Chapter II Summary

First, the CPU

A typical CPU consists of an operator, a controller, a register, and other devices.

Arithmetic: Information processing

Register: Information Store

Controller: Controls the operation of various devices

Second, the General register

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

AX, BX, CX, DX are called general-purpose registers

To be compatible with earlier CPU operations, these 4 registers can be split into two 8-bit registers for individual use

For example, Ax can be divided into Al and Ah registers, which are 8-bit registers that can be used independently

Three, the word storage

Bytes: One byte consists of 8 bits

Word: A word consisting of two bytes

High 8 bits of the word → high 8-bit registers stored in the Universal register

Low 8 bits of the word → low 8-bit registers stored in the general register

IV. Assembly directives

The number of bits of two manipulated objects should be consistent during data transfer and operation

Five, 8086CPU how to give a physical address

Base Address *16+ Offset address = Physical Address

VI, CS and IP

CS: Code Snippet Register

IP: Instruction Pointer register

The CPU Cs:ip the content pointed to as an instruction execution

IP is used to hold the offset address of the instruction that the CPU will read in the code snippet

Vii. jmp directives

At the same time, modify CS, IP content:

JMP segment Address: offset address

To modify only the contents of the IP:

A valid register in JMP

Chapter II Summary