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

```asm
<iterative_merge>:
  endbr64
  push   %r15
  mov    %rsi,%r11
  push   %r14
  shr    %r11
  push   %r13
  mov    %rdi,%r13
  mov    %r11d,%edi
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x38,%rsp
  mov    %r11,0x10(%rsp)
  mov    %rsi,(%rsp)
  call   <log@plt>
  mov    $0x2,%edi
  mov    %eax,%ebx
  call   <log@plt>
  mov    %eax,%r8d
  mov    %ebx,%eax
  cltd
  idiv   %r8d
  mov    %eax,%edi
  call   <floor@plt>
  mov    $0x2,%edi
  mov    %eax,%esi
  call   <pow@plt>
  movslq %eax,%rdx
  mov    (%rsp),%rax
  lea    (%rdx,%rdx,1),%esi
  movslq %esi,%rsi
  sub    %rsi,%rax
  cmp    %rdx,%rax
  cmovb  %rdx,%rax
  lea    0x0(,%rax,4),%r12d
  mov    %r12d,%edi
  call   <malloc@plt>
  xor    %esi,%esi
  mov    %r12d,%edx
  mov    %rax,%rdi
  mov    %rax,%r15
  call   <memset@plt>
  mov    (%rsp),%rcx
  lea    0x4(%r13),%rax
  mov    0x10(%rsp),%r11
  mov    %rax,0x8(%rsp)
  mov    $0x1,%r8d
  mov    $0x1,%r10d
  cmp    $0x1,%rcx
  lea    -0x1(%rcx),%r9d
  jbe    L42
  nopw   0x0(%rax,%rax,1)
L99:
  cmp    %r10,%r11
  jb     L100
  lea    -0x1(%r8),%r12d
  mov    %r8d,%ebp
  lea    (%r12,%r8,1),%r14d
L43:
  mov    %rcx,%rdi
  xor    %ebx,%ebx
  mov    %r15,%rcx
  xor    %eax,%eax
  mov    %rdi,%r15
  nopl   0x0(%rax)
L40:
  sub    %eax,%r12d
  cmp    %r10,%r11
  jae    L117
L119:
  test   %r12d,%r12d
  js     L115
  cmp    %r14d,%ebp
  jg     L60
  add    $0x1,%ebx
  xor    %edx,%edx
  movslq %ebx,%rax
  jmp    L10
  nopl   0x0(%rax)
L53:
  mov    %esi,-0x4(%r13,%rax,4)
  add    $0x1,%ebp
  mov    %eax,%ebx
  cmp    %r12d,%edx
  jg     L115
L59:
  add    $0x1,%rax
  cmp    %r14d,%ebp
  jg     L49
L10:
  movslq %ebp,%rsi
  movslq %edx,%rdi
  mov    0x0(%r13,%rsi,4),%esi
  mov    (%rcx,%rdi,4),%edi
  cmp    %edi,%esi
  jl     L53
  mov    %edi,%esi
  add    $0x1,%edx
  mov    %eax,%ebx
  mov    %esi,-0x4(%r13,%rax,4)
  cmp    %r12d,%edx
  jle    L59
L115:
  mov    %ebp,%eax
  cmp    %r14d,%ebp
  jg     L129
  mov    %r14d,%edx
  movslq %ebp,%rdi
  mov    0x8(%rsp),%rsi
  sub    %ebp,%edx
  lea    0x0(%r13,%rdi,4),%rax
  add    %rdi,%rdx
  lea    (%rsi,%rdx,4),%rsi
  movslq %ebx,%rdx
  sub    %rdi,%rdx
  nopl   (%rax)
L118:
  mov    (%rax),%edi
  mov    %edi,(%rax,%rdx,4)
  add    $0x4,%rax
  cmp    %rax,%rsi
  jne    L118
  lea    0x1(%r14),%eax
  add    %eax,%ebx
  sub    %ebp,%ebx
L129:
  lea    (%r8,%rax,1),%ebp
  movslq %ebp,%rdx
  cmp    %r15,%rdx
  cmovae %r9d,%ebp
  lea    -0x1(%rbp),%r12d
  lea    (%r12,%r8,1),%r14d
  movslq %r14d,%rdx
  cmp    %r15,%rdx
  movslq %ebx,%rdx
  cmovae %r9d,%r14d
  cmp    %r15,%rdx
  jb     L40
  add    %r8d,%r8d
  mov    %r15,%rax
  mov    %rcx,%r15
  movslq %r8d,%r10
  mov    %rax,%rcx
  cmp    %rax,%r10
  jb     L99
L42:
  add    $0x38,%rsp
  mov    %r15,%rdi
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  jmp    10c0 <free@plt>
