APS审核—计算机组成原理.docVIP

计算机组成原理 Computer Organization What computers consist of How computers work How they are organized internally What are the design tradeoffs How design affects programming and applications Turing Machine Also known as a Universal Computational Device: a theoretical device that accepts both input data and instructions as to how to operate on the data levels of abstraction Machine Architecture This is the formal specification of all the functions a particular machine can carry out, known as the Instruction Set Architecture (ISA). Microarchitecture The implementation of the ISA in a specific CPU - i.e. the way in which the specifications of the ISA are actually carried out. Logic Circuits Each functional component of the microarchitecture is built up of circuits that make “decisions” based on simple rules Devices Finally, each logic circuit is actually built of electronic devices such as CMOS or NMOS or GaAs (etc.) transistors. Logic Gates Symbols Decoder Multiplexer (MUX) Half adder Full adder The von Neumann Model Memory: holds both data and instructions Processing Unit: carries out the instructions Control Unit: sequences and interprets instructions Input: external information into the memory Output: produces results for the user Memory Each location has an address and contents Address: bit pattern that uniquely identifies a memory location Contents: bit pattern stored at a given address. analogy: p.o. boxes have fixed numbers, but changing contents Processing Unit At a minimum, has Arithmetic Logic Unit (ALU) and General Purpose Registers (GPRs). ALU Performs basic operations: add, subtract, and, not, etc. Generally operates on whole words of data. Some can also operate on subsets of words (eg. single bits or bytes). Registers: Fast “on-board” storage for a small number of words. Invaluable for intermediate data storage while processing Close to the ALU (much faster access than RAM). Control Unit The control unit coordinates all actions needed to execute th