C/C++ News - Page 15 of 15 - CNX Software

December 12, 2011July 17, 2012 by Jean-Luc Aufranc (CNXSoft) - 3 Comments

Design West Summit – 26-29 March 2012

UBM Design announced the schedule and pass pricing for Design West Summit (previously Embedded System Conference) which will now bring 7 summits in one location (San Jose McEnery Convention Center) on 26-29 March 2012: Embedded Systems Conference & Exhibition – Conference Dates: March 26 – 29, 2012. Exhibition Dates: March 27-29, 2012. (See Details below) Android Summit – March 28, 2012 – Everything Android from embedded design to Apps development. Android Certification Program Android Speed Training Android Fundamentals Course on the Expo Floor Android Conference Program Multicore DevCon– March 27 & 28, 2012 – Embedded multicore and multimedia. 7th annual Multicore Conference Courses Multicore Expo Floor Zone Multicore Fundementals Courses Keynote Addresses Industry Addresses Expo floor parties and giveaways BlackHat – March 29, 2012 – One-day conference focused on security in embedded systems. Security Fundementals Course Black Hat Summit Conference Courses Security focused presentations in the expo floor theater Keynotes […]

November 29, 2011 by Jean-Luc Aufranc (CNXSoft) - 4 Comments

ARM Releases Free DS-5 Community Edition For Android Developers

ARM announced a free version of its Eclipse-based DS-5 tools for small development firms (with 10 or fewer developers) and individuals who publish applications for Android. The ARM Development Studio 5 (DS-5) Community Edition (CE) helps create performance- and power-optimized native software by integrating a graphical debugger for code generated for the Android Native Development Kit (NDK) and a basic version of the ARM Streamline performance analysis tool. DS-5 CE is designed to work with Android Virtual Devices ( AVDs), development boards and devices that run Android 2.2 and API 8 or higher. ARM Development Studio 5 (DS-5) Community Edition is distributed as plug-in for Eclipse and completes the app developer toolkit with a C, C++ and Assembly graphical debugger that builds on the Android Debug Bridge (ADB), a software performance profiler and system analyzer (ARM Streamline). To get started, you’ll need Eclipse IDE, the Android SDK and the Android NDK […]

November 27, 2011November 27, 2011 by Jean-Luc Aufranc (CNXSoft) - 1 Comment

ARM NEON Tutorial in C and Assembler

The Advanced SIMD extension (aka NEON or “MPE” Media Processing Engine) is a combined 64- and 128-bit single instruction multiple data (SIMD) instruction set that provides standardized acceleration for media and signal processing applications similar to MMX, SSE and 3DNow! extensions found in x86 processors. Doulos has a video tutorial showing how you can exploit NEON instructions in assembler, how to modify your C code and provides the compile options for gcc to enable NEON during the build. Abstract: With the v7-A architecture, ARM has introduced a powerful SIMD implementation called NEON™. NEON is a coprocessor which comes with its own instruction set for vector operations. While NEON instructions could be hand coded in assembler language, ideally we want our compiler to generate them for us. Automatic analysis whether an iterative algorithm can be mapped to parallel vector operations is not trivial not the least because the C language is […]

November 7, 2011November 7, 2011 by Jean-Luc Aufranc (CNXSoft) - 1 Comment

Development Testing with Static Analysis

I’ve recently come across an EE Times article written by Coverity stressing the benefits of static analysis and how it can help finding potential issues in the code early. They mentioned 3 static analysis techniques: Dataflow analysis This technique can find the defect in the listing below during compile time.

void null_pointer_deref(int x)
{
    char *p;
    if (x == 0) {
        p = foo();
    } else {
        p = 0;
    }
    if(x != 0) {
        *p;
    } else {
        ...
    }
}

void null_pointer_deref(int x)

{

char *p;

if (x == 0) {

p = foo();

} else {

p = 0;

}

if(x != 0) {

*p;

} else {

...

}

If value of x passed into the function is not zero, p is assigned a null pointer with p=0. Then, the next conditional check (x!=0) takes a true branch and in the next line p is dereferenced, leading to a null pointer dereference. This type of issue can be detected at compiled time with dataflow analysis. Interprocedural analysis This technique can find defects across function and method boundaries. See listing below:

void *zero_alloc(size_t size) {
    void *p = malloc(size);
    if (!p) return NULL; 

    memset(p,0,size);
    return p;
}

struct S *create_S(int initial_value) { 
    struct S *s = (struct S *) zero_alloc(sizeof(*s));
    if (!s) return NULL;
    s-&gt;field = initial_value;
    return s;
}

int example_leak(struct S *s, int value) {
    struct S *tmp = s;
    if(!tmp) {
       tmp = create_S(value);
    }
    if(!tmp) return -1;
    ...
    return 0;
}

void *zero_alloc(size_t size) {

void *p = malloc(size);

if (!p) return NULL;

memset(p,0,size);

return p;

