Basic knowledge of compiling learning records

---

One 、 Basic knowledge of

1. The composition of assembly language

1. Assembly instruction （ Mnemonics for machine codes ）
2. Pseudo instruction （ By compiler ）
3. Other symbols （ Recognized by compiler , Such as ：+ - * /）
 The core of assembly language is assembly instruction , He determined the characteristics of assembly language 

2. Memory

 Used to store data and instructions ( Equivalent to what we call memory )

3. Instructions and data

 In terms of memory or disk , Data and instructions are binary information ,cpu Distinguish between them at work .

4. Storage unit

1. Each storage unit is from 0 Numbered starting ( Analogical array ).
2.1Byte( byte )=8bit( Binary system ),  A storage unit is 1byte.
3. A memory has 128 Storage unit , Can be stored 128Byte
4.1kb = 1024b 1mb=1024kb 1gb=1024mb 1tb=1024gb 

5.cpu Read and write to memory

  Satisfy 3 Conditions ( Find a place   What do you do   What to do )
 	1.  Address of the storage unit ( Address information )
 	2.  Device selection , A command to read or write ( Control information )
 	3.  Read or write data ( Data and information )

6. Bus

From a physical point of view, it is a collection of wires , From a logical point of view, it can be divided into the following three types :
1. Address bus ( Addressing capability )

  1. The memory unit is specified by the address bus , The number of different messages that the address bus can transmit , To determine the 
cpu How many storage units can be addressed 
  2. One cpu Yes N Root address bus , Then cpu The width of the address bus is N, At most, you can look for 2 Of 
N Next memory unit ( A thread 0 1 Two kinds of state )	(8kb The address bus width of is 13(2^13b))

2. data bus ( Data transmission volume )

  1. The width of the data bus determines cpu And the speed of external data transmission .
  2.8 The root data bus can transmit one at a time 8 Bit binary data ( A byte )	

3. Control bus ( The ability to control external devices )

  1. How many control buses , It means how many kinds of control to external devices . 

7. Memory address space

cpu The address width is N,  Memory units have 2 Of N Power , All memory cells make up the memory address space 

8. a main board

 There are core devices and main devices on the motherboard ,  There is a bus connection  

9. Interface card

 Peripheral ( Keyboard mouse, etc ) It consists of expansion slots ( Interface card ) Via bus and cpu Connected to a , So as to be controlled 

10. Memory chips

1. Ram :  Deposit cpu Most of the programs and data used 
2. Equipped with BIOS( Basic I / O system ) Of ROM:  Perform the most basic input and output 
3. On the interface RAM:  Used for input on the interface card \ Temporary storage of output data 

11. Memory address space

cpu When the above devices are operated through the bus ,  Think of them as a total logical memory ( Memory ), namely 
 Memory address space 

Exercises and answers

（1）1 individual CPU The addressing capability of is 8KB, So the width of its address bus is 13 position .

	 analysis : 8KB=2^13B  

（2）1KB Your memory has 1024 Storage unit , The number of the storage unit is from 0 To 1023 .

	1 The storage unit corresponds to 1Byte

（3）1KB Your memory can store 8192（2^13） individual bit, 1024 individual Byte.

（4）1GB yes 1073741824 （2^30） individual Byte、1MB yes 1048576 (2^20) individual Byte、1KB yes **1024（2^10)** individual Byte.

（5）8080、8088、80296、80386 The address bus widths of are 16 root 、20 root 、24 root 、32 root , Then their addressing capabilities are : 64 （KB）、 1 （MB）、 16 （MB）、 4 （GB）.

 Address bus width is n === 2^nB  Unit replacement 

（6）8080、8088、8086、80286、80386 The data bus widths of are 8 root 、8 root 、16 root 、16 root 、32 root . Then the data they can transmit at one time is : 1 （B）、 1 （B）、 2 （B）、 2 （B）、 4 （B）.

N The root address bus can be worn at one time N Binary data (byte),8byte = 1B

（7） Read from memory 1024 Bytes of data ,8086 At least read it 512 Time ,80386 At least read it 256 Time .

（8） In memory , Data and procedures to Binary system Form storage .