Page 1. Last Time. Today. Embedded Compilers. Compiler Requirements. What We Get. What We Want
|
|
- Howard Benson
- 5 years ago
- Views:
Transcription
1 Last Time Today Low-level parts of the toolchain for embedded systems Linkers Programmers Booting an embedded CPU Debuggers JTAG Any weak link in the toolchain will hinder development Compilers: Expectations and reality C for embedded systems Lots of things make C for embedded systems different from C for Windows or Linux Raw device access Inline assembly Interrupts Etc. Not enough to just be good at C Also: This all applies to C++ But we re not going to talk about C++ explicitly Embedded Compilers Compiler Requirements Today: General capabilities Specific issues part 1 First: Almost all compilers for embedded systems are cross-compilers Compiler runs on an architecture other than its target Does this matter at all? Be correct Embedded compilers are notoriously buggy Relatively few copies sold Diverse hardware impedes thorough testing Produce small, fast code Speed and size are conflicting goals Oops! Take advantage of platform-specific features Produce code that s easy to debug Conflicts with optimization Whole-program optimization particularly problematic What We Want You want to tell the compiler: There are only 32 KB of RAM Program must fit, but there s no point reducing RAM consumption further There are only 256 KB of ROM Again: Program must fit but there s no point reducing ROM consumption further Interrupt handler 7 is time critical So make it very fast, even if this bloats code Threads 8-13 are background threads Performance is unimportant so focus on reducing code size What We Get A few compiler flags: -O2, -Os, Etc. May or may not do what you want Typically no flags for controlling RAM usage Grim realities: Meeting resource constraints is 100% your problem Shouldn t assume compiler did the right thing Shouldn t assume code you reuse does the right thing Including the C library Figure out which resources matter and focus on dealing with them Changing or upgrading compiler mid-project is usually very bad Page 1
2 Nice Example Why use C? From a 1982 book on 6502 assembly programming: strcmp(): compare two strings Registers used: all Execution time: * length of shorter string Code size: 52 bytes Data size: 4 bytes on page 0 4 bytes to hold the string pointers Try to find this information for current C libraries! Mid-level language Some high-level features Plenty of low-level control Type system easily subverted C is popular and well-understood Plenty of good developers exist Plenty of good compilers exist Plenty of good books and web pages exist There s no obviously superior choice Why not use C? Hard to write portable code For example int does not have a fixed size Hard to write correct code Very hard to tell when your code does something bad E.g. out-of-bounds array reference This is Microsoft s major problem Language standard is weak in some areas Means there is plenty of diversity in implementations Linking model is unsafe Preprocessor is poorly designed CPP the C Preprocessor CPP runs as a separate pass before the compiler Basic usage: #define FOO 32 int y = FOO; Compiler sees: int y = 32; CPP operates by lexical substitution Important: The compiler never sees FOO So of course the debugger, linker, etc. do not know about it either Some Interesting Macros Macro Problems #define PLUS_ONE(x) x+1 int a = PLUS_ONE(y)*3 #define TIMES_TWO(x) (x*2) int a = TIMES_TWO(1+1) #define MAX(x,y) ((x)>(y)?(x):(y)) void f () { int m = MAX(a++,b); #define INT_POINTER int * INT_POINTER x, y; Root of the problem: C preprocessor is highly error-prone Avoid it except to do very simple things Fully parenthesize macro definitions Make macro usage conventions clear Entertaining macros: #define DISABLE_INTS asm volatile ( cli ); { #define ENABLE_INTS asm volatile ( sei ); Is this good or bad macro usage? Page 2
3 Macro Avoidance Old conventional wisdom: Careful use of CPP is good New conventional wisdom: Most uses of CPP can be avoided Trust the optimizer Constants Use #define X 10 const int X = 10; Functions Use #define INC_X x++ inline void INC_X(void) { x++ More Macro Avoidance Conditional compilation #if FOO #endif Use if (FOO) { #ifdef X86 #endif Put x86 code into a separate file However: Design of C makes it impossible to avoid macros entirely C++ much better in this respect Bit Manipulation without Macros Something like this is good: void set_bit (int *a, int bit) { (*a) = (1<<bit); void clear_bit (int *a, int bit) { (*a) &= ~(1<<bit); CPP in Action Sometimes you need to look at the CPP output That is, see what the C compiler really sees There s always a way to do this In CodeWarrior, do this using the IDE For gcc: gcc E foo.c Accessing Device Registers Many embedded chips map device registers into RAM This is memory mapped I/O These registers do not act like RAM Each read may return a different value Writes may be ignored Reads and writes can be side effecting Page 3
