与int类型相关的数据类型

1. mr_small、mr_large

#define mr_utype int
#define mr_dltype long long

#ifdef MR_FP
  typedef mr_utype mr_small;
  #ifdef mr_dltype
  typedef mr_dltype mr_large;
  #endif
#else
  typedef unsigned mr_utype mr_small;
  #ifdef mr_dltype
    typedef unsigned mr_dltype mr_large;
  #endif
#endif

2. union doubleword

union doubleword类型中，两个mr_small类型数据构造一个mr_large类型。

union doubleword
{
    mr_large d;
    mr_small h[2];
};