background

In this semester, a project on the principles of computer composition, let logisim be used to build a complement array multiplier. After reading the explanation of the mooc teacher recommended by the classmates, I slowly understood it. It is very friendly to novices. The course name is Computer Hardware System. Design, attach a link hereComputer hardware system design

Specific project

Use logisim to construct a 6*6 complement array multiplier with eleven-bit output.

Implementation process and principle

Ideas: First of all, for the complement operation, the key is to changeDistinguish between sign bit and value bitIn the future, if the number is a positive number, then directly use the numeric bits to perform the corresponding operation, and then add the sign bit in front of it, but if this is a negative number, you need to deal with this numeric bit specially, and then according to the corresponding Then the logic can be transformed.
principle：
where:
1. n-bit complementer: According to the sign bit of the input 6-bit complement, we need to determine whether the 5 digits after the complement are the original value digits without the complement. This can be achieved with the 5-bit complementer in logisim.
2. AND gate array and array multiplier: Unsigned 5 * 5 array multiplier, the output is 10 bits and needs to be constructed with the corresponding AND gate array, the specific principle is as follows:

Implementation result:

3. 2n-bit complementer: Multiply two 6-bit complements, except for the sign bit, the output is 10 bits, and the result is the absolute value of the 10-bit product, so when the two's complements of different signs are multiplied, you need to use one With a 10-bit complementer, these two results can be selected with the sign bit using a multiplexer.

The realization result of the project
6 * 6's complement array multiplier:

Remarks

The original circuit and resources above can be found in the course link attached at the beginning of the article.