4 Accessing Device Registers What happens if we access a register like this: extern int CTRL_REG; set_bit (&CTRL_REG, 3); Compiler may add, delete, and reorder references to this register Compiler thinks the register is in RAM Optimizing CPUs can do similar things What if bit 4 of CTRL_REG is the one that lowers the control rod into the reactor? And the compiler eliminates the write Oops! Solution: Volatile Qualifier In C you can mark any variable as volatile Compiler is no longer permitted to assume that Retains its value after a read or write Reads from and writes to the variable have no side effects Easy implementation strategy for compiler writers: Refuse to optimize any function that accesses any volatile variable Some compilers actually do this Volatile is a storage qualifier, like const Volatile Example C code you might write: /* Enable signal as GPIO */ void make_pin0_gpio (void) { MCF_GPIO_PTCPAR = MCF_GPIO_PTCPAR_DTIN0_GPIO; Relevant reprocessor definitions: typedef volatile uint8 vuint8; #define MCF_GPIO_PTCPAR \ (*(vuint8 *)(& IPSBAR[0x10006F])) #define MCF_GPIO_PTCPAR_DTIN0_GPIO (0) Volatile Example After the C processor has run, the code is: void make_pin0_gpio (void) { (*(vuint8 *)(& IPSBAR[0x10006F])) = (0); So, this is the code the CodeWarrior compiler actually sees and compiles Note: vuint8 * is pointer-to-volatile, not volatile-pointer The distinction is crucial Hardware register access is typically done using pointers-to-volatile Compiler Output Different Example _make_pin0_gpio: 0x link a6, #0 0x moveq #0, d0 0x move.b d0, IPSBAR x C unlk a6 0x E rts C code you might write: /* Enable signal as GPIO */ void make_pin0_gpio (void) { MCF_GPIO_PTCPAR = MCF_GPIO_PTCPAR_DTIN0_GPIO; Expands out to: void make_pin0_gpio_bogus (void) { (*(vuint8 *)(& IPSBAR[0x10006F])) = (0) ; Page 4
5 Compiler Output _make_pin0_gpio_bogus: 0x link a6, #0 0x move.b IPSBAR , d0 0x A unlk a6 0x C rts 0x E nop So What Does Volatile Really Mean? Does not mean suppress optimizations It means: loads from and stores to a volatile location must not be added or deleted, and must occur in program order What happened? Is the code what we wanted? Is the compiler correct? What does volatile NOT mean? Accesses to volatiles are not necessarily atomic Accesses to volatiles may be moved past accesses to non-volatiles Example: volatile int flag; void interrupt (void) { flag = 1; void not_interrupt (void) { while (flag == 0); do stuff Volatile Problem Compiler can transform your code to this: void not_interrupt (void) { do stuff while (flag == 0); Better: void not_interrupt (void) { while (flag == 0); BARRIER; do stuff Memory Barriers In gcc a compiler barrier looks like this: asm volatile ( : : : memory ); Says to the compiler: No code motion around this statement This statement may affect any RAM location, so: Store all register values to RAM before the barrier Reload values from RAM into register after the barrier How to do this is CodeWarrior??? Nothing in the docs Best guess: CodeWarrior does not do reordering optimizations More Barrier Issues Compiler isn t the only source of problems! Smart memory subsystems can reorder operations Apparently redundant operations can be suppressed Important: Device memory must be marked as non-caching Locks must include not only compiler barriers but also processor-specific memory system barriers Page 5
6 Volatile Summary Does this make sense? const volatile int x; Use volatiles to protect access to hardware registers Do not build your own locks A lock is anything that you use to enforce sequencing or mutual exclusion between concurrent computations Even experts get these wrong Summary C compilers make writing embedded software feel a lot like writing regular software However: Lots of subtle differences between writing Windows / Linux code and embedded code Need to understand these and cope with them Easy to get burned and create very difficult debugging problems Page 6
Last Time. Low-level parts of the toolchain for embedded systems. Any weak link in the toolchain will hinder development
Last Time Low-level parts of the toolchain for embedded systems Ø Linkers Ø Programmers Ø Booting an embedded CPU Ø Debuggers Ø JTAG Any weak link in the toolchain will hinder development Today: Intro
More informationPage 1. Lab. Something Cool. Quiz Results. Last Time. Embedded Compilers. Today: Intro to Embedded C
Something Cool Lab RFID is an exciting and growing technology This reader from Parallax is $40 and has a serial interface Lab 1 due next Tues Seemed to go pretty well on Tues? Questions? Quiz Results Last
More informationSomething Cool. RFID is an exciting and growing. This reader from Parallax is $40 and has a serial interface
