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

```asm
<split>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x78,%rsp
  mov    %rdi,0x18(%rsp)
  mov    %rsi,0x10(%rsp)
  mov    %fs:0x28,%rax
  mov    %rax,0x68(%rsp)
  mov    %rcx,%rax
  sub    %rdx,%rax
  cmp    $0x1,%rax
  jbe    L59
  mov    %rdx,%r12
  mov    %rcx,%rbx
  lea    0x10(%rsp),%rsi
  mov    %r8d,%ebp
  lea    (%rbx,%r12,1),%r13
  lea    0x18(%rsp),%rdi
  call   <swap@plt>
  shr    %r13
  mov    0x10(%rsp),%rsi
  mov    0x18(%rsp),%rdi
  mov    %r13,%rax
  sub    %r12,%rax
  mov    %rdi,0x38(%rsp)
  mov    %rsi,0x40(%rsp)
  cmp    $0x1,%rax
  jbe    L167
  lea    (%r12,%r13,1),%r14
  lea    0x40(%rsp),%rsi
  lea    0x38(%rsp),%rdi
  shr    %r14
  call   <swap@plt>
  mov    0x40(%rsp),%rsi
  mov    0x38(%rsp),%rdi
  mov    %r14,%rax
  sub    %r12,%rax
  mov    %rdi,0x48(%rsp)
  mov    %rsi,0x50(%rsp)
  cmp    $0x1,%rax
  jbe    L50
  lea    (%r12,%r14,1),%r15
  lea    0x50(%rsp),%rsi
  lea    0x48(%rsp),%rdi
  shr    %r15
  call   <swap@plt>
  mov    0x50(%rsp),%rsi
  mov    0x48(%rsp),%rdi
  mov    %r15,%rax
  sub    %r12,%rax
  mov    %rdi,0x58(%rsp)
  mov    %rsi,0x60(%rsp)
  cmp    $0x1,%rax
  jbe    L146
  lea    0x60(%rsp),%rsi
  lea    0x58(%rsp),%rdi
  call   <swap@plt>
  lea    (%r12,%r15,1),%r9
  mov    %ebp,%r8d
  mov    %r12,%rdx
  shr    %r9
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  mov    %r9,%rcx
  mov    %r9,(%rsp)
  call   <split>
  mov    (%rsp),%rdx
  mov    %ebp,%r8d
  mov    %r15,%rcx
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  call   <split>
  mov    0x60(%rsp),%rsi
  mov    %r15,%r8
  mov    %r12,%rdx
  mov    0x58(%rsp),%rdi
  mov    (%rsp),%rcx
  call   <merge@plt>
  mov    0x50(%rsp),%rsi
  mov    0x48(%rsp),%rdi
L146:
  mov    %r14,%rax
  mov    %rdi,0x58(%rsp)
  sub    %r15,%rax
  mov    %rsi,0x60(%rsp)
  cmp    $0x1,%rax
  jbe    L82
  lea    0x60(%rsp),%rsi
  lea    0x58(%rsp),%rdi
  call   <swap@plt>
  lea    (%r14,%r15,1),%r9
  mov    %ebp,%r8d
  mov    %r15,%rdx
  shr    %r9
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  mov    %r9,%rcx
  mov    %r9,(%rsp)
  call   <split>
  mov    (%rsp),%rdx
  mov    %ebp,%r8d
  mov    %r14,%rcx
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  call   <split>
  mov    0x60(%rsp),%rsi
  mov    %r14,%r8
  mov    %r15,%rdx
  mov    0x58(%rsp),%rdi
  mov    (%rsp),%rcx
  call   <merge@plt>
  mov    0x50(%rsp),%rsi
  mov    0x48(%rsp),%rdi
L82:
  mov    %r14,%r8
  mov    %r15,%rcx
  mov    %r12,%rdx
  call   <merge@plt>
  mov    0x40(%rsp),%rsi
  mov    0x38(%rsp),%rdi
L50:
  mov    %r13,%rax
  mov    %rdi,0x48(%rsp)
  sub    %r14,%rax
  mov    %rsi,0x50(%rsp)
  cmp    $0x1,%rax
  jbe    L114
  lea    0x0(%r13,%r14,1),%r15
  lea    0x50(%rsp),%rsi
  lea    0x48(%rsp),%rdi
  shr    %r15
  call   <swap@plt>
  mov    0x50(%rsp),%rsi
  mov    0x48(%rsp),%rdi
  mov    %r15,%rax
  sub    %r14,%rax
  mov    %rdi,0x58(%rsp)
  mov    %rsi,0x60(%rsp)
  cmp    $0x1,%rax
  jbe    L58
  lea    0x60(%rsp),%rsi
  lea    0x58(%rsp),%rdi
  call   <swap@plt>
  lea    (%r14,%r15,1),%r9
  mov    %ebp,%r8d
  mov    %r14,%rdx
  shr    %r9
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  mov    %r9,%rcx
  mov    %r9,(%rsp)
  call   <split>
  mov    (%rsp),%rdx
