1. Assembly and Machine Language

Assembly language is a programming language that works directly on top of hardware.

Machine language is a collection of machine instructions

Second, CPU

The CPU contains three instruction types: data transfer, arithmetic and logic operations, branch jumps
Data transfer: load (memory to register) and store (register to memory)
Arithmetic and logic operations: integer operations, floating point operations, binary logic operations
branch Jump: Conditional jump, unconditional jump

There are three kinds of buses between the CPU and the chip: address, control, data

The width of the address bus determines the maximum capacity of the memory space.

The width of the data bus determines the maximum speed of data transfer.

The width of the control bus determines the CPU's ability to control external devices.

Third, the register

1，8086CPU

This chapter takes 8086CPU as an example to introduce the usage of registers.

The 8086CPU has 14 registers, all of which are 16-bit.

4 general purpose registers: AX, BX, CX, DX

4 segment registers: CS, DS, ES, SS

6 non-segment registers: IP, SI, DI, SP, BP, PSW

2, general register

4 general-purpose registers: AX, BX, CX, DX can be split into 2 8-bit registers, AH, AL, BH, BL, CH, CL, DH, DL, the upper 8 bits and the lower 8 bits are calculated independently and cannot be carry.

AX is the accumulator, BX is the base register, CX is the counter, and DX is the data register.