OK, this might be a very general question but I'm not to familiar with the topic and happy for any hint.
I have a Cross Compiling tool chain from SoucereyCodeBench for ARM ( arm-xilinx-linux-gnueabi-). I cross compiled a library which uses the compiler Options: -DSC_INCLUDE_FX -DSC_USE_PTHREADS -pthreads -fPIC -DPIC
So if I want to use the libary for bare metal program I would need pthreads for the bare metal compiler (arm-xilinx-eabi-) I guess?
Otherwise my program probally wouldn't run or compile in the first place. So could it be done to compile pthreads for bare metal?
Threads and Bare Metal
Bare metal programming targets only provide what you put on them. The pthread implementation most folks are familiar with is the Linux NPTL version, which works because the Linux kernel and the GNU C library make it work. On bare metal targets, you don't get the benefit of either the Linux kernel or the GNU C library. You'll have to bring your own bare metal thread library and runtime but at that point you may be better off using an RTOS that provides threads.
A Note on Toolchain Prefixes
The gcc toolchain prefix, arm-xilinx-linux-gnueabi-, indicates the target as ARM Linux, not bare-metal. The arm-xilinx-linux-gnueabi- toolchain will build pthread aware code (-lpthread) but it will assume that the Linux target has the pthread library and other necessary software layers already installed.
If instead you switch to the bare-metal version of the gcc ARM xilinx toolchain, your toolchain prefix will be arm-xilinx-eabi-. Everything I said above about bare metal and threads will apply.
I think it will be a matetr of porting your code rather than simply cross-compiling it unchanged. As its name suggests POSIX threads (pthreads) assumes a POSIX API.
If you need threads on a bare metal ARM target, the you at least need some sort of thread scheduling libraries of which there are many. Most RTOSs are not full OSs in the sense of Linux, but rather simple schedulers with IPC mechanisms that link as static libraries like any other to your monolithic application - that probably still counts as "bare metal" in the sense that the system boots directly to your main() function where you are responsible for creating tasks/threads and starting the scheduler.
Some RTOSs support POSIX APIs and therefore pthreads, but these tend to be the larger more complete OSs rather than simple schedulers - either way they are generally smaller and more scalable then Linux so may meet yout "bare metal" requirements nonetheless.
Of course nothing stops you from creating a wrapper around any RTOS library to provide a pthread compatible API that might make porting your code simpler.
Related
I realize this may be a really dumb question. Please humor me:
True or False: The only way to compile a program to run on a VxWorks platform is to purchase a development environment like Tornado or Workbench from WindRiver.
(I'm looking for an free/open-source solution to compile for a VxWorks platform.)
Outside of an academic license (which would use a VxWorks installation anyway), there is not any way to legally compile your code for a vxWorks platform.
Technically, you CAN obtain the GNU toolchain used to compile code for VxWorks.
The issue you will run into is that you won't have access to the header files necessary for compiling your code or the libraries to link against.
One can use a generic GNU cross-compiler to generate ELF files, and load them onto a running VxWorks system using the ld command. However, I don't recommend it for anything beyond proof-of-concept or initial experimentation -- the VxWorks libraries and Wind River's superb documentation of them are both necessary.
On the development host:
powerpc-elf-eabi-gcc -c foo.c
Then on the target-resident shell, that has mounted a filesystem from the development host (for example, over NFS):
-> ld < foo.o
-> main()
(Where the function main() comes from foo.c)
Since VxWorks is proprietary, they made it so you need their tools (Workbench/Tornado), which they supply, in order to develop for their OS.
I find KDevelop a very good IDE overall and I already have a good experience using it for cross-compiling and debugging software for ARM9 CPUs running embedded Linux. Now that I got some Arduino boards for smaller projects, I found them a very nice and easy platform, but its IDE is far behind Kdevelop in functionality, code introspection and so on, so I'd like to adapt Kdevelop to compile and program arduino boards instead.
The goal is to enable software development in pure C/C++ or regular C++ using arduino libraries as well (this answer helps a lot in making this possible), bypassing arduino's artificial limitations imposed to make it easy for begginers. I intend to use CMake as the build system, for it integrates well with Kdevelop and allows for easy cross-compilation. As a side note, you could use this toolchain file for making CMake use the avr-gcc cross-compiler:
INCLUDE(CMakeForceCompiler)
# the name of the target operating system
#SET(CMAKE_SYSTEM_NAME Linux)
# which C and C++ compiler to use
CMAKE_FORCE_C_COMPILER(avr-gcc GNU)
CMAKE_FORCE_CXX_COMPILER(avr-g++ GNU)
# here is the target environment located
SET(CMAKE_FIND_ROOT_PATH /usr/avr)
# adjust the default behaviour of the FIND_XXX() commands:
# search headers and libraries in the target environment, search
# programs in the host environment
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
Since arduino uses avr-gcc and avrdude behind the scenes to compile and program the target AVR microcontrollers, I found some interesting directions such as AVR Tutorial, Programming Arduino Uno in pure C and Program Arduino with AVR-GCC, but I still don't know how to add a button on Kdevelop's interface to call avrdude in order to upload the compiled binary to the microcontrollers' flash memory. Anyone can help me out doing that?
