Question

Explain ALU of 8085 Micro-processor with suitable diagram.

Answer 1

The organization of arithmetic and logic unit is shown in figure.

1) The arithmetic and logic unit is 8-bit unit.
2) It performs arithmetic, logic and rotate operations.
3) It consists of binary adder to perform addition and subtraction by 2’s complement method.
4) The result is typically stored in accumulator.
5) Accumulator, temporary register and flag register are closely associated with A.L.U.
6) The temporary register is used to hold data during an arithmetic/ logic operation.
7) The flags are set or reset according to the result of operations in status register.