Computer composition principle-Reading Notes (4) Instruction System

Low level of commands in computer systems:

It is a major indicator of the division between software and hardware.

It is the interface between hardware designers and software designers and a bridge between them.

 

Basic concepts of the command system:

Command: a command to execute certain operations on a computer.

Macro commands: software commands composed of several machine commands, which are software

Machine commands: between micro commands and macro commands, usually referred to as commands. Each command can complete an independent arithmetic or logical operation.

Command System: a set of commands for all machines in a computer

 

The command system is an important factor to characterize the performance of a computer. Its format and functions not only directly affect the hardware structure of the machine, but also affect the system software.

 

The command format is a structure represented by binary code. It is usually composed of an operation code field and address code field.

 

Addressing Mode:

The method to form the instruction address is called the instruction addressing method. There are two types of sequential addressing and hop addressing, which are tracked by the instruction counter.

The data addressing method is used to form the operand address. The operands can be placed in specialized registers, General registers, memory, and instructions.

Computer composition principle-Reading Notes (4) Instruction System