Something Cool RFID is an exciting and growing technology This reader from Parallax is $40 and has a serial interface Lab Lab 1 due next Tues Seemed to go pretty well on Tues? Questions? Quiz Results Problem
More informationLast Time. Compiler requirements C preprocessor Volatile
Last Time Compiler requirements C preprocessor Volatile Today Coding and translation of interrupt handlers Coding inline assembly Compiler intrinsics Interrupts 30-second interrupt review: Interrupts are
More informationAdvanced use of the C language
Advanced use of the C language Content Why to use C language Differences from Java Object oriented programming in C Usage of C preprocessor Coding standards Compiler optimizations C99 and C11 Standards
More informationDevice I/O Programming
Overview Device I/O Programming Don Porter CSE 506 Many artifacts of hardware evolution Configurability isn t free Bake-in some reasonable assumptions Initially reasonable assumptions get stale Find ways
More informationPage 1. Stuff. Last Time. Today. Safety-Critical Systems MISRA-C. Terminology. Interrupts Inline assembly Intrinsics
Stuff Last Time Homework due next week Lab due two weeks from today Questions? Interrupts Inline assembly Intrinsics Today Safety-Critical Systems MISRA-C Subset of C language for critical systems System
More informationECEN 449 Microprocessor System Design. Hardware-Software Communication. Texas A&M University
ECEN 449 Microprocessor System Design Hardware-Software Communication 1 Objectives of this Lecture Unit Learn basics of Hardware-Software communication Memory Mapped I/O Polling/Interrupts 2 Motivation
More information(Embedded) Systems Programming Overview
System Programming Issues EE 357 Unit 10a (Embedded) Systems Programming Overview Embedded systems programming g have different design requirements than general purpose computers like PC s I/O Electro-mechanical
More informationSoftware Engineering /48
Software Engineering 1 /48 Topics 1. The Compilation Process and You 2. Polymorphism and Composition 3. Small Functions 4. Comments 2 /48 The Compilation Process and You 3 / 48 1. Intro - How do you turn
More informationA software view. Computer Systems. The Compilation system. How it works. 1. Preprocesser. 1. Preprocessor (cpp)
A software view User Interface Computer Systems MTSU CSCI 3240 Spring 2016 Dr. Hyrum D. Carroll Materials from CMU and Dr. Butler How it works hello.c #include int main() { printf( hello, world\n
More informationC Review. MaxMSP Developers Workshop Summer 2009 CNMAT
C Review MaxMSP Developers Workshop Summer 2009 CNMAT C Syntax Program control (loops, branches): Function calls Math: +, -, *, /, ++, -- Variables, types, structures, assignment Pointers and memory (***
More informationIntroduction to C CMSC 104 Spring 2014, Section 02, Lecture 6 Jason Tang
Introduction to C CMSC 104 Spring 2014, Section 02, Lecture 6 Jason Tang Topics History of Programming Languages Compilation Process Anatomy of C CMSC 104 Coding Standards Machine Code In the beginning,
More informationME 4447/6405 Introduction to Mechatronics Instructor: Professor Charles Ume
ME 4447/6405 Introduction to Mechatronics Instructor: Professor Charles Ume Lecture on Codewarrior Integrated Development Environment Contents Overview of C Compliers for HCS12 CodeWarrior Pointers Interrupts
More informationMemory Consistency Models
Memory Consistency Models Contents of Lecture 3 The need for memory consistency models The uniprocessor model Sequential consistency Relaxed memory models Weak ordering Release consistency Jonas Skeppstedt
More informationNewbie s Guide to AVR Interrupts
Newbie s Guide to AVR Interrupts Dean Camera March 15, 2015 ********** Text Dean Camera, 2013. All rights reserved. This document may be freely distributed without payment to the author, provided that
More informationEL6483: Brief Overview of C Programming Language
EL6483: Brief Overview of C Programming Language EL6483 Spring 2016 EL6483 EL6483: Brief Overview of C Programming Language Spring 2016 1 / 30 Preprocessor macros, Syntax for comments Macro definitions
More informationSynchronization. CS61, Lecture 18. Prof. Stephen Chong November 3, 2011
Synchronization CS61, Lecture 18 Prof. Stephen Chong November 3, 2011 Announcements Assignment 5 Tell us your group by Sunday Nov 6 Due Thursday Nov 17 Talks of interest in next two days Towards Predictable,
More informationLab Assignment Each team will independently implement the launch interceptor specification For this assignment, you re writing portable C code
Lab Assignment Each team will independently implement the launch interceptor specification For this assignment, you re writing portable C code We ll worry about I/O later Lab Assignment You are allowed
More informationThe C Preprocessor (and more)!
