Skip to content
Computer Internals

Glossary

ALU (arithmetic logic unit)

The circuit inside the CPU that performs arithmetic and bitwise operations and produces the status flags.

The ALU takes two operands and an operation code, and outputs a result plus flags such as carry (CF), zero (ZF), sign (SF) and overflow (OF). A cmp instruction is simply a subtraction whose result is thrown away — only the flags are kept.