
  movsd  -0x88(%rbp),%xmm0
  mulsd  %xmm5,%xmm0
  movapd %xmm0,%xmm7
  addsd  %xmm6,%xmm7
  mulsd  -0x90(%rbp),%xmm5
  movapd %xmm5,%xmm0
  movapd %xmm0,%xmm5
  addsd  %xmm4,%xmm5
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm6
  movsd  -0x98(%rbp),%xmm0
  mulsd  %xmm6,%xmm0
  movapd %xmm0,%xmm1
  addsd  %xmm7,%xmm1
  mulsd  -0xa0(%rbp),%xmm6
  movapd %xmm6,%xmm0
  movapd %xmm0,%xmm2
  addsd  %xmm5,%xmm2
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm7
  movsd  -0xa8(%rbp),%xmm0
  mulsd  %xmm7,%xmm0
  movapd %xmm0,%xmm3
  addsd  %xmm1,%xmm3
  mulsd  -0xb0(%rbp),%xmm7
  movapd %xmm7,%xmm0
  movapd %xmm0,%xmm4
  addsd  %xmm2,%xmm4
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x10(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  movsd  -0xb8(%rbp),%xmm0
  mulsd  %xmm1,%xmm0
  movapd %xmm0,%xmm5
  addsd  %xmm3,%xmm5
  mulsd  -0xc0(%rbp),%xmm1
  movapd %xmm1,%xmm0
  movapd %xmm0,%xmm6
  addsd  %xmm4,%xmm6
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  movsd  %xmm5,(%rax)
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x18(%rbp),%rax
  add    %rdx,%rax
  movsd  %xmm6,(%rax)
  addl   $0x1,-0x54(%rbp)
L52:
  mov    -0x54(%rbp),%eax
  cmp    -0x60(%rbp),%eax
  jl     L95
  mov    -0x5c(%rbp),%eax
  shl    $0x3,%eax
  cltq
  shl    $0x3,%rax
  add    %rax,-0x50(%rbp)
L7:
  mov    -0x64(%rbp),%eax
  sub    $0x7,%eax
  cmp    %eax,%ebx
  jl     L30
  jmp    L70
L8:
  mov    -0x50(%rbp),%rax
  mov    %rax,-0x48(%rbp)
  mov    -0x5c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x40(%rbp)
  mov    -0x5c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x38(%rbp)
  mov    -0x5c(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x30(%rbp)
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm7
  movapd %xmm7,%xmm8
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x80(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  movapd %xmm3,%xmm9
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm1
  movapd %xmm1,%xmm10
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x80(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm2
  movapd %xmm2,%xmm11
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm7
  movapd %xmm7,%xmm12
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x80(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  movapd %xmm3,%xmm13
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm4
  movapd %xmm4,%xmm14
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x80(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm5
  movapd %xmm5,%xmm15
  movl   $0x0,-0x54(%rbp)
  jmp    L100
L64:
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm6
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x18(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm2
  movapd %xmm8,%xmm0
  mulsd  %xmm2,%xmm0
  movapd %xmm0,%xmm7
  addsd  %xmm6,%xmm7
  movapd %xmm9,%xmm1
  mulsd  %xmm1,%xmm2
  movapd %xmm2,%xmm0
  movapd %xmm0,%xmm1
  addsd  %xmm3,%xmm1
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm3
  movapd %xmm10,%xmm0
  mulsd  %xmm3,%xmm0
  movapd %xmm0,%xmm2
  addsd  %xmm7,%xmm2
  movapd %xmm11,%xmm7
  mulsd  %xmm7,%xmm3
  movapd %xmm3,%xmm0
  movapd %xmm0,%xmm3
  addsd  %xmm1,%xmm3
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm4
  movapd %xmm12,%xmm0
  mulsd  %xmm4,%xmm0
  movapd %xmm0,%xmm6
  addsd  %xmm2,%xmm6
  movapd %xmm13,%xmm2
  mulsd  %xmm2,%xmm4
  movapd %xmm4,%xmm0
  movapd %xmm0,%xmm4
  addsd  %xmm3,%xmm4
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x30(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm5
  movapd %xmm14,%xmm0
  mulsd  %xmm5,%xmm0
  movapd %xmm0,%xmm7
  addsd  %xmm6,%xmm7
  movapd %xmm15,%xmm1
  mulsd  %xmm1,%xmm5
  movapd %xmm5,%xmm0
  movapd %xmm0,%xmm5
  addsd  %xmm4,%xmm5
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  movsd  %xmm7,(%rax)
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x18(%rbp),%rax
  add    %rdx,%rax
  movsd  %xmm5,(%rax)
  addl   $0x1,-0x54(%rbp)
L100:
  mov    -0x54(%rbp),%eax
  cmp    -0x60(%rbp),%eax
  jl     L64
  mov    -0x5c(%rbp),%eax
  shl    $0x2,%eax
  cltq
  shl    $0x3,%rax
