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Now that we have some idea of how instructions are encoded, we can begin designing the instruction set for our CPU, starting with the ALU.

## ALU Instructions

Arithmetic and Logic Instructions such as addition, subtraction, logical OR/AND, as well as comparison operations _(which are typically just variations of SUB or AND instructions that don’t write their output)_, are often grouped into a separate part of the CPU circuit called the Arithmetic Logic Unit, or ALU.

[Continue reading here...](https://medium.com/the-ember-project/the-ember-cpu-initial-design-part-4-arithmetic-logic-unit-alu-d54ff68a6134)