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ChrisLi-Tech

CS笔记 23.04.12

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Table of Contents

Unit4: CPU Architecture

Interrupts 中断信号：

  • signal to stop CPU to figure out what to do next

  • allow computer to multitasking 多任务 （不断的切换任务，模拟同时 ）

紧急任务需要处理 interrupt signal ， 如何判断紧急的程度 priority of interrupt

at the end of F-E cycle, checking if there is an interrupt signal .

  • checking the priority of process , if high enough

  • saving the register and process states into stack .

  • loading the address of ISR （interrupt service routine） into PC,

  • once the ISR is completed, resume the interrupted process and run it continually

RTN register transfer notation

MAR <--- [PC]  //the content of PC  is copied into MAR  by  address bus
MDR <---- [[MAR]] //the content of conent  MAR   is copied into MDR
CIR <---- [MDR] //the content of MDR  is copied into  CIR
PC <-- [PC] + 1 //the content of PC  increments

ACC accumulator 累加器

  • contained in ALU

  • to store result during calculation temporarily

IX index register

  • using indexed addressing

  • e.g. finding the address of a [2 ]

SR state register

  • showing the state of result after calcualtion

  • contain 4 flags : zero , negative, overflow, carry out

Von Neumann architecture (stored program concept)

  • CPU , memory , I/O device

  • instruction and data are stored into memory

  • the instruction can be feteched and executed

  • one after another automatically

ALU:

  • arithmetic logic unit, do arithmetic operations,

  • Do logic operations

  • contain ACC register

CU:

  • Control Unit

  • decoding the instruction and sending control signal

IAS

  • immediate access store

  • a piece of memory in CPU to store

  • data and instruction to be executed temporarily

  • Main memory in CPU (Cache)

Bus

  • address bus : transfer address unidirectional

  • data bus : transfer data bidirectional

  • control bus : transfer control signal bidirectional

control signal 控制信号

  • read / write signal to memory

  • system clock 系统时钟

system clock

  • it is an electrical pulse signal to synchronize all the compements

  • in computer system and allow them work together

  • unit : Hz

two-pass assembler

one pass

  • reading one line of code at a time

  • allocate the memory for a line of code

  • ignoring unnecessary character like extra space , comments

  • checking if the opcode is valid according to instruction set

  • create / establish symbol table

two-pass

  • reading the souce code line by line

  • translate the souce code into object code / executable file

  • saving or running the object code