  add    %rax,-0x50(%rbp)
L70:
  mov    -0x64(%rbp),%eax
  sub    $0x3,%eax
  cmp    %eax,%ebx
  jl     L8
  jmp    L35
L44:
  mov    -0x50(%rbp),%rax
  mov    %rax,-0x48(%rbp)
  movslq %ebx,%rax
  lea    0x0(,%rax,8),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm4
  movapd %xmm4,%xmm8
  mov    %ebx,%eax
  lea    0x1(%rax),%ebx
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x80(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm5
  movapd %xmm5,%xmm9
  movl   $0x0,-0x54(%rbp)
  jmp    L79
L58:
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm2
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x18(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm7
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm6
  movapd %xmm8,%xmm0
  mulsd  %xmm6,%xmm0
  movapd %xmm0,%xmm1
  addsd  %xmm2,%xmm1
  movapd %xmm9,%xmm4
  mulsd  %xmm4,%xmm6
  movapd %xmm6,%xmm0
  movapd %xmm0,%xmm2
  addsd  %xmm7,%xmm2
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x10(%rbp),%rax
  add    %rdx,%rax
  movsd  %xmm1,(%rax)
  mov    -0x54(%rbp),%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x18(%rbp),%rax
  add    %rdx,%rax
  movsd  %xmm2,(%rax)
  addl   $0x1,-0x54(%rbp)
L79:
  mov    -0x54(%rbp),%eax
  cmp    -0x60(%rbp),%eax
  jl     L58
  mov    -0x5c(%rbp),%eax
  cltq
  shl    $0x3,%rax
  add    %rax,-0x50(%rbp)
L35:
  cmp    -0x64(%rbp),%ebx
  jl     L44
  nop
  nop
  mov    -0x8(%rbp),%rbx
  leave
  ret
```

assistant: ```c
void dmatvec2(int lda, int m, int n, double *A, double *x0, double *x1, double *y0, double *y1) {
  register double v00, v10, v20, v30, v40, v50, v60, v70, v01, v11, v21, v31, v41, v51, v61, v71;
  register double t0, t1, t2, t3, t4, t5, t6, t7;
  register double f0, f1;
  double *Mki0, *Mki1, *Mki2, *Mki3, *Mki4, *Mki5, *Mki6, *Mki7;
  register int firstcol = 0;
  double *M0;
  int k;
  M0 = &A[0];
  while (firstcol < n - 7) {
    Mki0 = M0;
    Mki1 = Mki0 + lda;
    Mki2 = Mki1 + lda;
    Mki3 = Mki2 + lda;
    Mki4 = Mki3 + lda;
    Mki5 = Mki4 + lda;
    Mki6 = Mki5 + lda;
    Mki7 = Mki6 + lda;
    v00 = x0[firstcol];
    v01 = x1[firstcol++];
    v10 = x0[firstcol];
    v11 = x1[firstcol++];
    v20 = x0[firstcol];
    v21 = x1[firstcol++];
    v30 = x0[firstcol];
    v31 = x1[firstcol++];
    v40 = x0[firstcol];
    v41 = x1[firstcol++];
    v50 = x0[firstcol];
    v51 = x1[firstcol++];
    v60 = x0[firstcol];
    v61 = x1[firstcol++];
    v70 = x0[firstcol];
    v71 = x1[firstcol++];
    for (k = 0; k < m; k++) {
      f0 = y0[k];
      f1 = y1[k];
      t0 = Mki0[k];
      f0 += v00 * t0;
      f1 += v01 * t0;
      t1 = Mki1[k];
      f0 += v10 * t1;
      f1 += v11 * t1;
      t2 = Mki2[k];
      f0 += v20 * t2;
      f1 += v21 * t2;
      t3 = Mki3[k];
      f0 += v30 * t3;
      f1 += v31 * t3;
      t4 = Mki4[k];
      f0 += v40 * t4;
      f1 += v41 * t4;
      t5 = Mki5[k];
      f0 += v50 * t5;
      f1 += v51 * t5;
      t6 = Mki6[k];
      f0 += v60 * t6;
      f1 += v61 * t6;
      t7 = Mki7[k];
      f0 += v70 * t7;
      f1 += v71 * t7;
      y0[k] = f0;
      y1[k] = f1;
    }
    M0 += 8 * lda;
  }
  while (firstcol < n - 3) {
    Mki0 = M0;
    Mki1 = Mki0 + lda;
    Mki2 = Mki1 + lda;
    Mki3 = Mki2 + lda;
    v00 = x0[firstcol];
    v01 = x1[firstcol++];
    v10 = x0[firstcol];
    v11 = x1[firstcol++];
    v20 = x0[firstcol];
    v21 = x1[firstcol++];
    v30 = x0[firstcol];
    v31 = x1[firstcol++];
    for (k = 0; k < m; k++) {
      f0 = y0[k];
      f1 = y1[k];
      t0 = Mki0[k];
      f0 += v00 * t0;
      f1 += v01 * t0;
      t1 = Mki1[k];
      f0 += v10 * t1;
      f1 += v11 * t1;
      t2 = Mki2[k];
      f0 += v20 * t2;
      f1 += v21 * t2;
      t3 = Mki3[k];
      f0 += v30 * t3;
      f1 += v31 * t3;
      y0[k] = f0;
      y1[k] = f1;
    }
    M0 += 4 * lda;
  }
  while (firstcol < n) {
    Mki0 = M0;
    v00 = x0[firstcol];
    v01 = x1[firstcol++];
    for (k = 0; k < m; k++) {
      f0 = y0[k];
      f1 = y1[k];
      t0 = Mki0[k];
      f0 += v00 * t0;
      f1 += v01 * t0;
      y0[k] = f0;
      y1[k] = f1;
    }
    M0 += lda;
  }
}
```