A computer instruction refers to a binary code that controls how a computer performs micro-operations in a series. They, together with the information, are saved in the memory. Every computer has its own set of instructions. Operation codes or Opcodes and Addresses are the two elements that they are divided into.
In this article, we will dive deeper into the types of instructions in Computer Architecture according to the GATE Syllabus for (Computer Science Engineering) CSE. Keep reading ahead to learn more.
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What are the Types of Instructions in Computer Architecture?
A computer’s instructions can be any length and have any number of addresses. The arrangement of a computer’s registers determines the different address fields in the instruction format. The instruction can be classified as three, two, and one address instruction or zero address instruction, depending on the number of address fields.
Three Address Instructions
A three-address instruction has the following general format:
source 1 operation, source 2 operation, source 3 operation, destination
ADD X, Y, Z
Here, X, Y, and Z seem to be the three variables that are each assigned to a distinct memory location. The operation implemented on operands is ‘ADD.’ The source operands are ‘X’ and ‘Y,’ while the destination operand is ‘Z.’
In order to determine the three operands, bits are required. To determine one operand, n bits are required (one memory address). In the same way, 3n bits are required to define three operands (or three memory addresses). To identify the ADD operation, bits are also required.
Two Address Instructions
A two-address instruction has the following general format:
source and destination of the operation
ADD X, Y
Here X and Y are the two variables that have been assigned to a specific memory address. The operation performed on the operands is ‘ADD.’ This command combines the contents of variables X and Y and stores the result in variable Y. The source operand is ‘A,’ while ‘B’ is used as both a source and a destination operand.
The two operands must be determined using bits. To define one operand, n bits are required (one memory address). To determine two operands, 2n bits are required (two memory addresses). The ADD operation also necessitates the use of bits.
One Address Instructions
One address instruction has the following general format:
operation source
INCLUDE X
Here X refers to the variable that has access to a specific memory region. The operation performed on operand A is ‘ADD.’ This instruction adds the value of variable A to the accumulator and then saves the result inside the accumulator by restoring the accumulator’s contents.
Zero Address Instructions
In zero address instructions, the positions of the operands are implicitly represented. These instructions use a structure called a pushdown stack to hold operands.
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- Instruction Pipeline in Computer Architecture
- Memory Organization in Computer Architecture
- Pipeline Hazards in Computer Architecture
- Pipelining in Computer Architecture
- Structural Hazards in Computer Architecture
- Computer Architecture MCQs
- ALU (Arithmetic Logic Unit)
- Control Unit
- Microprogrammed Control Unit
- Instruction Formats
- Addressing Modes
- Memory Hierarchy
- Fully Associative Mapping
- Associative Mapping
- Direct Mapping
- Conversion of Bases to Other Bases
- Flynn’s Classification of Computers
- SIMD
- SISD
- MIMD
- MISD
- De Morgan’s Theorems
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