Operand will be adjusted to the number of digits indicated by the digits parameter. 操作数的小数位数调整为位数参数指示的位数。
If the value is negative, then the way that the "sign bit" is handled in a number of the bitwise operations is machine-dependent. 如果操作数为负数,则位操作符如何处理其操作数的符号位依赖于机器。