user: Demonstrate the C code that generates the assembly output below:

```asm
<dmatvec2>:
  endbr64
  push   %r15
  push   %r14
  mov    %edx,%r14d
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  mov    %rcx,%rbx
  sub    $0x30,%rsp
  mov    %edx,-0x10(%rsp)
  mov    0x68(%rsp),%rdx
  mov    %rcx,0x8(%rsp)
  mov    0x70(%rsp),%rcx
  mov    %edi,0x20(%rsp)
  mov    %esi,-0x18(%rsp)
  mov    %r8,-0x8(%rsp)
  mov    %r9,(%rsp)
  cmp    $0x7,%r14d
  jle    L9
  movslq %edi,%rax
  mov    %esi,%ebp
  mov    %r9,%r10
  lea    0x0(,%rax,8),%r15
  mov    %rax,%rdi
  mov    %r15,%rsi
  shl    $0x6,%rdi
  sub    %rax,%rsi
  mov    %rdi,-0x50(%rsp)
  mov    %rax,%rdi
  lea    (%rbx,%rsi,8),%r9
  lea    -0x8(%r14),%esi
  shl    $0x5,%rdi
  mov    %esi,%r14d
  add    %rbx,%rdi
  shr    $0x3,%r14d
  mov    %r14d,-0x30(%rsp)
  mov    %r14,-0x28(%rsp)
  shl    $0x6,%r14
  lea    0x40(%r8,%r14,1),%rsi
  movslq %ebp,%r14
  mov    %rsi,-0x48(%rsp)
  mov    %rax,%rsi
  lea    (%rax,%rax,2),%rax
  shl    $0x3,%rax
  shl    $0x4,%rsi
  mov    %rax,-0x38(%rsp)
  mov    %rsi,-0x40(%rsp)
  mov    %rbx,%rsi
  nopl   0x0(%rax,%rax,1)
L1:
  mov    -0x40(%rsp),%rax
  movsd  (%r8),%xmm6
  lea    (%r15,%rdi,1),%r11
  lea    (%r15,%rsi,1),%rbx
  movsd  (%r10),%xmm7
  movsd  0x10(%r8),%xmm2
  lea    (%r15,%r11,1),%r13
  lea    (%rsi,%rax,1),%rbp
  mov    -0x38(%rsp),%rax
  movsd  %xmm6,-0x70(%rsp)
  movsd  0x8(%r8),%xmm6
  movsd  %xmm7,-0x68(%rsp)
  movsd  0x8(%r10),%xmm7
  movsd  0x10(%r10),%xmm3
  lea    (%rsi,%rax,1),%r12
  mov    -0x18(%rsp),%eax
  movsd  %xmm6,-0x60(%rsp)
  movsd  0x18(%r8),%xmm4
  movsd  %xmm7,-0x58(%rsp)
  movsd  0x18(%r10),%xmm5
  movsd  0x20(%r8),%xmm6
  movsd  0x20(%r10),%xmm7
  movsd  0x28(%r8),%xmm8
  movsd  0x28(%r10),%xmm9
  movsd  0x30(%r8),%xmm10
  movsd  0x30(%r10),%xmm11
  movsd  0x38(%r8),%xmm12
  movsd  0x38(%r10),%xmm13
  test   %eax,%eax
  jle    L161
  xor    %eax,%eax
  nopw   0x0(%rax,%rax,1)
L68:
  movsd  (%rbx,%rax,8),%xmm1
  movsd  -0x60(%rsp),%xmm14
  movsd  (%rsi,%rax,8),%xmm0
  movsd  -0x70(%rsp),%xmm15
  mulsd  %xmm1,%xmm14
  mulsd  -0x58(%rsp),%xmm1
  mulsd  %xmm0,%xmm15
  mulsd  -0x68(%rsp),%xmm0
  addsd  (%rdx,%rax,8),%xmm15
  addsd  (%rcx,%rax,8),%xmm0
  addsd  %xmm15,%xmm14
  movapd %xmm2,%xmm15
  addsd  %xmm0,%xmm1
  movsd  0x0(%rbp,%rax,8),%xmm0
