Small Turtle series → chapter II →2.1

Source: Internet
Author: User

2nd Chapter Register (CPU operating principle)

CPU Overview

* A typical CPU is composed of an operator, a controller, a register and other devices, which are connected by the internal bus;

* Difference: The internal bus realizes the connection between each device inside the CPU, and the external bus realizes the connection between the CPU and other devices on the motherboard;

*8086CPU has 14 registers {AX,BX,CX,DX,SI,DI,SP,BP,IP,CS,SS,DS,ES,PSW}

2.1 General-Purpose registers

*8086CPU all registers are 16-bit and can hold two bytes;

*AX,BX,CX,DX is typically used to store general data, known as general-purpose registers

*ax, for example, looks at the logical mechanism of the Register ↓

* A 16-bit register can store a 16-bit data. ↓

→ Data: 18; binary representation: 10010;

→ Store in register ax: ↓

* What is the maximum amount of data that a 16-bit register can store?

→2 16-time minus 1

The registers in the CPU of the previous generation of *8086 are all 8 bits;

* To ensure compatibility, these four registers can be divided into two separate 8-bit registers to use; ↓

→*ax can be divided into Ah and al;

→*BX can be divided into BH and BL;

→*CX can be divided into ch and cl;

→*DX can be divided into DH and DL; (H: High; L: low;)

*8086CPU 8-bit register storage logic ↓

→ In the case of AX, 8086CPU 16-bit registers are divided into two 8-bit registers ↓

The Low 8 bits (0-7) of the *ax form the Al register, and the high 8 bits (8-15) Form the AH register.

*ah and Al registers are 8-bit registers that can be used independently; (Downward ↓ compatible)

*8086CPU 8-bit memory data storage ↓

* What is the maximum amount of data that a 8-bit register can store?

→2 8-time minus 1






Small Turtle series → chapter II →2.1

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.