Having server x86/x64, how best develop software under AIX6/7 on C++?
Someone personally tried to do it and that advise from personal experience:
Can have any IBM compilers for x64, which ensures portability compilation on PowerPC AIX or can be have a virtual machine under Windwos x64 with emulate PowerPC x64 to install AIX and compile under it, or may be better buy cloud's service with AIX to develop and where can I do it?
As I know QEMU does not support AIX.
What do you say about Simics, OVPSim and Bochs or other?
I'm not clear on the question but if you don't have the AIX include files, you are going to have trouble trying to develop code that will compile on AIX. AIX often throws in some oddity that needs to be worked around in the include files.
As far as which compiler, I use gcc. Start by pulling down the gcc from IBM: http://www-03.ibm.com/systems/power/software/aix/linux/toolbox/ezinstall.html Then pick a GCC and compile it using the GCC you pulled down. Then use the new GCC for your development. An alternative would be to pull down the GCC from perzl: http://www.perzl.org/aix/index.php?n=Main.Gcc -- I've never tried that but I've heard good things about them.
Hope this helps
Update to Alex:
Yes. As mentioned, the gcc supplied by IBM will give you fits but it is good enough to compile your own gcc which will then be very stable. I've written device drivers using C++ for AIX, used g++, and included parts of Boost.
gcc/g++ for AIX is very stable and complete if compiled properly. Aside from that project, I have about 50 open source packages working on AIX. Most are C and not C++ but in general, if you are doing open source, gcc on AIX will give you less obstacles than xlc. Not xlc's fault. Its just what the developers assume. Like perzl, I use to upload my images as installp install images but had no users so I stopped.
Last: the customary warning is to not use GNU's ld. Use AIX's ld and assembler (as) but you can find threads that will contradict this. I have not seriously tried GNUs ld although I took a stab at it once about 6 months ago and then got side tracked.
Two of my projects you might want to look at:
https://github.com/pedz/aix-build-scripts -- this is a (probably hard to follow) set of scripts to start from ground zero and get you rolling compiling open source projects on AIX.
https://github.com/pedz/aixbin -- This is a set of two scripts that I now have ambivalent feelings about. Many open source projects (Ruby in particular) need these scripts but others (GNU Emacs) will fail if they are used.
I have been researching Golang and I see that it has a compiler.
But is it compiling Go into assembly level code or just converting it into BYTECODES and then calling that compilation? I mean, even in PHP we are able to convert it into BYTECODES and have faster performance.
Is Golang a REPLACEMENT for system level programming and compiling ?
This is really a compiler (in fact it embbeds 2 compilers) and it makes totally self sufficient executables. You don't need any supplementary library or any kind of runtime to execute it on your server. You just have to have it compiled for your target computer architecture.
From the documentation :
There are two official Go compiler tool chains. This document focuses
on the gc Go compiler and tools (6g, 8g etc.). For information on how
to work on gccgo, a more traditional compiler using the GCC back end,
see Setting up and using gccgo.
The Go compilers support three instruction sets. There are important
differences in the quality of the compilers for the different
architectures.
amd64 (a.k.a. x86-64); 6g,6l,6c,6a
A mature implementation. The
compiler has an effective optimizer (registerizer) and generates good
code (although gccgo can do noticeably better sometimes).
386 (a.k.a. x86 or x86-32); 8g,8l,8c,8a
Comparable to the amd64 port.
arm (a.k.a. ARM); 5g,5l,5c,5a
Supports only Linux binaries. Less widely used than
the other ports and therefore not as thoroughly tested.
Except for
things like low-level operating system interface code, the run-time
support is the same in all ports and includes a mark-and-sweep garbage
collector, efficient array and string slicing, and support for
efficient goroutines, such as stacks that grow and shrink on demand.
The compilers can target the FreeBSD, Linux, NetBSD, OpenBSD, OS X
(Darwin), and Windows operating systems. The full set of supported
combinations is listed in the discussion of environment variables
below.
On a server you'll usually target the amd64 platform.
