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

```asm
<merge_matrix>:
  endbr64
  push   %r15
  mov    %edi,%r10d
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  mov    %rdx,%rbp
  push   %rbx
  mov    0x40(%rsp),%rdx
  mov    %edi,-0x68(%rsp)
  mov    %esi,-0x48(%rsp)
  mov    %r8,-0x10(%rsp)
  mov    %r9,-0x30(%rsp)
  test   %edi,%edi
  jle    L162
  movslq 0x38(%rsp),%rax
  mov    0x38(%rsp),%r15d
  mov    %edi,%esi
  mov    %rcx,%rbx
  movapd %xmm0,%xmm5
  movapd %xmm1,%xmm6
  movapd %xmm0,%xmm4
  mov    %rbp,%r8
  shl    $0x3,%rax
  sub    %esi,%r15d
  xor    %r11d,%r11d
  xor    %r9d,%r9d
  mov    %rax,-0x50(%rsp)
  movslq %edi,%rax
  mov    %r15d,%r13d
  unpcklpd %xmm5,%xmm5
  mov    %rax,-0x20(%rsp)
  shl    $0x3,%rax
  and    $0xfffffffe,%r13d
  unpcklpd %xmm6,%xmm6
  mov    %rax,-0x58(%rsp)
  lea    (%rdx,%rax,1),%r10
  mov    %edi,%eax
  and    $0xfffffffe,%edi
  shr    %eax
  mov    %r15d,-0x3c(%rsp)
  lea    -0x1(%rax),%r12d
  mov    %r15d,%eax
  movl   $0x0,-0x64(%rsp)
  shr    %eax
  add    $0x1,%r12
  sub    $0x1,%eax
  shl    $0x4,%r12
  add    $0x1,%rax
  shl    $0x4,%rax
  mov    %rax,-0x38(%rsp)
  mov    %esi,%eax
  xor    %esi,%esi
  lea    -0x1(%rax),%ecx
  mov    %rax,-0x28(%rsp)
  lea    0x0(%r13,%rax,1),%r14d
  lea    -0x1(%r15),%eax
  mov    %ecx,-0x44(%rsp)
  mov    %rdx,%rcx
  mov    %eax,-0x40(%rsp)
  nopl   0x0(%rax)
L9:
  cmpl   $0x1,-0x44(%rsp)
  jbe    L225
  lea    0x8(%r8),%r15
  xor    %eax,%eax
  cmp    %r15,%rcx
  je     L225
  nopw   0x0(%rax,%rax,1)
L109:
  movupd (%r8,%rax,1),%xmm0
  mulpd  %xmm5,%xmm0
  movups %xmm0,(%rcx,%rax,1)
  add    $0x10,%rax
  cmp    %r12,%rax
  jne    L109
  cmp    -0x68(%rsp),%edi
  je     L72
  lea    (%r11,%rdi,1),%r15d
  lea    (%rsi,%rdi,1),%eax
  movslq %r15d,%r15
  cltq
  movsd  0x0(%rbp,%r15,8),%xmm0
  mulsd  %xmm4,%xmm0
  movsd  %xmm0,(%rdx,%rax,8)
L72:
  mov    -0x68(%rsp),%eax
  cmp    0x38(%rsp),%eax
  jge    L64
  movslq %r9d,%rax
  cmpl   $0x1,-0x40(%rsp)
  lea    0x8(,%rax,8),%rax
  jbe    L258
  lea    (%rbx,%rax,1),%r15
  cmp    %r15,%r10
  je     L258
  mov    %rdx,-0x60(%rsp)
  mov    -0x38(%rsp),%rdx
  lea    -0x8(%rbx,%rax,1),%r15
  xor    %eax,%eax
  nopw   0x0(%rax,%rax,1)
L135:
  movupd (%r15,%rax,1),%xmm0
  mulpd  %xmm6,%xmm0
  movups %xmm0,(%r10,%rax,1)
  add    $0x10,%rax
  cmp    %rdx,%rax
  jne    L135
  mov    -0x60(%rsp),%rdx
  cmp    %r13d,-0x3c(%rsp)
  je     L64
  lea    (%r9,%r13,1),%r15d
  lea    (%rsi,%r14,1),%eax
  movslq %r15d,%r15
  cltq
  movsd  (%rbx,%r15,8),%xmm0