  mov    %ebp,%r8d
  mov    %r15,%rcx
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  call   <split>
  mov    0x60(%rsp),%rsi
  mov    %r15,%r8
  mov    %r14,%rdx
  mov    0x58(%rsp),%rdi
  mov    (%rsp),%rcx
  call   <merge@plt>
  mov    0x50(%rsp),%rsi
  mov    0x48(%rsp),%rdi
L58:
  mov    %r13,%rax
  mov    %rdi,0x58(%rsp)
  sub    %r15,%rax
  mov    %rsi,0x60(%rsp)
  cmp    $0x1,%rax
  jbe    L163
  lea    0x60(%rsp),%rsi
  lea    0x58(%rsp),%rdi
  call   <swap@plt>
  lea    0x0(%r13,%r15,1),%r9
  mov    %ebp,%r8d
  mov    %r15,%rdx
  shr    %r9
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  mov    %r9,%rcx
  mov    %r9,(%rsp)
  call   <split>
  mov    (%rsp),%rdx
  mov    %ebp,%r8d
  mov    %r13,%rcx
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  call   <split>
  mov    0x60(%rsp),%rsi
  mov    %r13,%r8
  mov    %r15,%rdx
  mov    0x58(%rsp),%rdi
  mov    (%rsp),%rcx
  call   <merge@plt>
  mov    0x50(%rsp),%rsi
  mov    0x48(%rsp),%rdi
L163:
  mov    %r13,%r8
  mov    %r15,%rcx
  mov    %r14,%rdx
  call   <merge@plt>
  mov    0x40(%rsp),%rsi
  mov    0x38(%rsp),%rdi
L114:
  mov    %r13,%r8
  mov    %r14,%rcx
  mov    %r12,%rdx
  call   <merge@plt>
  mov    0x10(%rsp),%rsi
  mov    0x18(%rsp),%rdi
L167:
  mov    %rbx,%rax
  mov    %rdi,0x28(%rsp)
  sub    %r13,%rax
  mov    %rsi,0x30(%rsp)
  cmp    $0x1,%rax
  jbe    L122
  lea    (%rbx,%r13,1),%r14
  lea    0x30(%rsp),%rsi
  lea    0x28(%rsp),%rdi
  shr    %r14
  call   <swap@plt>
  mov    0x30(%rsp),%rsi
  mov    0x28(%rsp),%rdi
  mov    %r14,%rax
  sub    %r13,%rax
  mov    %rdi,0x48(%rsp)
  mov    %rsi,0x50(%rsp)
  cmp    $0x1,%rax
  jbe    L27
  lea    0x0(%r13,%r14,1),%r15
  lea    0x50(%rsp),%rsi
  lea    0x48(%rsp),%rdi
  shr    %r15
  call   <swap@plt>
  mov    0x50(%rsp),%rsi
  mov    0x48(%rsp),%rdi
  mov    %r15,%rax
  sub    %r13,%rax
  mov    %rdi,0x58(%rsp)
  mov    %rsi,0x60(%rsp)
  cmp    $0x1,%rax
  jbe    L28
  lea    0x60(%rsp),%rsi
  lea    0x58(%rsp),%rdi
  call   <swap@plt>
  lea    0x0(%r13,%r15,1),%r9
  mov    %ebp,%r8d
  mov    %r13,%rdx
  shr    %r9
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  mov    %r9,%rcx
  mov    %r9,(%rsp)
  call   <split>
  mov    (%rsp),%rdx
  mov    %ebp,%r8d
  mov    %r15,%rcx
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  call   <split>
  mov    0x60(%rsp),%rsi
  mov    %r15,%r8
  mov    %r13,%rdx
  mov    0x58(%rsp),%rdi
  mov    (%rsp),%rcx
  call   <merge@plt>
  mov    0x50(%rsp),%rsi
  mov    0x48(%rsp),%rdi
L28:
  mov    %r14,%rax
  mov    %rdi,0x58(%rsp)
  sub    %r15,%rax
  mov    %rsi,0x60(%rsp)
  cmp    $0x1,%rax
  jbe    L24
  lea    0x60(%rsp),%rsi
  lea    0x58(%rsp),%rdi
  call   <swap@plt>
  lea    (%r14,%r15,1),%r9
  mov    %ebp,%r8d
  mov    %r15,%rdx
  shr    %r9
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  mov    %r9,%rcx
  mov    %r9,(%rsp)
  call   <split>
  mov    (%rsp),%rdx
  mov    %ebp,%r8d
  mov    %r14,%rcx
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  call   <split>
  mov    0x60(%rsp),%rsi
  mov    %r14,%r8
  mov    %r15,%rdx
  mov    0x58(%rsp),%rdi
  mov    (%rsp),%rcx
  call   <merge@plt>
  mov    0x50(%rsp),%rsi
  mov    0x48(%rsp),%rdi
L24:
  mov    %r14,%r8
  mov    %r15,%rcx
  mov    %r13,%rdx
  call   <merge@plt>
