Assembly Language # The first chapter of basic knowledge

I. Machine language

1. Definition: a collection of machine instructions. (The machine instruction is a string of binary digits.) )
2. working process : The computer makes the machine instruction into high and low frequency, drives the electronic device, carries on the computation.

Two. Assembly language

• composition : (1). Assembly instruction (CORE): The mnemonic of the machine code, with the corresponding machine code.

(2). Pseudo-directive: there is no corresponding machine code, executed by the compiler, the computer does not execute.

(3) Other symbols: Recognized by the compiler, there is no corresponding machine code.

• working Process : Assembly Instructions--compiler--machine code--Computer

Three. CPU

• Memory : (1) Definition: In bytes is divided into several storage units, the capacity is measured in KB,GB,MB.
• instructions and Data : (1) There is no difference between the instruction and the data on the memory or on the disk.
• the CPU reads and writes to the Memory : (1) cpu--address Bus--Specifies the memory unit; {Address bus: A CPU has n address bus, Width N, can find 2N storage units}

(2) cpu--via data bus-with memory and other components   (1) The width of the data bus determines the transmission speed. 2.8 Data Bus can pass a 8-bit binary at a time--a B)

(3) cpu--through the control bus-external device for reading and writing (bus width determines the ability of external control)

• Memory address Space : (1) Definition: Set a CPU address bus width is n, then can be addressed to 2n memory units, this 2n can be found in the memory unit is the memory address space of the CPU. (Addressing space)
• motherboard : Logically divided into address bus, logic bus, control bus
• Interface card
• various types of memory chips (1) classification according to read and write attributes
  ① Random Memory Ram
  ② read-only memory rom
  (2) Classification according to function and connection
  ① primary random memory Ram
  ② BIOS-equipped ROM
  ③ RAM on the interface card

(4) comparison of three languages :

	machine language	assembly language	advanced language
Can the computer directly identify	can	cannot	cannot
Ease of use	poor		good
occupy space	small	small	big
Execution speed	Fast	Fast	Slow
Use	Special Encryption / decryption	System core requirements Fast, Code short program Direct manipulation of I/O information security	General Software Development

Assembly Language # The first chapter of basic knowledge