  mulsd  %xmm1,%xmm0
  movsd  %xmm0,(%rdx,%rax,8)
L64:
  mov    -0x50(%rsp),%r15
  addl   $0x1,-0x64(%rsp)
  mov    -0x64(%rsp),%eax
  add    -0x58(%rsp),%r8
  add    %r15,%rcx
  add    %r15,%r10
  mov    -0x68(%rsp),%r15d
  add    -0x48(%rsp),%r9d
  add    0x38(%rsp),%esi
  add    %r15d,%r11d
  cmp    %eax,%r15d
  jne    L9
  mov    %r15d,%r10d
L162:
  cmp    0x38(%rsp),%r10d
  jge    L8
  mov    0x38(%rsp),%eax
  movslq -0x48(%rsp),%rdi
  movslq %r10d,%r11
  mov    %r10d,%r15d
  mov    0x38(%rsp),%r14d
  movslq 0x38(%rsp),%rcx
  movapd %xmm2,%xmm4
  movapd %xmm3,%xmm1
  imul   %r10d,%eax
  shl    $0x3,%rdi
  mov    -0x30(%rsp),%r8
  mov    %r11,-0x28(%rsp)
  sub    %r10d,%r14d
  mov    %rdi,-0x58(%rsp)
  shl    $0x3,%rcx
  unpcklpd %xmm4,%xmm4
  mov    %r14d,%edi
  mov    %rcx,-0x50(%rsp)
  mov    %r14d,%ebp
  unpcklpd %xmm1,%xmm1
  shr    %edi
  movslq %eax,%rsi
  mov    %r14d,-0x40(%rsp)
  and    $0xfffffffe,%ebp
  lea    -0x1(%rdi),%ebx
  mov    %r11,%rdi
  lea    (%rdx,%rsi,8),%rcx
  add    %r11,%rsi
  neg    %rdi
  lea    (%rdx,%rsi,8),%r9
  mov    %r10d,%esi
  add    $0x1,%rbx
  shl    $0x3,%rdi
  shr    %esi
  mov    %r15d,-0x64(%rsp)
  lea    (%r10,%rbp,1),%r13d
  mov    %rdi,-0x20(%rsp)
  mov    %r10d,%edi
  lea    -0x1(%rsi),%r12d
  mov    %r10d,%esi
  sub    $0x1,%edi
  add    $0x1,%r12
  and    $0xfffffffe,%esi
  shl    $0x4,%rbx
  mov    %edi,-0x3c(%rsp)
  shl    $0x4,%r12
  xor    %r10d,%r10d
  xor    %r11d,%r11d
  mov    %rdi,-0x18(%rsp)
  lea    -0x1(%r14),%edi
  mov    %r8,%r15
  mov    %edi,-0x44(%rsp)
  mov    %r12,-0x38(%rsp)
  mov    -0x10(%rsp),%r12
  nop
L167:
  mov    -0x68(%rsp),%edi
  test   %edi,%edi
  jle    L248
  movslq %r10d,%rdi
  lea    0x8(,%rdi,8),%rdi
  lea    (%r12,%rdi,1),%r14
  cmp    %r14,%rcx
  lea    -0x8(%r12,%rdi,1),%r14
  mov    $0x0,%edi
  je     L155
  cmpl   $0x1,-0x3c(%rsp)
  jbe    L155
  mov    %eax,-0x60(%rsp)
  mov    -0x38(%rsp),%rax
  xchg   %ax,%ax
L13:
  movupd (%r14,%rdi,1),%xmm0
  mulpd  %xmm4,%xmm0
  movups %xmm0,(%rcx,%rdi,1)
  add    $0x10,%rdi
  cmp    %rdi,%rax
  jne    L13
  mov    -0x60(%rsp),%eax
  cmp    %esi,-0x68(%rsp)
  je     L248
  lea    (%r10,%rsi,1),%r14d
  lea    (%rsi,%rax,1),%edi
  movslq %r14d,%r14
  movslq %edi,%rdi
  movsd  (%r12,%r14,8),%xmm0
  mulsd  %xmm2,%xmm0
  movsd  %xmm0,(%rdx,%rdi,8)
L248:
  lea    0x8(%r8),%rdi
  cmp    %rdi,%r9
  je     L12
  cmpl   $0x1,-0x44(%rsp)
  jbe    L12
  xor    %edi,%edi
  nopl   0x0(%rax,%rax,1)
L47:
  movupd (%r8,%rdi,1),%xmm0
  mulpd  %xmm1,%xmm0
  movups %xmm0,(%r9,%rdi,1)