The C Preprocessor (and more)! Peter Kristensen 2012-11-19 Peter Kristensen The C Preprocessor (and more)! Outline 1 C Pre Processor Compiler Assembler Linker Frontend 2 Simple directives Headers Macros
More information[537] Locks. Tyler Harter
[537] Locks Tyler Harter Review: Threads+Locks CPU 1 CPU 2 running thread 1 running thread 2 RAM PageDir A PageDir B CPU 1 CPU 2 running thread 1 running thread 2 RAM PageDir A PageDir B Virt Mem (PageDir
More informationx86 architecture et similia
x86 architecture et similia 1 FREELY INSPIRED FROM CLASS 6.828, MIT A full PC has: PC architecture 2 an x86 CPU with registers, execution unit, and memory management CPU chip pins include address and data
More informationCOMP 7860 Embedded Real- Time Systems: Threads
COMP 7860 Embedded Real- Time Systems: Threads Jacky Baltes Autonomous Agents Lab University of Manitoba Winnipeg, Canada R3T 2N2 Email: jacky@cs.umanitoba.ca WWW: http://www.cs.umanitoba.ca/~jacky http://aalab.cs.umanitoba.ca
More informationCS16 Week 2 Part 2. Kyle Dewey. Thursday, July 5, 12
CS16 Week 2 Part 2 Kyle Dewey Overview Type coercion and casting More on assignment Pre/post increment/decrement scanf Constants Math library Errors Type Coercion / Casting Last time... Data is internally
More informationME 4447/ME Microprocessor Control of Manufacturing Systems/ Introduction to Mechatronics. Instructor: Professor Charles Ume
ME 4447/ME 6405 Microprocessor Control of Manufacturing Systems/ Introduction to Mechatronics Instructor: Professor Charles Ume Lecture on Codewarrior Integrated Development Environment Contents Overview
More informationSlide Set 5. for ENCM 339 Fall Steve Norman, PhD, PEng. Electrical & Computer Engineering Schulich School of Engineering University of Calgary
Slide Set 5 for ENCM 339 Fall 2016 Steve Norman, PhD, PEng Electrical & Computer Engineering Schulich School of Engineering University of Calgary October 2016 ENCM 339 Fall 2016 Slide Set 5 slide 2/32
More informationImportant From Last Time
Important From Last Time Embedded C Pros and cons Macros and how to avoid them Intrinsics Interrupt syntax Inline assembly Today Advanced C What C programs mean How to create C programs that mean nothing
More informationPage 1. Today. Important From Last Time. Is the assembly code right? Is the assembly code right? Which compiler is right?
Important From Last Time Today Embedded C Pros and cons Macros and how to avoid them Intrinsics Interrupt syntax Inline assembly Advanced C What C programs mean How to create C programs that mean nothing
More informationEmbedded Systems Programming - PA8001
Embedded Systems Programming - PA8001 http://goo.gl/ydeczu Lecture 2 Mohammad Mousavi m.r.mousavi@hh.se Center for Research on Embedded Systems School of Information Science, Computer and Electrical Engineering
More informationC Language Programming
Experiment 2 C Language Programming During the infancy years of microprocessor based systems, programs were developed using assemblers and fused into the EPROMs. There used to be no mechanism to find what
More informationTyped Assembly Language for Implementing OS Kernels in SMP/Multi-Core Environments with Interrupts
Typed Assembly Language for Implementing OS Kernels in SMP/Multi-Core Environments with Interrupts Toshiyuki Maeda and Akinori Yonezawa University of Tokyo Quiz [Environment] CPU: Intel Xeon X5570 (2.93GHz)
More informationThe Art and Science of Memory Allocation
Logical Diagram The Art and Science of Memory Allocation Don Porter CSE 506 Binary Formats RCU Memory Management Memory Allocators CPU Scheduler User System Calls Kernel Today s Lecture File System Networking
More information0x0d2C May your signals all trap May your references be bounded All memory aligned Floats to ints round. remember...
Types Page 1 "ode to C" Monday, September 18, 2006 4:09 PM 0x0d2C ------ May your signals all trap May your references be bounded All memory aligned Floats to ints round remember... Non -zero is true ++
More informationHigh Performance Computing and Programming, Lecture 3
High Performance Computing and Programming, Lecture 3 Memory usage and some other things Ali Dorostkar Division of Scientific Computing, Department of Information Technology, Uppsala University, Sweden
More informationImportant From Last Time
Important From Last Time Embedded C Ø Pros and cons Macros and how to avoid them Intrinsics Interrupt syntax Inline assembly Today Advanced C What C programs mean How to create C programs that mean nothing
More informationQUIZ. What are 3 differences between C and C++ const variables?