  mulsd  %xmm0,%xmm15
  mulsd  %xmm3,%xmm0
  addsd  %xmm15,%xmm14
  movapd %xmm4,%xmm15
  addsd  %xmm1,%xmm0
  movsd  (%r12,%rax,8),%xmm1
  mulsd  %xmm1,%xmm15
  mulsd  %xmm5,%xmm1
  addsd  %xmm15,%xmm14
  movapd %xmm6,%xmm15
  addsd  %xmm0,%xmm1
  movsd  (%rdi,%rax,8),%xmm0
  mulsd  %xmm0,%xmm15
  mulsd  %xmm7,%xmm0
  addsd  %xmm15,%xmm14
  movapd %xmm8,%xmm15
  addsd  %xmm1,%xmm0
  movsd  (%r11,%rax,8),%xmm1
  mulsd  %xmm1,%xmm15
  mulsd  %xmm9,%xmm1
  addsd  %xmm14,%xmm15
  movapd %xmm10,%xmm14
  addsd  %xmm1,%xmm0
  movsd  0x0(%r13,%rax,8),%xmm1
  mulsd  %xmm1,%xmm14
  mulsd  %xmm11,%xmm1
  addsd  %xmm15,%xmm14
  movapd %xmm12,%xmm15
  addsd  %xmm0,%xmm1
  movsd  (%r9,%rax,8),%xmm0
  mulsd  %xmm0,%xmm15
  mulsd  %xmm13,%xmm0
  addsd  %xmm14,%xmm15
  addsd  %xmm1,%xmm0
  movsd  %xmm15,(%rdx,%rax,8)
  movsd  %xmm0,(%rcx,%rax,8)
  add    $0x1,%rax
  cmp    %rax,%r14
  jne    L68
L161:
  mov    -0x50(%rsp),%rax
  add    $0x40,%r8
  add    $0x40,%r10
  add    %rax,%rsi
  add    %rax,%rdi
  add    %rax,%r9
  cmp    -0x48(%rsp),%r8
  jne    L1
  mov    -0x30(%rsp),%eax
  lea    0x8(,%rax,8),%eax
  mov    %eax,-0xc(%rsp)
  mov    -0x28(%rsp),%rax
  add    $0x1,%rax
  imul   -0x50(%rsp),%rax
  add    %rax,0x8(%rsp)
L2:
  mov    -0x10(%rsp),%ebp
  mov    -0xc(%rsp),%r10d
  lea    -0x3(%rbp),%eax
  cmp    %r10d,%eax
  jle    L139
  movslq 0x20(%rsp),%rax
  movslq %r10d,%r8
  mov    -0x8(%rsp),%r12
  mov    0x8(%rsp),%r13
  lea    0x0(,%r8,8),%rbx
  lea    0x0(,%rax,4),%esi
  lea    0x0(,%rax,8),%r9
  mov    %rax,%r14
  movslq %esi,%rsi
  shl    $0x4,%r14
  mov    %r9,-0x40(%rsp)
  lea    0x8(%r13),%r15
  lea    0x0(,%rsi,8),%rdi
  lea    -0x4(%rbp),%esi
  mov    -0x18(%rsp),%ebp
  add    %r14,%r9
  sub    %r10d,%esi
  mov    %rdi,-0x38(%rsp)
  mov    %r13,%rdi
  lea    (%r12,%rbx,1),%r11
  shr    $0x2,%esi
  mov    %r14,-0x60(%rsp)
  add    %r14,%rdi
  add    (%rsp),%rbx
  mov    %esi,0x24(%rsp)
  mov    %rsi,0x18(%rsp)
  lea    (%r8,%rsi,4),%rsi
  lea    0x20(%r12,%rsi,8),%rsi
  mov    %r9,-0x58(%rsp)
  mov    %rsi,-0x30(%rsp)
  mov    %ebp,%esi
  shr    %esi
  sub    $0x1,%esi
  add    $0x1,%rsi
  shl    $0x4,%rsi
  mov    %rsi,-0x20(%rsp)
  mov    %ebp,%esi
  and    $0xfffffffe,%esi
  movslq %esi,%r8
  mov    %esi,-0x14(%rsp)
  add    %r8,%rax
  lea    0x0(,%r8,8),%rsi
  lea    0xf(%rdx),%r8
