Compilation (1) _ Basic knowledge

• CPU-to-memory read/write

If your program is going to operate on some memory, then you need to know a few messages:

1. memory address;

2. The operation needs to be performed (this is assumed to be read);

3. Size of the operation

So what if the CPU is helping you perform these operations?

1.CPU transfer memory address to memory via address bus

2.CPU transmit read command and size to memory via control bus

3. Memory returns the requested data to the CPU via a data bus

• Class 3 Bus Description

The above Class 3 bus, address/control/Data bus refers to the CPU and other chips (memory) connected to the wire, which according to different functions of the division.

first, look . Address bus

As we can see from the above, address bus is primarily used to specify memory locations. So the number of address lines is related to the current computer's addressing,

Typically, the 32-bit/64-bit representation we describe is address bus.

the addressable range for the 32-bit system is therefore: 0~2^32=2^2 * 2^30 = 0~4 GB, 64 bits: 0~2^64

Graphically represents a 8-bit system addressing 11 o'clock condition:

　　

Then look at the data bus

As you can see, the data bus is used to transmit data, so how many numbers of buses determine the amount of data to be transmitted at one time.

The corresponding calculation method is the same as address bus.

For example, a 16-bit system transmits 89D8:

　　

Finally, the control bus

The control bus is used to control the number of operation types.

• Peripheral IO Description

　　Physical connection:

The general peripherals are physically connected using slots, in essence the CPU can control peripherals through cup<-> slots <-> peripherals.

　　Memory Connections:

The system unifies the memory of the connected peripherals to form a list.

The CPU transmits the corresponding memory address by means of address bus, control the relative peripherals.

The rest of the operation is the same as the CPU controls the machine.

• Reference

<< assembly language >> Wang Shuang

Compilation (1) _ Basic knowledge