QUIZ What are 3 differences between C and C++ const variables? Solution QUIZ Source: http://stackoverflow.com/questions/17349387/scope-of-macros-in-c Solution The C/C++ preprocessor substitutes mechanically,
More informationProcess Time. Steven M. Bellovin January 25,
Multiprogramming Computers don t really run multiple programs simultaneously; it just appears that way Each process runs to completion, but intermixed with other processes Process 1 6 ticks Process 2 Process
More informationECE 598 Advanced Operating Systems Lecture 4
ECE 598 Advanced Operating Systems Lecture 4 Vince Weaver http://www.eece.maine.edu/~vweaver vincent.weaver@maine.edu 28 January 2016 Announcements HW#1 was due HW#2 was posted, will be tricky Let me know
More informationCS510 Advanced Topics in Concurrency. Jonathan Walpole
CS510 Advanced Topics in Concurrency Jonathan Walpole Threads Cannot Be Implemented as a Library Reasoning About Programs What are the valid outcomes for this program? Is it valid for both r1 and r2 to
More informationENCM 501 Winter 2019 Assignment 9
page 1 of 6 ENCM 501 Winter 2019 Assignment 9 Steve Norman Department of Electrical & Computer Engineering University of Calgary April 2019 Assignment instructions and other documents for ENCM 501 can
More informationLast Time. Think carefully about whether you use a heap Look carefully for stack overflow Especially when you have multiple threads
Last Time Cost of nearly full resources RAM is limited Think carefully about whether you use a heap Look carefully for stack overflow Especially when you have multiple threads Embedded C Extensions for
More informationNational Aeronautics and Space and Administration Space Administration. cfe Release 6.6
National Aeronautics and Space and Administration Space Administration cfe Release 6.6 1 1 A Summary of cfe 6.6 All qualification testing and documentation is now complete and the release has been tagged
More informationDeveloping Reusable Device Drivers for MCU's
Embedded Systems Conference East 2012 Page 1 of 20 Developing Reusable Device Drivers for MCU's By Jacob Beningo www.beningo.com http://www.linkedin.com/in/jacobbeningo twitter : Jacob_Beningo EDN Blog
More informationSynchronization in Java
Synchronization in Java Nelson Padua-Perez Bill Pugh Department of Computer Science University of Maryland, College Park Synchronization Overview Unsufficient atomicity Data races Locks Deadlock Wait /
More informationOverview. This Lecture. Interrupts and exceptions Source: ULK ch 4, ELDD ch1, ch2 & ch4. COSC440 Lecture 3: Interrupts 1
This Lecture Overview Interrupts and exceptions Source: ULK ch 4, ELDD ch1, ch2 & ch4 COSC440 Lecture 3: Interrupts 1 Three reasons for interrupts System calls Program/hardware faults External device interrupts
More informationSpring 2017 :: CSE 506. Device Programming. Nima Honarmand
Device Programming Nima Honarmand read/write interrupt read/write Spring 2017 :: CSE 506 Device Interface (Logical View) Device Interface Components: Device registers Device Memory DMA buffers Interrupt
More informationImportant From Last Time
Important From Last Time Volatile is tricky To write correct embedded C and C++, you have to understand what volatile does and does not do Ø What is the guarantee that it provides? Don t make the 8 mistakes
More informationCSE 303: Concepts and Tools for Software Development
CSE 303: Concepts and Tools for Software Development Dan Grossman Spring 2007 Lecture 19 Profiling (gprof); Linking and Libraries Dan Grossman CSE303 Spring 2007, Lecture 19 1 Where are we Already started
More informationLectures 5-6: Introduction to C
Lectures 5-6: Introduction to C Motivation: C is both a high and a low-level language Very useful for systems programming Faster than Java This intro assumes knowledge of Java Focus is on differences Most
More informationCS-537: Midterm Exam (Fall 2008) Hard Questions, Simple Answers
