GATE 2024 CS (CS2) – Question 57

Computer Organization and Architecture · Instruction Set and Addressing Modes · 2 marks · Numerical answer

A processor with 16 general purpose registers uses a 32-bit instruction format. The instruction format consists of an opcode field, an addressing mode field, two register operand fields, and a 16-bit scalar field. If 8 addressing modes are to be supported, the maximum number of unique opcodes possible for every addressing mode is _________

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Correct answer: 32

Explanation

Bits: addressing mode 3, two registers 4+4 = 8, scalar 16. Opcode bits = 32 − 3 − 8 − 16 = 5, giving 2^5 = 32 opcodes.