  sub    %rcx,%r8
  lea    0x0(,%rax,8),%r14
  lea    (%rdx,%rsi,1),%r10
  mov    %r13,%rax
  mov    %r8,-0x28(%rsp)
  lea    -0x1(%rbp),%r8d
  lea    (%rcx,%rsi,1),%r9
  mov    %r8,0x10(%rsp)
  mov    %r14,%r8
  mov    %r15,%r14
  mov    %r8,%r15
L99:
  mov    -0x40(%rsp),%r13
  mov    -0x18(%rsp),%ebp
  movsd  (%r11),%xmm2
  movsd  (%rbx),%xmm6
  movsd  0x8(%r11),%xmm3
  movsd  0x8(%rbx),%xmm7
  lea    0x0(%r13,%rax,1),%r8
  movsd  0x10(%r11),%xmm4
  movsd  0x10(%rbx),%xmm8
  movsd  0x18(%r11),%xmm5
  movsd  0x18(%rbx),%xmm9
  test   %ebp,%ebp
  jle    L188
  mov    -0x58(%rsp),%r12
  mov    -0x60(%rsp),%rbp
  add    %r14,%r12
  add    %r14,%rbp
  mov    %r12,-0x70(%rsp)
  mov    %rbp,%r12
  sub    %r13,%r12
  cmpq   $0x1e,-0x28(%rsp)
  mov    %r12,-0x68(%rsp)
  seta   %r12b
  cmpl   $0x1,-0x18(%rsp)
  setne  %r13b
  and    %r12d,%r13d
  cmp    %r14,%rdx
  setne  %r12b
  and    %r13d,%r12d
  cmp    %r14,%rcx
  setne  %r13b
  and    %r12d,%r13d
  cmp    -0x70(%rsp),%rdx
  setne  %r12b
  and    %r13d,%r12d
  cmp    -0x70(%rsp),%rcx
  setne  %r13b
  and    %r13d,%r12d
  cmp    %rbp,%rdx
  setne  %r13b
  and    %r13d,%r12d
  cmp    %rbp,%rcx
  setne  %r13b
  and    %r12d,%r13d
  mov    -0x68(%rsp),%r12
  cmp    %r12,%rdx
  setne  %bpl
  test   %bpl,%r13b
  je     L7
  cmp    %r12,%rcx
  je     L7
  mov    -0x60(%rsp),%rbp
  mov    -0x58(%rsp),%r12
  movapd %xmm8,%xmm1
  movapd %xmm5,%xmm0
  movapd %xmm9,%xmm15
  movapd %xmm2,%xmm14
  movapd %xmm3,%xmm12
  mov    %rsi,-0x48(%rsp)
  movapd %xmm4,%xmm10
  unpcklpd %xmm1,%xmm1
  unpcklpd %xmm0,%xmm0
  add    %rax,%r12
  movapd %xmm6,%xmm13
  movapd %xmm7,%xmm11
  unpcklpd %xmm15,%xmm15
  mov    -0x20(%rsp),%rsi
  lea    0x0(%rbp,%rax,1),%r13
  movsd  %xmm2,-0x70(%rsp)
  unpcklpd %xmm14,%xmm14
  unpcklpd %xmm13,%xmm13
  movsd  %xmm3,-0x68(%rsp)
  unpcklpd %xmm12,%xmm12
  xor    %ebp,%ebp
  movapd %xmm0,%xmm3
  movsd  %xmm4,-0x50(%rsp)
  unpcklpd %xmm11,%xmm11
  unpcklpd %xmm10,%xmm10
  movapd %xmm15,%xmm2
  movapd %xmm1,%xmm4
L146:
  movupd (%rax,%rbp,1),%xmm1
  movupd (%rcx,%rbp,1),%xmm0
  movupd (%rdx,%rbp,1),%xmm15
  mulpd  %xmm13,%xmm1
  addpd  %xmm0,%xmm1
  movupd (%r8,%rbp,1),%xmm0
  mulpd  %xmm11,%xmm0
  addpd  %xmm1,%xmm0
  movupd 0x0(%r13,%rbp,1),%xmm1
  mulpd  %xmm4,%xmm1
  addpd  %xmm0,%xmm1
  movupd (%r12,%rbp,1),%xmm0
