Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
We don’t allow questions seeking recommendations for books, tools, software libraries, and more. You can edit the question so it can be answered with facts and citations.
Closed 4 years ago.
Improve this question
i am very new to assembly programming language. i have a little experience with MASM which works on windows. i want to know how to deal with GUI in Linux.(i have done simple programs in assembly on Linux using gcc) i would like if some one can give me any resources particularly coding samples.
Thanks !!
You'll want:
NASM: A cross platform assembler
GTK+: a C GUI library
Ubuntu: The most popular desktop Linux distribution
An example of GTK in use with NASM on Linux
If you want to go "low level", there is (or used to be) https://en.wikipedia.org/wiki/Direct_Graphics_Access on Linux + XFree86 (now called X.org).
You could map the framebuffer into user-space and draw on it with loads/stores, instead of read/write system calls on sockets (the end result of GTK+ function calls is normally talking to the X server over a socket).
Or there are various libraries that allow more or less direct access to video RAM and video modes when your program is running on a virtual console with no X server (or other display server like Wayland).
https://en.wikipedia.org/wiki/Virtual_console#Interface mentions DirectFB, DRI, SDL and the old SVGALib.
Changing video modes will normally still require a system call, but you can load/store to video RAM. Different libraries presumably have different ways for dealing with vsync / double-buffering / whatever.
This isn't necessarily faster or better: modern graphics cards are much more than dumb framebuffers. They have GPU hardware that can accelerate graphics operations, and storing directly to video RAM doesn't take advantage of it.
But if you really want to play around with direct access to video RAM, those links should be a good starting point for making it happen in user-space on a virtual console under Linux, with hopefully less risk of locking up the whole machine when your program has a bug.
(Be ready to SSH in from another machine and kill your process + chvt, though. And make sure you enable the magic SysRQ keys for killing all processes on the current console, and for "unRaw" keyboard input.
Disclaimer: I have not personally written software that does this, but there are some examples like FBI (framebuffer image viewer). I have recovered the console with ssh and/or SysRQ without rebooting after using buggy software and/or buggy drivers, though.
Related
Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 4 years ago.
Improve this question
Background information on the architecture: I just designed a set of instructions for a CPU that I'm going to put in an FPGA, but I want to be able to do it compatible with Linux (a simple Linux system) but I just started with this and I do not know much about this, I'm sure Linux can serve in my CPU. I think AVR supports Linux too, but I do not know if this is true but if this is true I think my CPU can also.
My CPU is 16 bits, and it has the following registers:
AX
BX
CX
DX
EX
FX
This can support up to 256 (16-bits registers), I also only put a few registers because I do not know if it will give me space for the VGA driver in my FPGA, think that 8 registers more could fit in the register file. My FPGA board has a Cyclone IV.
The program counter
or (PC) of my CPU is 16 bits.
My CPU handles data with Pointers (ARP, BRP) that point to two registers and take the value of the registers to the two outputs that can be used to put the values (A, B) of the ALU. To save data in the registers I use two pointers as well (CRP, DRP) with these I point to the registers where the values will be stored, the instructions say if the pointers are going to be used to save a value because otherwise, the value would be saved in two registers by mistake.
I do not know if this information is useful to give you an idea if I'm going to be able to use Linux in my design.
Thank you so much! ☺
Question: Is it possible to port Linux to a 16bit architecture?
Edit: After almost 3 years of gained experience with embedded systems, I see how ignorant this question is. I cannot provide an answer to this question because this question is flagged to not accept answers. But I will try to explain why porting Linux natively to a 16bit CPU is almost impossible.
Real Linux requires MMU to work, although there is uClinux which requires no MMU. MMU is required to provide userspace programs with their own memory address space without other programs interfering.
16bit address space is too limited to even run what is required. As the smaller Linux installations that I've seen need 8MB which is way off the 16bit address space (64 kilobytes).
Linux kernel needs Binutils and GCC to compile!
It will be very hacky and tricky to port GCC because GCC was designed to target 32bit architectures.
I mentioned earlier that it's almost impossible but, you can do emulation and with help of external hardware, you can emulate another architecture. But that's cheating, isn't it?
http://dmitry.gr/index.php?r=05.Projects&proj=07.%20Linux%20on%208bit
Finally, if you really want to run Linux on your custom CPU, start with RISCV. It supports GCC and all the required tools, plus RISCV is the future!
If you really want to run an OS in your custom CPU, you can port it to the LCC compiler. Run RTOS. This is a more realistic approach. But still, it is a challenging one.
