直接补码阵列乘法的手工计算方法

Manual Computing Method with Direct 2′s Complement Array Multiplier

直接补码阵列乘法器的工作原理是《计算机组成原理》课程的难点。教材在介绍定点数乘法时包括3种乘法器电路,其中在直接补码阵列乘法器中,被乘数和乘数均采用补码表示,符号位一起参加运算,积也采用补码形式表示。文中从补码与真值的关系出发,结合一般化的全加器形式,说明负权参加运算时的特征,并介绍如何将出现在数值位中的负权值在不改变真值的情况下向左移动,直至符号位。通过4种情况给出4个实例,说明使用直接补码阵列乘法的手工计算方法,从而揭示出直接补码阵列乘法器的工作原理。

The direct 2＇s complement array multiplier principle of work is the curriculum difficulty of “Computer Organization Principle” Teaching materials introduces three kinds of multiplier electric circuits about fixed point number multiplication, and in the direct 2＇s complement array multiplier, the multiplication and the multiplication are all expressed with the 2＇s complement, and the sign bit participate to operate together. This article starts from the 2＇s complement and the true value relations, unions generalization full adder form, and shows the characteristic of negative power participation operation. And introduces the method that the negative weight bit move towards left without changing the true value till the sign bit. In this article gives four cases for four situation to explain the manual computing method . At the last , it promulgates the direct 2% complement array multiplier the principle of work.