In terms of its basic pieces, the instruction format explains the internal structures or layout design of the instruction bits. An opcode must be included in an instruction format, and the address is reliant on the availability of specific operands.
In this article, we will dive deeper into Instruction Formats according to the GATE Syllabus for (Computer Science Engineering) CSE. Keep reading ahead to learn more.
Table of Contents
What are Instruction Formats?
A collection of operation codes, as well as operands that handle the operation codes, are included in the instruction. The bit design in an instruction is supported by the instruction format. The operands, opcode, and addressing mode are among the fields.
In most cases, the instruction length is kept in multiples of the length of the character, which is 8 bits. Several bits are assigned to the operands, opcode, and addressing modes whenever the instruction length is fixed.
Interpretation
The following factors can be used to interpret the function of the allocating bits in the instruction:
- The number of different addressing modes
- Count of operands
- The total number of address lines
- The total number of register sets
- The total number of CPU registers
The Intel Architecture – 32 bits (or IA-32) instruction format was shown in the diagram. Intel’s most advanced microprocessors use the IA-32 instruction format. The addressing mode field, opcode field, displacement field, and immediate field are all included in this instruction structure.
The opcode field consists of 1 or 2 bytes. 1 or 2 bytes are also included in the addressing mode field. If an instruction uses just one register for generating the effective address of an operand, it only needs one byte in the addressing mode field.
The displacement field is the field that comes after the addressing mode field. If the displacement value is used to compute an effective address for a memory operand, one or four bytes are used to encode. When an operand is just an immediate value, it will show in the immediate field and will be 1 or 4 bytes long.
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Also Explore,
- Types of Instructions in Computer Architecture
- ALU (Arithmetic Logic Unit)
- Control Unit
- Microprogrammed Control Unit
- 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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