Computer architecture

Computer architecture is the conceptual design and fundamental operational structure of a computer system. That is, it is a model and functional description of the requirements and design implementations for various parts of a computer, with special interest in the way the central processing unit (CPU) works internally and accesses memory addresses.

The architecture of the computer is also based on three main principles that apply to every device or component of the computer, these three principles are: speed, capacity and type of connection.

It is also usually defined as the way of interconnecting hardware components, to create computers according to the requirements of functionality, performance and cost.

The computer receives and sends the information through the peripherals, through the channels. The CPU is in charge of processing the information that reaches the computer. The exchange of information has to be done with the peripherals and the CPU. It can be considered that all those units of a system, except for the CPU, are called peripherals, so the computer has two well-defined parts, which are:

1. The CPU (in charge of running programs and which is also considered composed of the main memory, the arithmetic logical unit and the control unit).
2. The peripherals (which can be input, output, entry/output, storage and communications).

Introduction

The implantation of instructions is similar to using an assembly string in a manufacturing factory. In assembly lines, the product goes through many stages of production before having the product assembled. Each stage or segment of the chain is specialized in a specific area of the production line and always carries out the same activity. This technology is applied in the design of efficient processors.

These processors are known as pipeline processors. These are composed of a list of linear and sequential segments where each segment carries out a task or a group of computational tasks. The data that comes from abroad is entered into the system to be processed. The computer performs operations with the data it has stored in memory, produces new data or information for external use.

Architectures and instruction sets can be classified considering the following aspects:

• Storage of operations in the CPU: where operators are located apart from the information subtractor (SI).
• Number of explicit operations by instruction: How many operating are expressed explicitly in a typical instruction. It's usually 0, 1, 2 and 3.
• Operating position: Any operating may be in memory, or should some or all be in the internal records of the CPU?. How the memory address is specified (addressing modes available).
• Operations: what operations are available in the set of instructions.
• Type and size of operations and how they are specified.

Logic Gates

They are in charge of processing the logic of the system instructions. There are seven different basic types:

• NOT: it is the denial of the entry. It works with one input and one output.
• AND: is the binary multiplication of two entries and gives a single output.
• OR: is the binary sum of two inputs and gives as output the own sum or the bit carry if necessary.
• XOR: is the binary sum of two inputs and gives the result as output, without including the carry bit.
• NAND: It's AND's denial. It gives a single exit.
• NOR: is the denial of OR. It gives a single exit.
• XNOR: is the denial of XOR. It gives a single exit.

Storing operands in the CPU

The basic difference is in the internal storage of the CPU. The main alternatives are:

• Accumulating.
• Records set.
• Memory.

But first, we must take into account that the information processed is extremely important.

Features

• In an architecture of accruing, an operating is implicitly in the accumulator always reading and entering data (e.g. a standard calculator).
• In the architecture of a battery It is not necessary to name the operators as they are in the top of the stack (e.g., HP battery calculator).
• The architecture of records has only explicit operations (it is the one that is named) in records or memory.

Advantages of architectures

• Pila:
  • Simple model for expression evaluation (inverse Polish presentation).
  • Short instructions can give good code density.
• Accumulator:
  • Short instructions.
  • Minimizes internal machine states (simply control unit).
• Registration:
  • More general model for similar instruction code.
  • Automates code generation and reuse of operations.
  • Reduce traffic to memory.
  • A computer has 32 records, as standard.
  • Access to data is faster and faster.

Disadvantages of architectures

• Pila:
  • A battery cannot be accessed randomly.
  • This limitation makes it difficult to generate efficient code.
  • It also makes it difficult to implement efficiently, as the stack becomes a bottleneck, that is, there is difficulty in transferring data at its mk speed.
• Accumulator:
  • As the accumulator is only temporary storage, memory traffic is the highest in this approach.
• Registration:
  • All operators must be appointed, leading to longer instructions.