You are out of luck. Linux requires a 32 bit system to run.
Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 9 years ago.
Improve this question
I understand that the answer to this question, like most, is "it depends", but what I am looking for is not so much an answer as much as a rationale for the different things affecting the decision.
My use case is that I have an ARM Cortex A8 (TI AM335x) running an embedded device. My options are to use some embedded linux to take advantage of some prebuilt drivers and other things to make development faster, but my biggest concern for this project is the speed of the device. Memory and disk space are not much of a concern. I think it is a safe assumption that programming directly against the mpu and not using a full OS would certainly make the application faster, but gaining a 1 or 2 percent speedup is not worth the extra development time.
I imagine that the largest slowdowns are going to come from the kernel context switching and memory mapping but I do not have the knowledge to correctly assess or gauge the extent of those slowdowns. Any guidance would be greatly appreciated!
Your concerns are reasonable. Going bare metal can/will improve performance but it may only be a few percent improvement..."it depends".
Going bare metal for something that has fully functional drivers in linux but no fully functional drivers bare metal, will cost you development and possibly maintenance time, is it worth that to get the performance gain?
You have to ask yourself as well am I using the right platform, and/or am I using the right approach for whatever it is you want to do on that processor that you think or know is too slow. Are you sure you know where the bottleneck is? Are you sure your optimization is in the right place?
You have not provided any info that would give us a gut feel, so you have to go on your gut feel as to what path to take. A different embedded platform (pros and cons), bare metal or operating system. Linux or rtos or other. One programming language vs another, one peripheral vs another, and so on and so on. You wont actually know until you try each of these paths, but that can be and likely is cost and time prohibitive...
As far as the generic title question of os vs bare metal, the answer is "it depends". The differences can swing widely, from almost the same to hundreds to thousands of times faster on bare metal. But for any particular application/task/algorithm...it depends.
Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
We don’t allow questions seeking recommendations for books, tools, software libraries, and more. You can edit the question so it can be answered with facts and citations.
Closed 5 years ago.
Improve this question
On windows CHM is a very good option.
Is there anything other then delivering a static set of HTML pages and using a primitive call to a webbrowser (which is even a problem itself on linux). And it would not offer any kind of fulltext searching, separated bookmarks and even the simple fact of not opening a new tab for each help call.
The Gnome yelp program is what is used for GTK/Gnome applications. It supports a number of formats, but not CHM directly. They have started to define their own markup, named Mallard. But I don't know what is the status of that.
I'd still recommend static HTML as the best option (and of course man pages!). For example you can use Sphinx to write beautiful documentation with a full-text search support!
There are CHM viewers available on Linux though frankly as a Linux user I'd prefer to get static HTML pages.
Some examples are chmsee and kchmviewer.
Afaik there is no universal system. Depending on your desktop system (gnome/kde) there might be helpsystems, but they are usually based on loose files and use full-blown browsers. (usually webkit based)
For Lazarus a CHM based helpsystem and embedded browser was created, including CHM write support.
The reasons to avoid loose static html were mostly:
the 60000 lemma static documentation took too long to install on lighter systems or systems with specialist filesystems.
CHM removes slack and adds compression.
we also support non posix and OS X systems, and little filesystem related problems (charsets/encoding, separators, path depth etc) and case insenstive filesystems on *nix caused a lot of grief. The CHM based help solved that, allowing for one set of routines to access helpdata on all systems.
indexing and toc are Btree based, and can be easily merged runtime from independently produced help sets. In general integrating independently produced helpfiles is a underappreciated aspect of helpfiles in general, while key to open platforms.
native fulltext search.
An own viewer also has the ability to take advantage of extra features on top of the base system.
I'm not mentioning the Lazarus system in the hope you adapt it, since it is at the moment too much a development system (SDK) oriented system, the viewer is not even available as a separate package. I mainly mention it to illustrate the problems of loose html.
I haven't investigate KDE/Gnome/Eclipse what they use as helpsystem for a while though. If I would have to restart from scratch, that's where I would look first.
If I had to create something myself quickly, I would use zipped static html, and a single gziped file with metadata/indexes and the lightest browser (Konquerer?) I could find. Not ideal, not like Windows, but apparently the best Linux can offer.
Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
We don’t allow questions seeking recommendations for books, tools, software libraries, and more. You can edit the question so it can be answered with facts and citations.
Closed 7 years ago.
Improve this question
I am eager to find a tool that allows me to trace the behaviour of the pthreads in a program I am working on. I am aware that there where similar questions asked before, see here and here .
