About
An instruction set is the basic set of instructions (command) that a programmable device (the most known being the cpu) understands and can execute.
Instruction set is a set of instruction that represents the vocabulary of a programmable device such as:
Same as Language - Machine
The instruction set is part of the computer architecture known as the Instruction Set Architecture (ISA).
The word set refers to the set of predefined opcodes that are valid in each instruction. Each opcode is a member of the “instruction set”.
The instruction set serves as the boundary between:
- software
- and hardware.
The instruction set provides commands to the device.
An instruction set specifies a device’s functionality
- what operations it supports
- what storage mechanisms it has & how they are accessed
- how the programmer/compiler communicates programs
Different computer processors can use almost the same instruction set while still having very different internal design.
An instruction set can be:
- built into the hardware of the processor,
- or emulated in software, using an interpreter.
The more instructions (e.g. more features) a CPU has, the more circuits are required to implement it.
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Example
An example of an instruction set is the x86 instruction set. See wiki/X86_instruction_listings
| Instruction | Description |
|---|---|
| ADD | Add two numbers together. |
| COMPARE | Compare numbers. |
| IN | Input information from a device, e.g. keyboard. |
| JUMP | Jump to designated RAM address. |
| JUMP IF | Conditional statement that jumps to a designated RAM address. |
| LOAD | Load information from RAM to the CPU. |
| OUT | Output information to device, e.g. monitor. |
| STORE | Store information to RAM. |