Project ForgeComputer Organization & Architecture
Pipelining & Instruction Sets
GATE 2015
Medium
For computers based on three-address instruction formats, each address field can be used to specify which of the following:
(S1) A memory operand (S2) A processor register (S3) An implied accumulator register
- Either S1 or S2
- BEither S2 or S3
- COnly S2 and S3
- DAll of S1, S2 and S3
Explanation
In a three-address instruction, each of the 3 address fields explicitly names an operand location — it can be a memory address (S1) or a processor register (S2). It can NOT be an 'implied' accumulator (S3), because an implied operand by definition has no explicit address field at all — that's what 'implied' means. So each address field is either S1 or S2.
Source: GATE CS 2015 (Session 1 / 7th Feb Shift 1) (2015)
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