  mulpd  %xmm2,%xmm0
  addpd  %xmm0,%xmm1
  movupd (%rax,%rbp,1),%xmm0
  mulpd  %xmm14,%xmm0
  addpd  %xmm15,%xmm0
  movupd (%r8,%rbp,1),%xmm15
  mulpd  %xmm12,%xmm15
  addpd  %xmm0,%xmm15
  movupd 0x0(%r13,%rbp,1),%xmm0
  mulpd  %xmm10,%xmm0
  addpd  %xmm15,%xmm0
  movupd (%r12,%rbp,1),%xmm15
  mulpd  %xmm3,%xmm15
  addpd  %xmm15,%xmm0
  movups %xmm0,(%rdx,%rbp,1)
  movups %xmm1,(%rcx,%rbp,1)
  add    $0x10,%rbp
  cmp    %rsi,%rbp
  jne    L146
  movsd  -0x70(%rsp),%xmm2
  movsd  -0x68(%rsp),%xmm3
  movsd  -0x50(%rsp),%xmm4
  mov    -0x48(%rsp),%rsi
  mov    -0x18(%rsp),%r13d
  cmp    %r13d,-0x14(%rsp)
  je     L188
  movsd  (%rax,%rsi,1),%xmm0
  movsd  (%r9),%xmm1
  mulsd  %xmm0,%xmm2
  mulsd  %xmm6,%xmm0
  addsd  (%r10),%xmm2
  addsd  %xmm0,%xmm1
  movsd  (%r8,%rsi,1),%xmm0
  mulsd  %xmm0,%xmm3
  mulsd  %xmm7,%xmm0
  addsd  %xmm2,%xmm3
  addsd  %xmm0,%xmm1
  movsd  (%rdi,%rsi,1),%xmm0
  mulsd  %xmm0,%xmm4
  mulsd  %xmm8,%xmm0
  addsd  %xmm3,%xmm4
  addsd  %xmm0,%xmm1
  movsd  (%rdi,%r15,1),%xmm0
  mulsd  %xmm0,%xmm5
  mulsd  %xmm9,%xmm0
  addsd  %xmm4,%xmm5
  addsd  %xmm1,%xmm0
  movsd  %xmm5,(%r10)
  movsd  %xmm0,(%r9)
L188:
  mov    -0x38(%rsp),%r8
  add    $0x20,%r11
  add    $0x20,%rbx
  add    %r8,%rax
  add    %r8,%rdi
  add    %r8,%r14
  cmp    -0x30(%rsp),%r11
  jne    L99
  mov    -0xc(%rsp),%eax
  mov    0x24(%rsp),%edi
  lea    0x4(%rax,%rdi,4),%eax
  mov    %eax,-0xc(%rsp)
  mov    0x18(%rsp),%rax
  add    $0x1,%rax
  imul   %r8,%rax
  add    %rax,0x8(%rsp)
L139:
  mov    -0xc(%rsp),%eax
  cmp    %eax,-0x10(%rsp)
  jle    L176
  movslq 0x20(%rsp),%rbp
  mov    -0x18(%rsp),%ebx
  shl    $0x3,%rbp
  test   %ebx,%ebx
  jle    L176
  movslq %eax,%r10
  mov    %ebx,%r13d
  mov    %ebx,%eax
  mov    0x8(%rsp),%r11
  and    $0xfffffffe,%r13d
  shr    %eax
  movslq %ebx,%r12
  lea    -0x1(%rax),%r9d
  mov    %r13d,%r8d
  lea    0xf(%rdx),%rax
  mov    %r13d,-0x70(%rsp)
  shl    $0x3,%r8
  add    $0x1,%r9
  sub    %rcx,%rax
  add    $0x8,%r11
  shl    $0x4,%r9
  lea    (%rdx,%r8,1),%rdi
  lea    (%rcx,%r8,1),%rsi
  mov    %rax,%r15
  mov    %ebx,%r13d
L216:
  mov    -0x8(%rsp),%rbx
  cmp    $0x1e,%r15
  lea    -0x8(%r11),%rax
  seta   %r14b
  cmp    $0x1,%r13d
  movsd  (%rbx,%r10,8),%xmm1
  mov    (%rsp),%rbx
  movsd  (%rbx,%r10,8),%xmm3
  setne  %bl
  and    %r14d,%ebx
