Full Precision：完全精确
Truncate LSBs：截断低位
Non Symmetric Rounding Down：非对称向下舍入
Non Symmetric Rounding Up：非对称舍入
Symmetric Rounding to Zero：对称舍入为零
Symmetric Rounding to Infinity：对称舍入到无穷大
Convergent Rounding to Even：趋同四舍五入到均匀
Convergent Rounding to Odd：趋同四舍五入