Introduction to Computer Engineering CS/ECE 252, Fall 2016 Kai Zhao Computer Sciences Department University of Wisconsin – Madison

Pop Quiz, Material from Lecture 1 There are _ homeworks with _ dropped. Homeworks are worth __% of the total grade. There are _ exams with _ dropped. Exams are worth __% of the total grade. Define Moore’s Law Which of the following topic(s) does this course cover? Application programs Machine language Digital design Operating systems Computer architecture Electronic circuits Compilers

In-class Exercise; Lecture 1 Review There are _ homeworks with _ dropped. Homeworks are worth __% of the total grade. There are _ exams with _ dropped. Exams are worth __% of the total grade. Define Moore’s Law Which of the following topic(s) does this course cover? Application programs Machine language Digital design Operating systems Computer architecture Electronic circuits Compilers

Chapter 1 Welcome Aboard Slides based on set prepared by Gregory T. Byrd, North Carolina State University

Computer System: Layers of Abstraction Application Program Language Instruction Set Architecture (and I/O Interfaces) Microarchitecture Circuits Devices Algorithms Software Hardware Good to know both

Big Idea #1: Universal Computing Device All computers, given enough time and memory, are capable of computing exactly the same things. = = Eventually, they’re going to stop calling smartphones, smartphones. People will refer to them as phone. Phone Workstation Supercomputer

Turing Machine A device with 3 parts Tape of slots Read/write head State machine to decide what to write and where a tape consisting of slots in which numbers may be written a read/write head that can move along the tape reading the numbers written there or writing numbers onto the tape (or possibly overwriting numbers already written on the tape) a state machine by which it will decide what numbers to write and where on the tape to write them.

Tadd Tmul Turing Machine Mathematical model of a device that can perform any computation – Alan Turing (1937) ability to read/write symbols on an infinite “tape” state transitions, based on current state and symbol Every computation can be performed by some Turing machine. (Turing’s thesis) Tadd a,b a+b Turing machine that adds Tmul a,b ab Turing machine that multiplies Turing predated computers; worked at Bletchley Park during WW2 More interested in the theory of computing: what was possible Turing award is given to the individual for best technical contributions to the computer science community. Since 2014, it is accompanied with $1 million prize pool.

Universal Turing Machine Turing’s thesis: Turing described a Turing machine that could implement all other Turing machines. inputs: data, plus a description of computation (Turing machine) U a,b,c c(a+b) Universal Turing Machine Tadd, Tmul U is programmable – so is a computer! instructions are part of the input data a computer can emulate a Universal Turing Machine, and vice versa Therefore, a computer is a universal computing device!

From Theory to Practice In theory, computer can compute anything that’s possible to compute given enough memory and time In practice, solving problems involves computing under constraints. time weather forecast, next frame of animation, ... cost cell phone, automotive engine controller, ... power cell phone, handheld video game, ... Cryptography

Abstraction An interface is a description of the inputs and the expected outputs. When you order food online, you only need to know what you want, your address, and payment information. Then in about 30 minutes, they should deliver your order to you.

Abstraction An implementation is the actual mechanism that causes the user’s input to turned into corresponding outputs. When you order food online, you only need to know what you want, your address, and payment information. Then in about 30 minutes, they should deliver your order to you.

Big Idea #2: Transformations Between Layers How do we solve a problem using a computer? A systematic sequence of transformations between layers of abstraction. Problem Software Design: choose algorithms and data structures Algorithm Programming: use language to express design Problem Statement stated using "natural language" may be ambiguous, imprecise Algorithm step-by-step procedure, guaranteed to finish definiteness, effective computability, finiteness Program express the algorithm using a computer language, no ambiguity high-level language, low-level language Instruction Set Architecture (ISA) specifies the set of instructions the computer can perform data types, addressing mode Program Compiling/Interpreting: convert language to machine instructions Instr Set Architecture

Descriptions of Each Level Problem Statement stated using "natural language" may be ambiguous, imprecise E.g. “Time flies like an arrow” Algorithm step-by-step procedure, guaranteed to finish definiteness, effective computability, finiteness Program express the algorithm using a computer language, no ambiguity high-level language, low-level language Instruction Set Architecture (ISA) specifies the set of instructions the computer can perform data types, addressing mode Time flies like an arrow could have 3 meanings One is noticing how fast time passes by pretty fast. One is at a track meet for insects. One is saying time flies (as opposed to fruitflies or dragonflies) are in love with an arrow. Definiteness describe the notion that each step is precisely stated. E.g. not “stir until lumpy” since lumpiness is not precise. Effective computability describe the notion that each step can be carried out by a computer. E.g. not “compute the largest prime number” since it doesn’t exist. Finiteness describe the notion that the procedure terminates. E.g. not some shampoo bottles that says, “rinse and repeat”. Programs can’t have ambiguity.

Deeper and Deeper… Processor Design: Instr Set Architecture Processor Design: choose structures to implement ISA Microarch Logic/Circuit Design: gates and low-level circuits to implement components Circuits Microarchitecture detailed organization of a processor implementation different implementations of a single ISA Logic Circuits combine basic operations to realize microarchitecture many different ways to implement a single function (e.g., addition) Devices properties of materials, manufacturability Process Engineering & Fabrication: develop and manufacture lowest-level components Devices

Descriptions of Each Level (cont.) Microarchitecture detailed organization of a processor implementation different implementations of a single ISA Logic Circuits combine basic operations to realize microarchitecture many different ways to implement a single function (e.g., addition) Devices properties of materials, manufacturability

Many Choices at Each Level Solve a system of equations Gaussian elimination Jacobi iteration Red-black SOR Multigrid FORTRAN C C++ Java Intel x86 Sun SPARC Compaq Alpha Pentium II Pentium III AMD Athlon Ripple-carry adder Carry-lookahead adder CMOS Bipolar GaAs Tradeoffs: cost performance power (etc.) SOR = successive over-relaxation Methods to solve linear systems Sun and Java are trademarks of Sun Microsystems, Inc. SPARC is a trademark of SPARC International, Inc. Intel and Pentium are trademarks of Intel Corporation. Compaq and Alpha are trademarks or service marks of Compaq Computer Corporation. AMD and Athlon and trademarks of Advanced Micro Devices, Inc.

Adders Carry Look ahead Adder (CLA) Ripple Carry Adder http://i.imgur.com/YyXnqRv.gifv Sun and Java are trademarks of Sun Microsystems, Inc. SPARC is a trademark of SPARC International, Inc. Intel and Pentium are trademarks of Intel Corporation. Compaq and Alpha are trademarks or service marks of Compaq Computer Corporation. AMD and Athlon and trademarks of Advanced Micro Devices, Inc. Carry Look Ahead Adder 3 4 5 6 7 + 1 2 3 4 5 4__9____

What’s Next Bits and Bytes Digital Logic Processor and Instruction Set How do we represent information using electrical signals? Digital Logic How do we build circuits to process information? Processor and Instruction Set How do we build a processor out of logic elements? What operations (instructions) will we implement? Assembly Language Programming How do we use processor instructions to implement algorithms? How do we write modular, reusable code? (subroutines) I/O, Traps, and Interrupts How does processor communicate with outside world? Bits and Bytes – chapter 2 Digital Logic – chapter 3 Processor and Instruction Set – chapter 4-5 Assembly Language Programming – chapters 6-7 I/O, Traps, and Interrupts – chapters 8-9 We hope you enjoy the ride.