CS-537: Midterm Exam (Fall 28) Hard Questions, Simple Answers Please Read All Questions Carefully! There are seven (7) total numbered pages. Please put your NAME and student ID on THIS page, and JUST YOUR
More informationImplementing Secure Software Systems on ARMv8-M Microcontrollers
Implementing Secure Software Systems on ARMv8-M Microcontrollers Chris Shore, ARM TrustZone: A comprehensive security foundation Non-trusted Trusted Security separation with TrustZone Isolate trusted resources
More informationMPLAB XC8 C Compiler Version 2.00 Release Notes for AVR MCU
MPLAB XC8 C Compiler Version 2.00 Release Notes for AVR MCU THIS DOCUMENT CONTAINS IMPORTANT INFORMATION RELATING TO THE MPLAB XC8 C COM- PILER WHEN TARGETING MICROCHIP AVR DEVICES. PLEASE READ IT BEFORE
More informationException Namespaces C Interoperability Templates. More C++ David Chisnall. March 17, 2011
More C++ David Chisnall March 17, 2011 Exceptions A more fashionable goto Provides a second way of sending an error condition up the stack until it can be handled Lets intervening stack frames ignore errors
More informationBoot Camp. Dave Eckhardt Bruce Maggs
Boot Camp Dave Eckhardt de0u@andrew.cmu.edu Bruce Maggs bmm@cs.cmu.edu 1 This Is a Hard Class Traditional hazards 410 letter grade one lower than other classes All other classes this semester: one grade
More informationI/O Devices. Nima Honarmand (Based on slides by Prof. Andrea Arpaci-Dusseau)
I/O Devices Nima Honarmand (Based on slides by Prof. Andrea Arpaci-Dusseau) Hardware Support for I/O CPU RAM Network Card Graphics Card Memory Bus General I/O Bus (e.g., PCI) Canonical Device OS reads/writes
More informationChapter 1: Why Program? Main Hardware Component Categories 8/23/2014. Main Hardware Component Categories: Why Program?
Chapter 1: Introduction to Computers and Programming 1.1 Why Program? Why Program? Computer programmable machine designed to follow instructions Program instructions in computer memory to make it do something
More informationCOMP322 - Introduction to C++ Lecture 02 - Basics of C++
COMP322 - Introduction to C++ Lecture 02 - Basics of C++ School of Computer Science 16 January 2012 C++ basics - Arithmetic operators Where possible, C++ will automatically convert among the basic types.
More informationLectures 5-6: Introduction to C
Lectures 5-6: Introduction to C Motivation: C is both a high and a low-level language Very useful for systems programming Faster than Java This intro assumes knowledge of Java Focus is on differences Most
More informationMartin Kruliš, v
Martin Kruliš 1 Optimizations in General Code And Compilation Memory Considerations Parallelism Profiling And Optimization Examples 2 Premature optimization is the root of all evil. -- D. Knuth Our goal
More informationSynchronization. Disclaimer: some slides are adopted from the book authors slides with permission 1
Synchronization Disclaimer: some slides are adopted from the book authors slides with permission 1 What is it? Recap: Thread Independent flow of control What does it need (thread private)? Stack What for?
More informationHave examined process Creating program Have developed program Written in C Source code
Preprocessing, Compiling, Assembling, and Linking Introduction In this lesson will examine Architecture of C program Introduce C preprocessor and preprocessor directives How to use preprocessor s directives
More informationCan Seqlocks Get Along with Programming Language Memory Models?
Can Seqlocks Get Along with Programming Language Memory Models? Hans-J. Boehm HP Labs Hans-J. Boehm: Seqlocks 1 The setting Want fast reader-writer locks Locking in shared (read) mode allows concurrent
More informationDeep C (and C++) by Olve Maudal
Deep C (and C++) by Olve Maudal http://www.noaanews.noaa.gov/stories2005/images/rov-hercules-titanic.jpg Programming is hard. Programming correct C and C++ is particularly hard. Indeed, it is uncommon
More informationWhat is uop Cracking?