L60:
  xor    %edx,%edx
  nopw   0x0(%rax,%rax,1)
L49:
  movslq %edx,%rsi
  movslq %ebx,%rdi
  mov    %edx,(%rsp)
  shl    $0x2,%rsi
  shl    $0x2,%rdi
  sub    %rsi,%rdi
  lea    (%rcx,%rsi,1),%rax
  mov    %edx,%esi
  sub    %rcx,%rdi
  add    %r13,%rdi
L132:
  mov    (%rax),%edx
  add    $0x1,%esi
  mov    %edx,(%rdi,%rax,1)
  add    $0x4,%rax
  cmp    %r12d,%esi
  jle    L132
  mov    (%rsp),%edx
  mov    %r12d,%eax
  sub    %edx,%eax
  cmp    %r12d,%edx
  mov    $0x0,%edx
  cmovg  %edx,%eax
  lea    0x1(%rbx,%rax,1),%ebx
  jmp    L115
  nopl   (%rax)
L117:
  cltq
  mov    %rcx,%rdi
  mov    %r9d,0x28(%rsp)
  lea    0x4(,%r12,4),%edx
  lea    0x0(%r13,%rax,4),%rsi
  mov    %r8d,0x24(%rsp)
  mov    %r10,0x18(%rsp)
  mov    %r11,0x10(%rsp)
  mov    %rcx,(%rsp)
  call   <memcpy@plt>
  mov    0x28(%rsp),%r9d
  mov    0x24(%rsp),%r8d
  mov    0x18(%rsp),%r10
  mov    0x10(%rsp),%r11
  mov    (%rsp),%rcx
  jmp    L119
L100:
  mov    %rcx,%rbx
  mov    %ecx,%ebp
  lea    0x0(%r13,%r10,4),%rsi
  mov    %r15,%rdi
  sub    %r10,%rbx
  sub    %r8d,%ebp
  mov    %r11,0x28(%rsp)
  mov    %r9d,%r14d
  lea    0x0(,%rbx,4),%edx
  mov    %r8d,0x24(%rsp)
  lea    -0x1(%rbp),%r12d
  mov    %r9d,0x18(%rsp)
  mov    %rcx,0x10(%rsp)
  mov    %r10,(%rsp)
  call   <memcpy@plt>
  mov    (%rsp),%r10
  lea    0x0(%r13,%rbx,4),%rdi
  mov    %r13,%rsi
  lea    0x0(,%r10,4),%edx
  call   <memmove@plt>
  mov    (%rsp),%r10
  mov    0x10(%rsp),%rcx
  mov    0x18(%rsp),%r9d
  mov    0x24(%rsp),%r8d
  mov    0x28(%rsp),%r11
  jmp    L43
```

assistant: ```c
void iterative_merge(int a[], size_t n) {
  int t = pow(2, floor(log(n / 2) / log(2)));
  int tempsize = (t > n - 2 * t) ? t : n - 2 * t;
  int *temparray = (int *)malloc(tempsize * sizeof(int));
  memset(temparray, 0, tempsize * sizeof(int));
  int l, l_max, r, r_max, incr, i, j, cpy_size;
  incr = 1;
  while (incr < n) {
    if (incr <= n / 2) {
      l = 0;
      r = incr;
      l_max = r - 1;
      r_max = l_max + incr;
    } else {
      l = 0;
      r = n - incr;
      l_max = r - 1;
      r_max = n - 1;
      memcpy(temparray, &a[incr], (n - incr) * sizeof(int));
      memmove(&a[n - incr], &a[0], incr * sizeof(int));
    }
    i = j = 0;
    while (i < n) {
      if (incr <= n / 2) {
        cpy_size = l_max - l + 1;
        memcpy(temparray, &a[l], cpy_size * sizeof(int));
      }
      j = 0;
      while (j <= l_max - l && r <= r_max) {
        if (a[r] < temparray[j]) {
          a[i] = a[r++];
        } else {
          a[i] = temparray[j++];
        }
        ++i;
      }
      while (j <= l_max - l) {
        a[i++] = temparray[j++];
      }
      while (r <= r_max) {
        a[i++] = a[r++];
      }
      l = r;
      r = (r + incr < n) ? r + incr : n - 1;
      l_max = r - 1;
      r_max = (l_max + incr < n) ? l_max + incr : n - 1;
    }
    incr *= 2;
  }
  free(temparray);
  return;
}
```