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Codiode/Problems/Combinational Logic

Two's Complement Subtraction via Addition

MediumLogic CircuitAnalyze

Modern arithmetic logic units perform both addition and subtraction using a single adder block to save silicon area. The operation A - B is executed by negating B and performing the addition A + (-B). This unifies the hardware path for all basic linear arithmetic.

The system under analysis uses 8-bit two's complement arithmetic. The operation to evaluate is 23 - 47.

Encode the operands into 8-bit binary. Determine the two's complement of the subtrahend. Perform the binary addition and interpret the final 8-bit result.

Constraints

  • All values must be represented exactly in 8-bit two's complement binary.
  • The addition step must be performed purely in binary to simulate the hardware adder.

Topics

arithmetictwos-complementalu-design

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