Nehalem - Part 1 What is uop Cracking? uops are components of larger macro ops. uop cracking is taking CISC like instructions to RISC like instructions it would be good to crack CISC ops in parallel
More informationOther consistency models
Last time: Symmetric multiprocessing (SMP) Lecture 25: Synchronization primitives Computer Architecture and Systems Programming (252-0061-00) CPU 0 CPU 1 CPU 2 CPU 3 Timothy Roscoe Herbstsemester 2012
More informationCOS 318: Operating Systems. Overview. Andy Bavier Computer Science Department Princeton University
COS 318: Operating Systems Overview Andy Bavier Computer Science Department Princeton University http://www.cs.princeton.edu/courses/archive/fall10/cos318/ Logistics Precepts: Tue: 7:30pm-8:30pm, 105 CS
More informationCS 5220: Shared memory programming. David Bindel
CS 5220: Shared memory programming David Bindel 2017-09-26 1 Message passing pain Common message passing pattern Logical global structure Local representation per processor Local data may have redundancy
More informationCSE 153 Design of Operating Systems Fall 2018
CSE 153 Design of Operating Systems Fall 2018 Lecture 5: Threads/Synchronization Implementing threads l Kernel Level Threads l u u All thread operations are implemented in the kernel The OS schedules all
More informationIntroduction to Standard C++
Introduction to Standard C++ Lecture 00: Administravia + Language basics Massimiliano Culpo 1 1 CINECA - SuperComputing Applications and Innovation Department 07.04.2014 M.Culpo (CINECA) Introduction to
More informationProcess Coordination and Shared Data
Process Coordination and Shared Data Lecture 19 In These Notes... Sharing data safely When multiple threads/processes interact in a system, new species of bugs arise 1. Compiler tries to save time by not
More informationCS 31: Introduction to Computer Systems : Threads & Synchronization April 16-18, 2019
CS 31: Introduction to Computer Systems 22-23: Threads & Synchronization April 16-18, 2019 Making Programs Run Faster We all like how fast computers are In the old days (1980 s - 2005): Algorithm too slow?
More informationMy malloc: mylloc and mhysa. Johan Montelius HT2016
1 Introduction My malloc: mylloc and mhysa Johan Montelius HT2016 So this is an experiment where we will implement our own malloc. We will not implement the world s fastest allocator, but it will work
More informationCOS 318: Operating Systems
COS 318: Operating Systems Overview Kai Li Computer Science Department Princeton University (http://www.cs.princeton.edu/courses/cos318/) Important Times Lectures 9/20 Lecture is here Other lectures in
More informationRCU in the Linux Kernel: One Decade Later
RCU in the Linux Kernel: One Decade Later by: Paul E. Mckenney, Silas Boyd-Wickizer, Jonathan Walpole Slides by David Kennedy (and sources) RCU Usage in Linux During this same time period, the usage of
More informationCSci 4061 Introduction to Operating Systems. Programs in C/Unix
CSci 4061 Introduction to Operating Systems Programs in C/Unix Today Basic C programming Follow on to recitation Structure of a C program A C program consists of a collection of C functions, structs, arrays,
More informationThese are notes for the third lecture; if statements and loops.
These are notes for the third lecture; if statements and loops. 1 Yeah, this is going to be the second slide in a lot of lectures. 2 - Dominant language for desktop application development - Most modern
More informationCPSC/ECE 3220 Fall 2017 Exam Give the definition (note: not the roles) for an operating system as stated in the textbook. (2 pts.
CPSC/ECE 3220 Fall 2017 Exam 1 Name: 1. Give the definition (note: not the roles) for an operating system as stated in the textbook. (2 pts.) Referee / Illusionist / Glue. Circle only one of R, I, or G.
More informationQUIZ. What is wrong with this code that uses default arguments?
QUIZ What is wrong with this code that uses default arguments? Solution The value of the default argument should be placed in either declaration or definition, not both! QUIZ What is wrong with this code
More informationCSE 153 Design of Operating Systems
CSE 153 Design of Operating Systems Winter 19 Lecture 7/8: Synchronization (1) Administrivia How is Lab going? Be prepared with questions for this weeks Lab My impression from TAs is that you are on track
More informationFigure 1 Common Sub Expression Optimization Example
General Code Optimization Techniques Wesley Myers wesley.y.myers@gmail.com Introduction General Code Optimization Techniques Normally, programmers do not always think of hand optimizing code. Most programmers
More informationThreads. Concurrency. What it is. Lecture Notes Week 2. Figure 1: Multi-Threading. Figure 2: Multi-Threading
Threads Figure 1: Multi-Threading Figure 2: Multi-Threading Concurrency What it is 1. Two or more threads of control access a shared resource. Scheduler operation must be taken into account fetch-decode-execute-check
More informationMacros in C/C++ Computer Science and Engineering College of Engineering The Ohio State University. Lecture 33
Macros in C/C++ Computer Science and Engineering College of Engineering The Ohio State University Lecture 33 Macro Definition Directive: #define #define Example: #define BUFF_SIZE 1000 A
More informationAudience. Revising the Java Thread/Memory Model. Java Thread Specification. Revising the Thread Spec. Proposed Changes. When s the JSR?