  mov    0x30(%rsp),%rsi
  mov    0x28(%rsp),%rdi
L27:
  mov    %rbx,%rax
  mov    %rdi,0x38(%rsp)
  sub    %r14,%rax
  mov    %rsi,0x40(%rsp)
  cmp    $0x1,%rax
  jbe    L68
  lea    (%rbx,%r14,1),%r15
  lea    0x40(%rsp),%rsi
  lea    0x38(%rsp),%rdi
  shr    %r15
  call   <swap@plt>
  mov    0x40(%rsp),%rsi
  mov    0x38(%rsp),%rdi
  mov    %r15,%rax
  sub    %r14,%rax
  mov    %rdi,0x48(%rsp)
  mov    %rsi,0x50(%rsp)
  cmp    $0x1,%rax
  jbe    L19
  lea    0x50(%rsp),%rsi
  lea    0x48(%rsp),%rdi
  call   <swap@plt>
  lea    (%r14,%r15,1),%r9
  mov    0x50(%rsp),%rsi
  mov    0x48(%rsp),%rdi
  shr    %r9
  mov    %r9,%rax
  mov    %rdi,0x58(%rsp)
  sub    %r14,%rax
  mov    %rsi,0x60(%rsp)
  cmp    $0x1,%rax
  jbe    L117
  lea    0x60(%rsp),%rsi
  lea    0x58(%rsp),%rdi
  mov    %r9,(%rsp)
  call   <swap@plt>
  mov    (%rsp),%r9
  mov    %ebp,%r8d
  mov    %r14,%rdx
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  lea    (%r14,%r9,1),%r10
  shr    %r10
  mov    %r10,%rcx
  mov    %r10,0x8(%rsp)
  call   <split>
  mov    (%rsp),%rcx
  mov    0x8(%rsp),%rdx
  mov    %ebp,%r8d
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  call   <split>
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  mov    %r14,%rdx
  mov    (%rsp),%r8
  mov    0x8(%rsp),%rcx
  call   <merge@plt>
  mov    0x50(%rsp),%rsi
  mov    0x48(%rsp),%rdi
  mov    (%rsp),%r9
L117:
  mov    %r9,%rdx
  mov    %ebp,%r8d
  mov    %r15,%rcx
  mov    %r9,(%rsp)
  call   <split>
  mov    0x50(%rsp),%rsi
  mov    %r15,%r8
  mov    %r14,%rdx
  mov    0x48(%rsp),%rdi
  mov    (%rsp),%rcx
  call   <merge@plt>
  mov    0x40(%rsp),%rsi
  mov    0x38(%rsp),%rdi
L19:
  mov    %rbx,%rax
  mov    %rdi,0x58(%rsp)
  sub    %r15,%rax
  mov    %rsi,0x60(%rsp)
  cmp    $0x1,%rax
  jbe    L21
  lea    0x60(%rsp),%rsi
  lea    0x58(%rsp),%rdi
  call   <swap@plt>
  lea    (%rbx,%r15,1),%r9
  mov    %ebp,%r8d
  mov    %r15,%rdx
  shr    %r9
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  mov    %r9,%rcx
  mov    %r9,(%rsp)
  call   <split>
  mov    (%rsp),%rdx
  mov    %ebp,%r8d
  mov    %rbx,%rcx
  mov    0x60(%rsp),%rsi
  mov    0x58(%rsp),%rdi
  call   <split>
  mov    0x60(%rsp),%rsi
  mov    %rbx,%r8
  mov    %r15,%rdx
  mov    0x58(%rsp),%rdi
  mov    (%rsp),%rcx
  call   <merge@plt>
  mov    0x40(%rsp),%rsi
  mov    0x38(%rsp),%rdi
L21:
  mov    %rbx,%r8
  mov    %r15,%rcx
  mov    %r14,%rdx
  call   <merge@plt>
  mov    0x30(%rsp),%rsi
  mov    0x28(%rsp),%rdi
L68:
  mov    %rbx,%r8
  mov    %r14,%rcx
  mov    %r13,%rdx
  call   <merge@plt>
  mov    0x10(%rsp),%rsi
  mov    0x18(%rsp),%rdi
L122:
  mov    %rbx,%r8
  mov    %r13,%rcx
  mov    %r12,%rdx
  call   <merge@plt>
L59:
  mov    0x68(%rsp),%rax
  sub    %fs:0x28,%rax
  jne    L26
  add    $0x78,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L26:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
void split(int64_t *a, int64_t *b, size_t begin, size_t end, int threshold) {
  if (end - begin < 2)
    return;
  swap(&a, &b);
  size_t mid = (begin + end) / 2;
#pragma omp task shared(a, b, threshold) firstprivate(begin, mid, end) if ((end - begin) > threshold)
  split(a, b, begin, mid, threshold);
  split(a, b, mid, end, threshold);
  merge(a, b, begin, mid, end);
#pragma omp taskwait
}
```