The Z-80 has a 4-bit ALU. Here's how it works.
4-bit CPU
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Design and Simulation of a Pipelined 4 bit Computer
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2. Consider the 4-bit CPU architecture given below. | Chegg.com
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Architecture
computer architecture - How can I get 8 bits output from 4 bit CPU? - Computer Science Stack Exchange
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Figure 4 from Simple 4-bit processor based on quantum-dot cellular automata (QCA) | Semantic Scholar
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Nibbler 4 Bit CPU | Big Mess o' Wires