As it turns out, the tools that are recommended are not what I need or it seems impossible to get them to to work on my machine. It is Debian 6, 32-bit all over on x86 architecture.
EZtrace in combination with ViTE seems to be what I am looking for. But unfortunately I cannot get it to work. (Tools wont compile in some versions, other versions crash, never really saw it work. Different Computer (Ubuntu 10.04 x64) shows other bugs)
Is there a tracing solution that is capable of visualizing the behavior of a pthreaded program on Linux, that is actually known to work?
Valgrind's Tool Suite [ Linux and OS/X ]
I've used Memcheck and it works as advertised. I haven't used the visualization tools yet however. Not sure if the output of Helgrind can be adapted for viewing with kCachegrind.
The Valgrind distribution includes four [sic] useful debugging and profiling tools:
Memcheck detects memory-management problems, and is aimed primarily at C and C++ programs. When a program is run under Memcheck's supervision, all reads and writes of memory are checked, and calls to malloc/new/free/delete are intercepted. As a result, Memcheck can detect if your program:
Accesses memory it shouldn't ...
Uses uninitialised values in dangerous ways.
Leaks memory.
Does bad frees of heap blocks (double frees, mismatched frees).
Passes overlapping source and destination memory blocks to memcpy() and related functions.
Memcheck reports these errors as soon as they occur, giving the source line number at which it occurred...
Cachegrind is a cache profiler. It performs detailed simulation of the I1, D1 and L2 caches in your CPU and so can accurately pinpoint the sources of cache misses in your code...
Callgrind, by Josef Weidendorfer, is an extension to Cachegrind. It provides all the information that Cachegrind does, plus extra information about callgraphs. It was folded into the main Valgrind distribution in version 3.2.0. Available separately is an amazing visualisation tool, KCachegrind, which gives a much better overview of the data that Callgrind collects; it can also be used to visualise Cachegrind's output.
Massif is a heap profiler. It performs detailed heap profiling by taking regular snapshots of a program's heap. It produces a graph showing heap usage over time, including information about which parts of the program are responsible for the most memory allocations...
Helgrind is a thread debugger which finds data races in multithreaded programs. It looks for memory locations which are accessed by more than one (POSIX p-)thread, but for which no consistently used (pthread_mutex_) lock can be found. Such locations are indicative of missing synchronisation between threads, and could cause hard-to-find timing-dependent problems. It is useful for any program that uses pthreads. It is a somewhat experimental tool, so your feedback is especially welcome here.
check this
http://lttng.org/ (Linux Trace Toolkit)
HTH
DIVINE can draw a graph of the state space and check for violated assertions.
Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 3 years ago.
Improve this question
Writing emulators has always fascinated me. Now I want to write an emulator for an IBM PC and run MS-DOS on it (I've got the floppy image files).
I have good experience in C++ and C and basic knowledge of assembler and the architecture of a CPU. I also know that there are thousands of emulators out there doing exactly what I want to do, but I'd be doing this for pure joy only.
How much work do I have to expect? (If my goal is to boot DOS and create a text file with it, all emulated)
What CPU should I emulate ? Where can I find documentation on how the machine code is organized and which opcodes mean what, so I can unpack and execute them correctly with my emulator?
Does MS-DOS still run on the newest generations of processors? Would it theoretically be able to natively run on a 64-bit AMD Phenom 2 processor w/ a modern mainboard, HDD, RAM, etc.?
What else, besides emulating the CPU, could be an important factor (in terms of difficulty)? I would only aim for outputting / inputting text to the system via the host system's console, no sound or other more advanced IO etc.
Have you written an emulator yet? What was your first one for? How hard was it? Do you have any special tips for me?
Thanks in advance
To know what is required from your emulator to run DOS, I think the best place would be to turn to the FreeDOS project that has reimplemented a DOS clone. By studying the source, you should be able to come up with a list of requirements.
Concerning the opcode, you can consult X86 Opcode and Instruction Reference, or the Intel documentation. You should also consider using the recent processor capabilities for virtualization.
DOS should still be able to boot a modern PC, but would probably be unable to use most of the hardware (due to lack of drivers, or to inherent limitation of the "OS").
If you want to emulate completely a PC to be able to run MS-DOS (or a clone), I think you'll have to:
decode and interpret opcode
emulate memory controller
emulate BIOS and VGA BIOS
implement required BIOS syscall
Disclaimer: I didn't write an emulator.
Since MSDOS is pure 16 bit code it can not run on a 64 bit processor natively.