Note that Go is well known for the speed of compilation. When deploying my server programs, I don't build for the different platforms on the development computer : I deploy the sources and I compile directly on the production servers. Since Go1 I never had a code compiling on one platform and not compiling on the other ones.
On Windows I had no problem in making an exe on my development computer and simply sending this exe to people never having installed anything Go related.
Go compiles quickly to machine code yet has the convenience of garbage collection and the power of run-time reflection. It's a fast, statically typed, compiled language that feels like a dynamically typed, interpreted language.
Source - golang.org
Golang is a compiler-based language, it can easily be compiled on the development computer for any targeted system such as linux and mac.
A golang project when have compiled turns to a self-sufficient executable and can be ran on the targeted system without anything additional. It's because the golang compiler turns your code into bytes ready to execute on a system which can run compiled c code.
I am a newbie to embedded developement, as figure shown. I have a small ARM board, AT91SAM7-EX256. I have also a JTAG programmer dongle, too. I am using Linux (Ubuntu x86_32) on my notebook and desktop machine. I'm using CodeSourcery Lite for cross-compiling to ARM-Linux.
Am I right that I can't use this Linux-target cross-compiler to make binary or hex files for the small ARM board (it comes without any operating system)? Should I use the version called ARM EABI instead?
As I see, it's a "generic" ARM compiler. I've read some docs, and there're lot of options to specify the processor type and instruction set (thumb, etc.), there will be no problem with it. But how can I tell the compiler, how should the image (bin/hex) looks like for the specific board (startup, code/data blocks etc.)? (In assemblers, there're the org and load directives for it.)
What software do I need to capture some debug messages from the board on my PC? I don't want to on-board debugging, I just need some detailed run-time signal, more than just blinking leds.
I have an option to use MS-Windows, I can get a dedicated machine for it. Do you recommend it, is it much easier?
Can I use inline assembly somehow in my C code? I dunno anything about that. Can I use C++ or just C?
I have also a question, which don't need to answer: are there really 4096 kind of GNU compilers and cross-compilers (from Linux_x86_32 -> Linux_x86_32, Linux_x86_32 -> Linux_ARM, OSX -> Linux_ARM, PPC_Linux -> OSX) and 16 different GNU compiler sources (as many target platforms/processors exists) around? The signs says "yes", but I can't believe it. Correct me, and show me the GNU compiler which can produce object file for any platform/processor, and the universal linker which can produce executable for any platform.
While Windows is not a "better" platform do this kind of embedded development on, it may be easier to start with since you can get a pre-built environment to work with. For example, Yagarto (which I would recommend).
Setting up an embedded development environment on Linux can require a considerable amount of knowledge, but it's not impossible.
To answer your questions:
Your Linux cross-compiler comes with libraries to build executables for a Linux environment. You have hinted that you want to build a bare-metal executable for this board. While you can do this with your compiler, it will just confuse things. I recommend building a baremetal cross-compiler. Since you're building your own baremetal executable (and thus you are the operating system, the ABI doesn't matter since you're generating all of the code and not interoperating with other previously built code.
There are several versions of the ARM instruction set (and Thumb). You need to generate code for your particular processor. If you generate the code for a newer version of the instruction set, you will likely generate code which generates a reserved instruction exception. Most prebuilt gcc cross-compiler toolchains for ARM are "multilib" and will build for a variety of architectures in both ARM and Thumb.
Not sure exactly what you're looking for here. This is a bare metal platform. You can use the debugger channel to send messages if you're debugging on target, or you'll need to build your own communication channel into the firmware you write (i.e. uart support).
See above.
Yes. See here for details on gcc's extended inline assembly syntax. You can do this in C++ and C. You can also simply link pure assembly files.
There is no universal gcc compiler / linker. You need a uniquely built compiler for each host / target combination you use.
Finally, please take a look at Atmel's documentation. They have a wealth of information on developing for this target as well as a board package with the needed linker directives and example programs. Note of course the package is for Atmel's own eval board, but it will get you started.
http://sam7stuff.blogspot.com/
I use either of the codesourcery lite versions. But I have no use for the gcc library nor a C library, I just need a compiler.
In the gcc 3 days newlib was great, modify two files worth of system support (simple open, close, read, putc type stuff) and you could compile just about anything, but with gcc 4.x you cannot even go back and cross compile gcc 3.x, you have to install an old linux distro in a virtual machine.
To get the gcc library yes you probably want to use the eabi version not the version with linux gnueabi in the file names.
You might also consider llvm (if you dont need a C library, and you will still need binutils), hmm, I wonder if newlib compiles with llvm.
I prefer to avoid getting trapped in sandboxes, learn the tools and how to manipulate the linker, etc to build your binaries.