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

```asm
<mergesort>:
  endbr64
  cmp    %edx,%esi
  jl     L89
  xor    %eax,%eax
  ret
  nopl   0x0(%rax,%rax,1)
L89:
  mov    %edx,%eax
  push   %r15
  xor    %r15d,%r15d
  sub    %esi,%eax
  push   %r14
  mov    %eax,%r14d
  push   %r13
  mov    %rdi,%r13
  push   %r12
  sar    %r14d
  mov    %edx,%r12d
  push   %rbp
  add    %esi,%r14d
  mov    %esi,%ebp
  push   %rbx
  xor    %ebx,%ebx
  sub    $0x18,%rsp
  cmp    %r14d,%esi
  jl     L122
  add    $0x1,%r14d
  cmp    %r12d,%r14d
  jl     L60
L52:
  mov    %r12d,%ecx
  mov    %r14d,%edx
  mov    %ebp,%esi
  mov    %r13,%rdi
  call   <merge@plt>
  add    $0x18,%rsp
  add    %ebx,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopw   0x0(%rax,%rax,1)
L122:
  mov    %eax,%ecx
  sar    $0x2,%ecx
  add    %esi,%ecx
  cmp    %ecx,%esi
  jl     L34
L96:
  lea    0x1(%rcx),%r8d
  cmp    %r8d,%r14d
  jg     L16
L13:
  mov    %r14d,%ecx
  mov    %r8d,%edx
  mov    %ebp,%esi
  mov    %r13,%rdi
  call   <merge@plt>
  add    $0x1,%r14d
  add    %eax,%ebx
  mov    %ebx,%r15d
  cmp    %r12d,%r14d
  jge    L52
L60:
  mov    %r12d,%eax
  xor    %ebx,%ebx
  xor    %r8d,%r8d
  sub    %r14d,%eax
  mov    %eax,%ecx
  sar    %ecx
  add    %r14d,%ecx
  cmp    %ecx,%r14d
  jl     L121
L24:
  lea    0x1(%rcx),%r9d
  cmp    %r9d,%r12d
  jg     L70
L87:
  mov    %r12d,%ecx
  mov    %r9d,%edx
  mov    %r14d,%esi
  mov    %r13,%rdi
  call   <merge@plt>
  add    %eax,%ebx
  add    %r15d,%ebx
  jmp    L52
  nopl   (%rax)
L34:
  sar    $0x3,%eax
  mov    %ecx,(%rsp)
  lea    (%rax,%rsi,1),%r15d
  mov    %r15d,%edx
  add    $0x1,%r15d
  call   <mergesort>
  mov    (%rsp),%edx
  mov    %r15d,%esi
  mov    %r13,%rdi
  mov    %eax,%ebx
  call   <mergesort>
  mov    (%rsp),%ecx
  mov    %r15d,%edx
  mov    %ebp,%esi
  mov    %r13,%rdi
  add    %eax,%ebx
  call   <merge@plt>
  mov    (%rsp),%ecx
  add    %eax,%ebx
  mov    %ebx,%r15d
  jmp    L96
  nopl   (%rax)
L70:
  mov    %r12d,%r10d
  mov    %r9d,%esi
  mov    %r13,%rdi
  mov    %r8d,0xc(%rsp)
  sub    %r9d,%r10d
  mov    %r9d,0x8(%rsp)
  sar    %r10d
  lea    (%r10,%r9,1),%ebx
  mov    %ebx,%edx
  call   <mergesort>
  lea    0x1(%rbx),%r10d
  mov    %r12d,%edx
  mov    %r13,%rdi
  mov    %r10d,%esi
  mov    %r10d,0x4(%rsp)
  mov    %eax,(%rsp)
  call   <mergesort>
  mov    0x8(%rsp),%r9d
  mov    (%rsp),%ebx
  mov    %r12d,%ecx
  mov    0x4(%rsp),%edx
  mov    %r13,%rdi
  mov    %r9d,%esi
  mov    %r9d,(%rsp)
  add    %eax,%ebx
  call   <merge@plt>
  mov    0xc(%rsp),%r8d
  mov    (%rsp),%r9d
  add    %eax,%ebx
  add    %r8d,%ebx
  jmp    L87
  nopl   0x0(%rax)
L121:
  sar    $0x2,%eax
  mov    %r14d,%esi
  mov    %r13,%rdi
  mov    %ecx,0x4(%rsp)
  lea    (%rax,%r14,1),%ebx
  mov    %ebx,%edx
  call   <mergesort>
  mov    0x4(%rsp),%ecx
  lea    0x1(%rbx),%r8d
  mov    %r13,%rdi
  mov    %r8d,%esi
  mov    %r8d,0x4(%rsp)
  mov    %ecx,%edx
  mov    %ecx,0x8(%rsp)
  mov    %eax,(%rsp)
  call   <mergesort>
  mov    (%rsp),%ebx
  mov    0x8(%rsp),%ecx
  mov    %r14d,%esi
  mov    0x4(%rsp),%edx
  mov    %r13,%rdi
  mov    %ecx,(%rsp)
  add    %eax,%ebx
  call   <merge@plt>
  mov    (%rsp),%ecx
  add    %eax,%ebx
  mov    %ebx,%r8d
  jmp    L24
  nopl   0x0(%rax)
L16:
  mov    %r14d,%r9d
  mov    %r8d,%esi
  mov    %r13,%rdi
  mov    %r8d,0x8(%rsp)
  sub    %r8d,%r9d
  sar    %r9d
  lea    (%r9,%r8,1),%ebx
  mov    %ebx,%edx
  call   <mergesort>
  lea    0x1(%rbx),%r9d
  mov    %r14d,%edx
  mov    %r13,%rdi
  mov    %r9d,%esi
  mov    %r9d,0x4(%rsp)
  mov    %eax,(%rsp)
  call   <mergesort>
  mov    0x8(%rsp),%r8d
  mov    (%rsp),%ebx
  mov    %r14d,%ecx
  mov    0x4(%rsp),%edx
  mov    %r13,%rdi
  mov    %r8d,%esi
  mov    %r8d,(%rsp)
  add    %eax,%ebx
  call   <merge@plt>
  mov    (%rsp),%r8d
  add    %eax,%ebx
  add    %r15d,%ebx
  jmp    L13
```

assistant: ```c
int mergesort(int arr[], int low, int high) {
  int invCount = 0;
  if (low < high) {
    int mid = low + (high - low) / 2;
    invCount = mergesort(arr, low, mid);
    invCount += mergesort(arr, mid + 1, high);
    invCount += merge(arr, low, mid + 1, high);
  }
  return invCount;
}
```