  add    $0x10,%rdi
  cmp    %rbx,%rdi
  jne    L47
  cmp    -0x40(%rsp),%ebp
  je     L297
  lea    (%r11,%rbp,1),%r14d
  lea    0x0(%r13,%rax,1),%edi
  movslq %r14d,%r14
  movslq %edi,%rdi
  movsd  (%r15,%r14,8),%xmm0
  mulsd  %xmm3,%xmm0
  movsd  %xmm0,(%rdx,%rdi,8)
L297:
  mov    -0x50(%rsp),%r14
  addl   $0x1,-0x64(%rsp)
  add    -0x48(%rsp),%r11d
  mov    -0x64(%rsp),%edi
  add    0x38(%rsp),%eax
  add    %r14,%rcx
  add    -0x58(%rsp),%r8
  add    %r14,%r9
  add    -0x68(%rsp),%r10d
  cmp    %edi,0x38(%rsp)
  jne    L167
L8:
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L12:
  mov    -0x20(%rsp),%rdi
  mov    %eax,-0x60(%rsp)
  mov    0x38(%rsp),%eax
  lea    (%r8,%rdi,1),%r14
  mov    -0x28(%rsp),%rdi
  cs nopw 0x0(%rax,%rax,1)
L53:
  movsd  (%r14,%rdi,8),%xmm0
  mulsd  %xmm3,%xmm0
  movsd  %xmm0,(%rcx,%rdi,8)
  add    $0x1,%rdi
  cmp    %edi,%eax
  jg     L53
  mov    -0x60(%rsp),%eax
  jmp    L297
L225:
  mov    -0x28(%rsp),%r15
  xor    %eax,%eax
  nopw   0x0(%rax,%rax,1)
L186:
  movsd  (%r8,%rax,8),%xmm0
  mulsd  %xmm4,%xmm0
  movsd  %xmm0,(%rcx,%rax,8)
  add    $0x1,%rax
  cmp    %rax,%r15
  jne    L186
  jmp    L72
  nopl   (%rax)
L155:
  mov    %r11d,-0x60(%rsp)
  mov    %eax,-0x30(%rsp)
  mov    -0x18(%rsp),%rax
  xchg   %ax,%ax
L295:
  movsd  (%r14,%rdi,8),%xmm0
  mov    %rdi,%r11
  mulsd  %xmm2,%xmm0
  movsd  %xmm0,(%rcx,%rdi,8)
  add    $0x1,%rdi
  cmp    %r11,%rax
  jne    L295
  mov    -0x60(%rsp),%r11d
  mov    -0x30(%rsp),%eax
  jmp    L248
  nopl   0x0(%rax)
L258:
  sub    $0x8,%rax
  sub    -0x58(%rsp),%rax
  mov    %rdx,-0x60(%rsp)
  lea    (%rbx,%rax,1),%r15
  mov    0x38(%rsp),%edx
  mov    -0x20(%rsp),%rax
  nopl   0x0(%rax,%rax,1)
L111:
  movsd  (%r15,%rax,8),%xmm0
  mulsd  %xmm1,%xmm0
  movsd  %xmm0,(%rcx,%rax,8)
  add    $0x1,%rax
  cmp    %eax,%edx
  jg     L111
  mov    -0x60(%rsp),%rdx
  jmp    L64
```

assistant: ```c
void merge_matrix(int n1, int n2, double c_ll, const double *a_ll, double c_lh, const double *a_lh, double c_hl, const double *a_hl, double c_hh, const double *a_hh, int n, double *a) {
  int i, j;
  for (i = 0; i < n1; i++) {
    for (j = 0; j < n1; j++) {
      a[i * n + j] = c_ll * a_ll[i * n1 + j];
    }
    for (j = n1; j < n; j++) {
      a[i * n + j] = c_lh * a_lh[i * n2 + (j - n1)];
    }
  }
  for (i = n1; i < n; i++) {
    for (j = 0; j < n1; j++) {
      a[i * n + j] = c_hl * a_hl[(i - n1) * n1 + j];
    }
    for (j = n1; j < n; j++) {
      a[i * n + j] = c_hh * a_hh[(i - n1) * n2 + (j - n1)];
    }
  }
}
```