A machine instruction is a program or instruction in machine code. In other words, instructions are written in the machine code of the computer that it can recognize and then execute.
Machine code or machine language refers to a computer programming language consisting of a sequence of 1’s and 0’s, i.e. binary code. The computer can respond directly to the machine code, that is, without any direction or transition.
BusinessDictionary.com has the following definition of machine instructions:
“Operating instructions (programs) are written in the native code (machine code) of a machine (such as a computer or robot) that it can recognize and execute.”
A machine instruction is a program in machine language
A machine instruction consists of many bytes of memory. It tells the computer processor to perform an action on the machine. CPU stands for central processing unit.
The processor checks each machine instruction in the system’s main memory. For each machine instruction, it performs one machine operation.
A machine language program is the collection of all machine instructions in main memory. Machine instructions – four main steps
There are four main steps in the machine instruction cycle:
- Fetch: the processor fetches the instruction from the memory address. It stores the address in the PC (program counter) and IR (instruction register). PC points to the next instruction at the end of the fetch operation.
- Decoding: the processor interprets and decodes the instruction. The instruction in the IR is decoded.
- Execution: The CPU controller decodes data as a sequence of command signals to the corresponding functional units of the CPU. These units perform actions that the instructions “order”.
- Storage: The operation produces a result that the processor will store in main memory. Sometimes it can send it to an output device.
According to chortle.ccsu.edu:
“Each tiny electronic operation that a processor core can perform is called a machine operation. The processor (“machine”) performs operations one at a time, but billions of operations per second.”
Turning human instructions into machine instructions
Human programmers don’t write programs as long strings of ones and zeros or as sequences of binary digits. They use Python, BASIX, Ruby, Java, C++ or another programming language. We call these high-level programming languages.
High-level languages are more like everyday written languages that people use than binary numbers. But the computer doesn’t understand them.
Before a computer’s processor can execute instructions in a high-level language, they must be translated into binary code. In the world of computer programming, there are two languages:
- Human readable language. In this case, humans can read and understand them, but machines cannot.
- Machine readable language. They appear as long strings of 1s and 0s and tell the computer’s processor what to do. Humans cannot read language, only machines (computers) can.
Compilers and interpreters
Most programming software includes software that translates high-level language into machine instructions. We call these compilers compilers and interpreters. The compiler or interpreter interprets the language.
A compiler translates a human-readable program into a machine-readable form before the program can run.
An interpreter translates a human-readable program, guided by instructions, into a machine-readable operating form. It then executes each statement it translated before moving on to the next. Every time the program runs, it is translated.
