handelc中的关键字signal

关键字：signal

英文介绍：

A signal is an object that takes on the value assigned to it but only for that clock cycle. The value is

assigned at the start of the clock cycle and can be read back during the same clock cycle.  At all other

times the signal  takes on its initialization value. The optional disambiguator <> can be used to clarify

complex signal definitions.

signal声明的变量很特殊， 只在被赋值的那个时钟保持被赋的值，在其他时钟会变回他的初始值。

程序例子：

       int 15 a, b;

      static signal <int> sig = 690;

      a = 7;

      par

    {

          sig = a;

          b = sig; // 这时候sig的值是7.

     }

      a = sig;     // 这时候sig的值是690