Arithmetic Logical Unit [8 bit]

Arithmetic Logical Unit [8 bit]

Quick Overview

Number of instructions: 4* (OR, ADD, AND, and NOT)
Number size: 8 bits
Download: schematic
*)It is possible to use another instruction: SUBtract two numbers. Thererfore, you have to do two things: first, you need to enable the carry in from the first alu slice (obsidian block on the left). Second, you need to invert the input from one of the numbers.

Overview

We adapted this design from a book called "Computer Organization" by Andrew S. Tanenbaum. This ALU uses two 8 bit unsigned numbers. The two lowest rows of levers on the control panel represent the first and second number. The upper 2 levers determine what opcode to perform on those numbers. We placed some redstone lamps on the output and on the roof.
When adding two numbers, the carry out (overflow, whatever) is on the right side of the ALU.

NOTE: we haven't had tested all possible combinations, some operations therefore may result in incorrect answers. If you are experiencing any problems, please inform us.

Known issues / Stuff to do

• Testing SUBtract routine