Prerequisite – Instruction Formats
1. Three-Address Instructions:
Three-address instruction is a format of machine instruction. It has one opcode and three address fields.
2. One-Address Instructions:
One-Address instruction is also a format. It has only two fields. One for opcode and other for operand.
Difference between Three-Address Instruction and One-Address Instruction:
|Three-Address Instruction||One-Address Instruction|
|It has four fields.||It has only two fields.|
|It has one field for opcode and three fields for address.||It also has one field for opcode but there is only one field for address.|
|It has long instruction length.||It has shorter instruction.|
|There may be three memory accesses needed for an instruction.||There is a single memory access needed for an instruction.|
|It is slower accessing location inside processor than memory.||It is faster accessing location inside processor than memory.|
|It disadvantage i.e. three memory access is eliminated by two-address memory.||It eliminated two memory access.|
|There are three location for operand and result.||There is only one location for operand and result.|
Attention reader! Don’t stop learning now. Get hold of all the important CS Theory concepts for SDE interviews with the CS Theory Course at a student-friendly price and become industry ready.