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

```asm
<CollatePixelsIntoRegions>:
  endbr64
  mov    %esi,%r8d
  mov    %edx,%esi
  mov    %ecx,%edx
  mov    (%rdi),%ecx
  mov    $0x3,%eax
  cmp    %ecx,%edx
  jbe    L544
  mov    $0x2,%eax
  cmp    %ecx,%esi
  jae    L472
L544:
  mov    0x4(%rdi),%ecx
  cmp    %edx,%ecx
  jb     L108
  or     $0xc,%eax
L32:
  mov    0x8(%rdi),%ecx
  cmp    %edx,%ecx
  jb     L96
L466:
  or     $0x30,%eax
L92:
  mov    0xc(%rdi),%ecx
  cmp    %ecx,%edx
  ja     L179
L408:
  or     $0xc0,%al
L198:
  mov    0x10(%rdi),%ecx
  cmp    %ecx,%edx
  ja     L186
L338:
  or     $0x3,%ah
L484:
  mov    0x14(%rdi),%ecx
  cmp    %ecx,%edx
  ja     L436
L19:
  or     $0xc,%ah
L448:
  mov    0x18(%rdi),%ecx
  cmp    %ecx,%edx
  ja     L117
L218:
  or     $0x30,%ah
L568:
  mov    0x1c(%rdi),%ecx
  cmp    %ecx,%edx
  ja     L365
L388:
  or     $0xc0,%ah
L5:
  mov    0x20(%rdi),%ecx
  cmp    %ecx,%edx
  ja     L410
L249:
  or     $0x30000,%eax
L195:
  mov    0x24(%rdi),%ecx
  cmp    %ecx,%edx
  ja     L46
L589:
  or     $0xc0000,%eax
L371:
  mov    0x28(%rdi),%ecx
  cmp    %ecx,%edx
  ja     L507
L531:
  or     $0x300000,%eax
L353:
  mov    0x2c(%rdi),%ecx
  cmp    %ecx,%edx
  ja     L155
L243:
  or     $0xc00000,%eax
L354:
  mov    0x30(%rdi),%ecx
  cmp    %ecx,%edx
  jbe    L101
L13:
  cmp    %ecx,%esi
  jae    L286
  mov    0x34(%rdi),%ecx
  or     $0x2000000,%eax
  cmp    %ecx,%edx
  ja     L240
L11:
  or     $0xc000000,%eax
L3:
  mov    0x38(%rdi),%ecx
  cmp    %ecx,%edx
  jbe    L217
L517:
  cmp    %ecx,%esi
  jae    L403
  mov    0x3c(%rdi),%ecx
  or     $0x20000000,%eax
  cmp    %ecx,%edx
  ja     L275
L285:
  or     $0xc0000000,%eax
  ret
  nopl   (%rax)
L108:
  cmp    %esi,%ecx
  jbe    L535
  mov    0x8(%rdi),%ecx
  or     $0x8,%eax
  cmp    %edx,%ecx
  jae    L466
L96:
  cmp    %esi,%ecx
  jbe    L73
  mov    0xc(%rdi),%ecx
  or     $0x20,%eax
  cmp    %ecx,%edx
  jbe    L408
L179:
  cmp    %ecx,%esi
  jae    L214
  mov    0x10(%rdi),%ecx
  or     $0x80,%al
  cmp    %ecx,%edx
  jbe    L338
L186:
  cmp    %ecx,%esi
  jae    L135
  mov    0x14(%rdi),%ecx
  or     $0x2,%ah
  cmp    %ecx,%edx
  jbe    L19
L436:
  cmp    %ecx,%esi
  jae    L392
  mov    0x18(%rdi),%ecx
  or     $0x8,%ah
  cmp    %ecx,%edx
  jbe    L218
L117:
  cmp    %ecx,%esi
  jae    L85
  mov    0x1c(%rdi),%ecx
  or     $0x20,%ah
  cmp    %ecx,%edx
  jbe    L388
L365:
  cmp    %ecx,%esi
  jae    L579
  mov    0x20(%rdi),%ecx
  or     $0x80,%ah
  cmp    %ecx,%edx
  jbe    L249
L410:
  cmp    %ecx,%esi
  jae    L575
  mov    0x24(%rdi),%ecx
  or     $0x20000,%eax
  cmp    %ecx,%edx
  jbe    L589
L46:
  cmp    %ecx,%esi
  jae    L262
  mov    0x28(%rdi),%ecx
  or     $0x80000,%eax
  cmp    %ecx,%edx
  jbe    L531
L507:
  cmp    %ecx,%esi
  jae    L39
  mov    0x2c(%rdi),%ecx
  or     $0x200000,%eax
  cmp    %ecx,%edx
  jbe    L243
L155:
  cmp    %ecx,%esi
  jae    L536
  mov    0x30(%rdi),%ecx
  or     $0x800000,%eax
  cmp    %ecx,%edx
  ja     L13
L101:
  or     $0x3000000,%eax
L166:
  mov    0x34(%rdi),%ecx
  cmp    %ecx,%edx
  jbe    L11
L240:
  cmp    %ecx,%esi
  jae    L511
  mov    0x38(%rdi),%ecx
  or     $0x8000000,%eax
  cmp    %ecx,%edx
  ja     L517
L217:
  or     $0x30000000,%eax
L178:
  mov    0x3c(%rdi),%ecx
  cmp    %ecx,%edx
  jbe    L285
L275:
  cmp    %ecx,%esi
  jae    L537
  or     $0x80000000,%eax
  ret
  nopl   0x0(%rax,%rax,1)
L537:
  mov    %eax,%edx
  or     $0x40000000,%edx
  cmp    %ecx,%r8d
  cmovb  %edx,%eax
  ret
  nopw   0x0(%rax,%rax,1)
L575:
  mov    %eax,%r9d
  or     $0x10000,%r9d
  cmp    %ecx,%r8d
  cmovb  %r9d,%eax
  jmp    L195
  cs nopw 0x0(%rax,%rax,1)
L85:
  mov    %eax,%r9d
  or     $0x1000,%r9d
  cmp    %ecx,%r8d
  cmovb  %r9d,%eax
  jmp    L568
  cs nopw 0x0(%rax,%rax,1)
L579:
  mov    %eax,%r9d
  or     $0x4000,%r9d
  cmp    %ecx,%r8d
  cmovb  %r9d,%eax
  jmp    L5
  cs nopw 0x0(%rax,%rax,1)
L73:
  mov    %eax,%r9d
  or     $0x10,%r9d
  cmp    %r8d,%ecx
  cmova  %r9d,%eax
  jmp    L92
  nopl   0x0(%rax,%rax,1)
L214:
  mov    %eax,%r9d
  or     $0x40,%r9d
  cmp    %ecx,%r8d
  cmovb  %r9d,%eax
  jmp    L198
  nopl   0x0(%rax,%rax,1)
L135:
  mov    %eax,%r9d
  or     $0x100,%r9d
  cmp    %ecx,%r8d
  cmovb  %r9d,%eax
  jmp    L484
  cs nopw 0x0(%rax,%rax,1)
L392:
  mov    %eax,%r9d
  or     $0x400,%r9d
  cmp    %ecx,%r8d
  cmovb  %r9d,%eax
  jmp    L448
  cs nopw 0x0(%rax,%rax,1)
L262:
  mov    %eax,%r9d
  or     $0x40000,%r9d
  cmp    %ecx,%r8d
  cmovb  %r9d,%eax
  jmp    L371
  cs nopw 0x0(%rax,%rax,1)
L403:
  mov    %eax,%r9d
  or     $0x10000000,%r9d
  cmp    %ecx,%r8d
  cmovb  %r9d,%eax
  jmp    L178
  cs nopw 0x0(%rax,%rax,1)
L39:
  mov    %eax,%r9d
  or     $0x100000,%r9d
  cmp    %ecx,%r8d
  cmovb  %r9d,%eax
  jmp    L353
  cs nopw 0x0(%rax,%rax,1)
L536:
  mov    %eax,%r9d
  or     $0x400000,%r9d
  cmp    %ecx,%r8d
  cmovb  %r9d,%eax
  jmp    L354
  cs nopw 0x0(%rax,%rax,1)
L511:
  mov    %eax,%r9d
  or     $0x4000000,%r9d
  cmp    %ecx,%r8d
  cmovb  %r9d,%eax
  jmp    L3
  cs nopw 0x0(%rax,%rax,1)
L535:
  mov    %eax,%r9d
  or     $0x4,%r9d
  cmp    %r8d,%ecx
  cmova  %r9d,%eax
  jmp    L32
  nopl   0x0(%rax,%rax,1)
L286:
  mov    %eax,%r9d
  or     $0x1000000,%r9d
  cmp    %ecx,%r8d
  cmovb  %r9d,%eax
  jmp    L166
  xchg   %ax,%ax
L472:
  xor    %eax,%eax
  cmp    %ecx,%r8d
  setb   %al
  jmp    L544
```

assistant: ```c
unsigned int CollatePixelsIntoRegions(unsigned int (*pY)[4][4], unsigned int medLowLumaStart, unsigned int medHighLumaStart, unsigned int highLumaStart) {
  int row, col;
  unsigned int luma;
  unsigned int bitMask = 0x00000003;
  unsigned int bitIndices = 0;
  for (row = 0; row < 4; row++) {
    for (col = 0; col < 4; col++) {
      luma = (*pY)[row][col];
      if (luma >= highLumaStart) {
        bitIndices |= (bitMask & 0xFFFFFFFF);
      } else if (luma > medHighLumaStart) {
        bitIndices |= (bitMask & 0xAAAAAAAA);
      } else if (luma > medLowLumaStart) {
        bitIndices |= (bitMask & 0x55555555);
      } else {
      }
      bitMask <<= 2;
    }
  }
  return bitIndices;
}
```