Audience Revising the Java Thread/Memory Model See http://www.cs.umd.edu/~pugh/java/memorymodel for more information 1 This will be an advanced talk Helpful if you ve been aware of the discussion, have
More informationCS 326 Operating Systems C Programming. Greg Benson Department of Computer Science University of San Francisco
CS 326 Operating Systems C Programming Greg Benson Department of Computer Science University of San Francisco Why C? Fast (good optimizing compilers) Not too high-level (Java, Python, Lisp) Not too low-level
More informationCS-537: Midterm Exam (Fall 2013) Professor McFlub
CS-537: Midterm Exam (Fall 2013) Professor McFlub Please Read All Questions Carefully! There are fourteen (14) total numbered pages. Please put your NAME (mandatory) on THIS page, and this page only. Name:
More informationCS-537: Midterm Exam (Spring 2009) The Future of Processors, Operating Systems, and You
CS-537: Midterm Exam (Spring 2009) The Future of Processors, Operating Systems, and You Please Read All Questions Carefully! There are 15 total numbered pages. Please put your NAME and student ID on THIS
More informationUsing Weakly Ordered C++ Atomics Correctly. Hans-J. Boehm
Using Weakly Ordered C++ Atomics Correctly Hans-J. Boehm 1 Why atomics? Programs usually ensure that memory locations cannot be accessed by one thread while being written by another. No data races. Typically
More informationCS-537: Midterm Exam (Spring 2001)
CS-537: Midterm Exam (Spring 2001) Please Read All Questions Carefully! There are seven (7) total numbered pages Name: 1 Grading Page Points Total Possible Part I: Short Answers (12 5) 60 Part II: Long
More informationCS Programming In C
CS 24000 - Programming In C Week Two: Basic C Program Organization and Data Types Zhiyuan Li Department of Computer Science Purdue University, USA 2 int main() { } return 0; The Simplest C Program C programs
More informationOperating Systems (ECS 150) Spring 2011
Operating Systems (ECS 150) Spring 2011 Raju Pandey Department of Computer Science University of California, Davis CA 95616 pandey@cs.ucdavis.edu http://www.cs.ucdavis.edu/~pandey Course Objectives After
More informationComputer Fundamentals: Operating Systems, Concurrency. Dr Robert Harle
Computer Fundamentals: Operating Systems, Concurrency Dr Robert Harle This Week The roles of the O/S (kernel, timeslicing, scheduling) The notion of threads Concurrency problems Multi-core processors Virtual
More informationMISRA-C. Subset of the C language for critical systems
MISRA-C Subset of the C language for critical systems SAFETY-CRITICAL SYSTEMS System is safety-critical if people might die due to software bugs Examples Automobile stability / traction control Medical
More informationParallel Programming: Background Information
1 Parallel Programming: Background Information Mike Bailey mjb@cs.oregonstate.edu parallel.background.pptx Three Reasons to Study Parallel Programming 2 1. Increase performance: do more work in the same
More informationParallel Programming: Background Information
1 Parallel Programming: Background Information Mike Bailey mjb@cs.oregonstate.edu parallel.background.pptx Three Reasons to Study Parallel Programming 2 1. Increase performance: do more work in the same
More informationDesign and development of embedded systems for the Internet of Things (IoT) Fabio Angeletti Fabrizio Gattuso
Design and development of embedded systems for the Internet of Things (IoT) Fabio Angeletti Fabrizio Gattuso Why C? Test on 21 Android Devices with 32-bits and 64-bits processors and different versions
More informationCompiler Theory. (GCC the GNU Compiler Collection) Sandro Spina 2009
Compiler Theory (GCC the GNU Compiler Collection) Sandro Spina 2009 GCC Probably the most used compiler. Not only a native compiler but it can also cross-compile any program, producing executables for
More informationUM1584 User manual Standard software driver for C90LC Flash in SPC560xx, SPC56APxx and SPC563M64xx Introduction
User manual Standard software driver for C90LC Flash in SPC560xx, SPC56APxx and SPC563M64xx Introduction This document is the user manual for the Standard Software Driver (SSD) for C90LC Flash in SPC560Bxx,
More informationEE475 Lab #3 Fall Memory Placement and Interrupts
EE475 Lab #3 Fall 2005 Memory Placement and Interrupts In this lab you will investigate the way in which the CodeWarrior compiler and linker interact to place your compiled code and data in the memory
More informationSanitizing Sensitive Data: How to get it Right (or at least Less Wrong ) Roderick Chapman, 14th June 2017
Sanitizing Sensitive Data: How to get it Right (or at least Less Wrong ) Roderick Chapman, 14th June 2017 Contents The problem Technical issues Design goals Ada language support A policy for sanitization
More informationIntroduction to Computer Systems
Introduction to Computer Systems Today: Welcome to EECS 213 Lecture topics and assignments Next time: Bits & bytes and some Boolean algebra Fabián E. Bustamante, Spring 2010 Welcome to Intro. to Computer
More information