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東京大学 情報理工学系研究科 創造情報学専攻 2009年8月実施 筆記試験 第3問

Author

itsuitsuki

Description (English)

Design a multiplier whose inputs are two 3-bit numbers and the output is a 6-bit number according to the following steps.

(1) Show the truth-table of the full adder and the half adder shown in Figure 1. Then construct them using AND, OR and NOT gates.

(2) Design the 4-bit adder shown in Figure 2 using the adders designed in question (1) with additional AND, OR and NOT gates.

(3) Design a 3-bit by 3-bit multiplier that produces 6-bit output using adders from (1) and (2) with additional AND, OR and NOT gates. Inputs for the multiplier are two unsigned 3-bit integers and the output is an unsigned 6-bit integer as shown in Figure 3.

(4) Design a 3-bit by 3-bit multiplier that produces 6-bit output using adders from (1) and (2) with additional AND, OR and NOT gates. The inputs of the multiplier are two signed 3-bit integers and the output is a signed 6-bit integer as shown in Figure 4. Two's complement numbers are used both in inputs and the output numbers.

(5) Describe the construction of an -bit by -bit multiplier whose computation time is .