Design the logic to control an ALU, which has the following inputs: Ainvert,Binv
ID: 3593792 • Letter: D
Question
Design the logic to control an ALU, which has the following inputs:
Ainvert,Binvert,Cin,Op1 (high bit of the 2-bit operation input),Op0 (low bit of the 2-bit operation input)
Assume that you only need to design ALU control circuitry for these six R-type instructions: add, and, nor, or, sub, slt.
a. The MIPS encoding for each of these six instructions has an opcode of 0; however, each has a different function code.
b.rovide the truth table that describes the ALU's control logic. There are exactly six inputs — the six bits of the function code (in order). Label them F5 ... F0. There are exactly five outputs — the five ALU inputs listed above.
c. Provide the Boolean algebra expression for output Binvert only. Use the truth table and sum of products to arrive at your answer.
Explanation / Answer
The truth table for the 1-bit ALU::
Select values for a, b, Ainvert, Binvert, and Less, and the result is to be checked as expected for the operation specified by the two Operation bits Op1 and Op0.
Op1 Op0 Result 0 0 a AND b 0 1 a OR b 1 0 a+b 1 1 less (0 or 1 from the result of SLT)Related Questions
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