Question

This section gives you freedom to come up with your own solutions.

An Arithmetic and Logic Unit (ALU) is a combinational circuit that performs logic and arithmetic micro-operations on a pair of 4-bit operands. The operations performed by an ALU are controlled by a set of function-select inputs. In this lab you will design a 4-bit ALU with 3 function-select inputs: Mode M, Select S1 and S0 inputs. The mode input M selects between a Logic (M=0) and Arithmetic (M=1) operation.

Note that the zero and Carry flags are cleared for logical operation and are affected by the arithmetic operations only

This design project gives you freedom to come up with two different solutions. Make sure that no latches exist in the design. The two designs should be different in the structure and hardware resource requirement.

Carry in Co Carry out Cout Data in A[ 301-4 Z ( Zero flag) Data in B[3:0] 4-bit ALU Data output FI3:0] Operation select S 1 S0 select Figure 3: Block diagram of the 4-bit ALU The functions performed by the ALU are specified in Table l. Table 1: Functions of ALU M = 0 Logic S1 S0C0 FUNCTION OPERATION (bit wise) AND OR XOR Bi 1X BXNOR M- 1 Arithmetio S1 S0 CO FUNCTION OPERATION A B+ Carry in A+BCin +not B B (ones complement) Subtract A from B (i.e. BA+ 1) Two's co

Answer 1

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