}

struct S *create_S(int initial_value) {

struct S *s = (struct S *) zero_alloc(sizeof(*s));

if (!s) return NULL;

s->field = initial_value;

return s;

}

int example_leak(struct S *s, int value) {

struct S *tmp = s;

if(!tmp) {

tmp = create_S(value);

}

if(!tmp) return -1;

...

return 0;

}

There are 3 functions: example_leak, create_S and zero_alloc. Interprocedural analysis can go through the code and identify the memory leak. The analysis engine has to trace the […]

October 17, 2011October 17, 2011 by Jean-Luc Aufranc (CNXSoft) - 3 Comments

LLVM (Low Level Virtual Machine) Compiler Infrastructure

The Low Level Virtual Machine (LLVM) is a compiler and toolchain infrastructure, written in C++, designed for compile-time, link-time, run-time, and “idle-time” optimization of programs written in arbitrary programming languages. Originally implemented for C/C++, LLVM is now used with a variety programming languages such as Python, Ruby and may others. Code in the LLVM project is licensed under the “UIUC” BSD-Style license. LLVM can be used to replace and/or supplement the GNU tools such as gcc, g++, gdb, etc… LLVM now consists of a number of different sub-projects including: The LLVM Core libraries provide a source- and target-independent optimizer, along with code generation support for many popular CPUs. These libraries are built around a well specified code representation known as the LLVM intermediate representation (“LLVM IR”). The LLVM Core libraries are well documented, and it is particularly easy to invent your own language (or port an existing compiler) to use […]

October 3, 2011August 15, 2013 by Jean-Luc Aufranc (CNXSoft) - 16 Comments

Cross Compiling Boost C++ Libraries for ARM

Boost provides free peer-reviewed portable C++ source libraries. Ten Boost libraries are already included in the C++ Standards Committee’s Library Technical Report and will be in the new C++11 Standard. The Boost C++ libraries are already included in popular Linux and Unix distributions such as Fedora, Debian, Ubuntu and NetBSD and are used by projects such as Python, Xibo, Civilization IV, etc.. Here are the steps to cross-compile Boost C++ libraries for arm using arm-linux-guneabi-g++: Download the source code:

wget http://sourceforge.net/projects/boost/files/boost/1.47.0/boost_1_47_0.tar.bz2/download

1	wget http://sourceforge.net/projects/boost/files/boost/1.47.0/boost_1_47_0.tar.bz2/download

Extract the source code:

mv download boost.tar.bz2
tar xjvf boost.tar.bz2
cd boost_1_47_0/

mv download boost.tar.bz2

tar xjvf boost.tar.bz2

cd boost_1_47_0/

Bootstrap the code:

./bootstrap.sh

1	./bootstrap.sh

Modify the configuration file (project-build.jam) to use the ARM toolchain by replacing the line with “using gcc” by:

using gcc : arm : arm-linux-gnueabi-g++ ;

1	using gcc : arm : arm-linux-gnueabi-g++ ;

Install the python development package:

sudo apt-get install python-dev

1	sudo apt-get install python-dev

Build and install the boost libraries:

./bjam install toolset=gcc-arm --prefix=~/edev/beagleboard/libs --disable-long-double -sNO_ZLIB=1 -sNO_BZIP2=1

1	./bjam install toolset=gcc-arm --prefix=~/edev/beagleboard/libs --disable-long-double -sNO_ZLIB=1 -sNO_BZIP2=1

This was tested in Ubuntu 11.04 (natty) and 10.04 LTS with linaro g++ toolchain. Jean-Luc Aufranc (CNXSoft)Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his […]

September 13, 2011September 13, 2011 by Jean-Luc Aufranc (CNXSoft) - 4 Comments

Best Practices for Writing Safer C Code

Thomas Honold wrote an article published on EETimes giving 17 steps to safer C code. Not only this article provides tips to write safer C code, but I believe those steps are simply best practices when writing C code for embedded systems as they shorten the software life cycle by making it easier for a software team to write, debug and maintain code and by improving the software QA procedure. Here’s a summary of the 17 steps to achieve safer C code: Follow the rules you’ve read a hundred times: Initialize variables before use. Do not ignore compiler warnings. Check return values. Use enums as error types. Define an ENUM_MAX value at the end, so that the code to check the range does not have to be modified each time you add a new error code. Expect to fail Always assume there will be an error and set to default […]

September 12, 2011 by Jean-Luc Aufranc (CNXSoft) - No Comments

What Programming Language Should I Learn ?

“What programming language should I learn ?” is a question often asked by people new to software development. The answer is always “it depends”. But for embedded systems, it seems C language is a must as you can see in the chart below (Source: “The 2011 Embedded Market Study” by Embedded.com). For the 2011 survey, 1886 respondents from across the embedded industry answered that their embedded project was mostly programmed in C language (62%), followed by C++ (22%), assembler (5%) and Java (2%). The other languages were all under 1%. Jean-Luc Aufranc (CNXSoft)Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011. www.cnx-software.com