package bit_rtl_pkg is--包头(包说明)subtype short is integer range 0 to 66535;--short 为数据子类型,是整数的一部分subtype int4 is integer range 0 to 16;subtype int8 is integer range 0 to 255;--以下均为函数头,具体定义见包体function bit_to_int (in1:bit_vector) return integer;function "+" (in1,in2 : bit_vector) return integer;function "-" (in1,in2 : bit_vector) return integer;function "*" (in1,in2 : bit_vector) return bit_vector;function "/" (in1,in2 : bit_vector) return bit_vector;end bit_rtl_pkg;
package body bit_rtl_pkg is
--包体,由关键字package body标识
--函数bit_to_int将为向量转化为十进制整数值
function bit_to_int (in1 : bit_vector) re