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

```asm
<merge_matrix>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %edi,-0x14(%rbp)
  mov    %esi,-0x18(%rbp)
  movsd  %xmm0,-0x20(%rbp)
  mov    %rdx,-0x28(%rbp)
  movsd  %xmm1,-0x30(%rbp)
  mov    %rcx,-0x38(%rbp)
  movsd  %xmm2,-0x40(%rbp)
  mov    %r8,-0x48(%rbp)
  movsd  %xmm3,-0x50(%rbp)
  mov    %r9,-0x58(%rbp)
  movl   $0x0,-0x8(%rbp)
  jmp    L22
L42:
  movl   $0x0,-0x4(%rbp)
  jmp    L56
L112:
  mov    -0x8(%rbp),%eax
  imul   -0x14(%rbp),%eax
  mov    %eax,%edx
  mov    -0x4(%rbp),%eax
  add    %edx,%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    -0x8(%rbp),%eax
  imul   0x10(%rbp),%eax
  mov    %eax,%edx
  mov    -0x4(%rbp),%eax
  add    %edx,%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x18(%rbp),%rax
  add    %rdx,%rax
  mulsd  -0x20(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x4(%rbp)
L56:
  mov    -0x4(%rbp),%eax
  cmp    -0x14(%rbp),%eax
  jl     L112
  mov    -0x14(%rbp),%eax
  mov    %eax,-0x4(%rbp)
  jmp    L41
L46:
  mov    -0x8(%rbp),%eax
  imul   -0x18(%rbp),%eax
  mov    %eax,%edx
  mov    -0x4(%rbp),%eax
  sub    -0x14(%rbp),%eax
  add    %edx,%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    -0x8(%rbp),%eax
  imul   0x10(%rbp),%eax
  mov    %eax,%edx
  mov    -0x4(%rbp),%eax
  add    %edx,%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x18(%rbp),%rax
  add    %rdx,%rax
  mulsd  -0x30(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x4(%rbp)
L41:
  mov    -0x4(%rbp),%eax
  cmp    0x10(%rbp),%eax
  jl     L46
  addl   $0x1,-0x8(%rbp)
L22:
  mov    -0x8(%rbp),%eax
  cmp    -0x14(%rbp),%eax
  jl     L42
  mov    -0x14(%rbp),%eax
  mov    %eax,-0x8(%rbp)
  jmp    L75
L78:
  movl   $0x0,-0x4(%rbp)
  jmp    L13
L104:
  mov    -0x8(%rbp),%eax
  sub    -0x14(%rbp),%eax
  imul   -0x14(%rbp),%eax
  mov    %eax,%edx
  mov    -0x4(%rbp),%eax
  add    %edx,%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    -0x8(%rbp),%eax
  imul   0x10(%rbp),%eax
  mov    %eax,%edx
  mov    -0x4(%rbp),%eax
  add    %edx,%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x18(%rbp),%rax
  add    %rdx,%rax
  mulsd  -0x40(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x4(%rbp)
L13:
  mov    -0x4(%rbp),%eax
  cmp    -0x14(%rbp),%eax
  jl     L104
  mov    -0x14(%rbp),%eax
  mov    %eax,-0x4(%rbp)
  jmp    L18
L82:
  mov    -0x8(%rbp),%eax
  sub    -0x14(%rbp),%eax
  imul   -0x18(%rbp),%eax
  mov    %eax,%edx
  mov    -0x4(%rbp),%eax
  sub    -0x14(%rbp),%eax
  add    %edx,%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    -0x58(%rbp),%rax
  add    %rdx,%rax
  movsd  (%rax),%xmm0
  mov    -0x8(%rbp),%eax
  imul   0x10(%rbp),%eax
  mov    %eax,%edx
  mov    -0x4(%rbp),%eax
  add    %edx,%eax
  cltq
  lea    0x0(,%rax,8),%rdx
  mov    0x18(%rbp),%rax
  add    %rdx,%rax
  mulsd  -0x50(%rbp),%xmm0
  movsd  %xmm0,(%rax)
  addl   $0x1,-0x4(%rbp)
L18:
  mov    -0x4(%rbp),%eax
  cmp    0x10(%rbp),%eax
  jl     L82
  addl   $0x1,-0x8(%rbp)
L75:
  mov    -0x8(%rbp),%eax
  cmp    0x10(%rbp),%eax
  jl     L78
  nop
  nop
  pop    %rbp
  ret
```

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)];
    }
  }
}
```