MiHonorRangeStraddleRequirement

INT64 __fastcall MiHonorRangeStraddleRequirement(INT64 a1, INT64 a2, INT64 a3, INT64 a4){
  INT64 v4; 
  INT64 result; 
  v4 = ~(a3 - 1);
  result = v4 & (a1 + a2 - 1);
  if( result == (a1 & v4) )
    return a1;
  if( (_DWORD)a4 )
    result -= a2;
  return result;
}

Referenced by:

MiFindEmptyAddressRangeDownTree
MiFindEmptyAddressRangeInTree