  cmp    %r11,%rdx
  setne  %r14b
  test   %r14b,%bl
  je     L14
  cmp    %r11,%rcx
  je     L14
  movapd %xmm1,%xmm5
  movapd %xmm3,%xmm4
  xor    %ebx,%ebx
  unpcklpd %xmm5,%xmm5
  unpcklpd %xmm4,%xmm4
  nopl   0x0(%rax,%rax,1)
L77:
  movupd (%rax,%rbx,1),%xmm2
  movupd (%rax,%rbx,1),%xmm0
  movupd (%rcx,%rbx,1),%xmm6
  movupd (%rdx,%rbx,1),%xmm7
  mulpd  %xmm4,%xmm2
  mulpd  %xmm5,%xmm0
  addpd  %xmm6,%xmm2
  addpd  %xmm7,%xmm0
  movups %xmm0,(%rdx,%rbx,1)
  movups %xmm2,(%rcx,%rbx,1)
  add    $0x10,%rbx
  cmp    %rbx,%r9
  jne    L77
  cmp    %r13d,-0x70(%rsp)
  je     L100
  movsd  (%rax,%r8,1),%xmm0
  movsd  (%rsi),%xmm2
  mulsd  %xmm0,%xmm1
  mulsd  %xmm3,%xmm0
  addsd  (%rdi),%xmm1
  movsd  %xmm1,(%rdi)
  addsd  %xmm2,%xmm0
  movsd  %xmm0,(%rsi)
L100:
  add    $0x1,%r10
  add    %rbp,%r11
  cmp    %r10d,-0x10(%rsp)
  jg     L216
L176:
  add    $0x30,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nop
L7:
  mov    -0x40(%rsp),%rbp
  mov    %rsi,-0x70(%rsp)
  mov    0x10(%rsp),%rsi
  lea    0x0(%rbp,%rdi,1),%r13
  xor    %ebp,%ebp
  cs nopw 0x0(%rax,%rax,1)
L96:
  movsd  (%rax,%rbp,8),%xmm0
  movapd %xmm2,%xmm11
  movsd  (%rcx,%rbp,8),%xmm1
  mov    %rbp,%r12
  movapd %xmm3,%xmm10
  mulsd  %xmm0,%xmm11
  mulsd  %xmm6,%xmm0
  addsd  (%rdx,%rbp,8),%xmm11
  addsd  %xmm0,%xmm1
  movsd  (%r8,%rbp,8),%xmm0
  mulsd  %xmm0,%xmm10
  mulsd  %xmm7,%xmm0
  addsd  %xmm11,%xmm10
  movapd %xmm4,%xmm11
  addsd  %xmm0,%xmm1
  movsd  (%rdi,%rbp,8),%xmm0
  mulsd  %xmm0,%xmm11
  mulsd  %xmm8,%xmm0
  addsd  %xmm10,%xmm11
  movapd %xmm5,%xmm10
  addsd  %xmm0,%xmm1
  movsd  0x0(%r13,%rbp,8),%xmm0
  mulsd  %xmm0,%xmm10
  mulsd  %xmm9,%xmm0
  addsd  %xmm11,%xmm10
  addsd  %xmm1,%xmm0
  movsd  %xmm10,(%rdx,%rbp,8)
  movsd  %xmm0,(%rcx,%rbp,8)
  add    $0x1,%rbp
  cmp    %r12,%rsi
  jne    L96
  mov    -0x70(%rsp),%rsi
  jmp    L188
L14:
  xor    %ebx,%ebx
  nopw   0x0(%rax,%rax,1)
L52:
  movsd  (%rax,%rbx,8),%xmm0
  movapd %xmm1,%xmm2
  movsd  (%rcx,%rbx,8),%xmm4
  mulsd  %xmm0,%xmm2
  mulsd  %xmm3,%xmm0
  addsd  (%rdx,%rbx,8),%xmm2
  movsd  %xmm2,(%rdx,%rbx,8)
  addsd  %xmm4,%xmm0
  movsd  %xmm0,(%rcx,%rbx,8)
  add    $0x1,%rbx
  cmp    %rbx,%r12
  jne    L52
  jmp    L100
L9:
  movl   $0x0,-0xc(%rsp)
  jmp    L2
```

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;
  }
}
```