Assuming you have a 64 bit capable processor running a 32 bit operating system. Would it be possible to run some 64 bit assembly instructions in a 32 bit program? Can't see why not if you have a 64 bit capable processor, but there are so many stingy technical issues in computing, especially the operating system.
NOTE I am not talking about running a 64 bit program on a 32 bit os, just using 64 bit assembly instructions embedded in a 32 bit program.
The thing you would most need to know on this is to make sure you make your processor mode transitions correctly. You need to do some basic work to transition from 32 bit mode into 64 bit mode (also called long mode). The biggest issue would be making sure you set up the descriptor table correctly. Some more info is here:
http://www.codeproject.com/Articles/45788/The-Real-Protected-Long-mode-assembly-tutorial-for
Hope this helps.
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Actually I want to link 64 bit library to my 32 bit application.
I want to use a library which works faster under 64 bits under some circumstances. But i have to link that library to my 32 bit application . Is it possible or not ??
In a word, no. The only way to get compiled 64bit code talking to compiled 32bit code is via some form of IPC (e.g. pipe, named pipe, or network connection). That may well introduce performance bottlenecks of its own, so probably isn't worth the bother.
It is not easy as #robthebloke mentioned. But NVIDIA RTX Remix Runtime does it somehow, making older 32bit games running on 64-bit vulkan driver (bypassing 2-4GB virtual memory limit).
I have created my OpenCL code in a dll which I am loading in my application.
Now for my 64 bit application it is crashing for the call getPlatformIds().
However Dependency Walker is showing everything is 64 bit and no errors.
But the same application with 32 bit is working perfectly.
Is it possible that my GPU cannot perform 64 bit tasks?
But C:/Windows/System32/OpenCL.dll is also 64 bit so probably my hardware is ok?
How do I determine what might be causing the crash?
Husshhhh....
The issue is finally resolved...:)
Looks like there is some linker problem with the MinGW 64 bit compiler.
The solution is to link the libopencl.a file instead of OpenCL.dll for building 64 bit applications.
While building for 32 bit applications does not require this i.e. you can link with OpenCL.dll.
Now only if somebody can fix this issue which has been open for past 4 years!
I'm a beginner programmer in my first year of Computer Science.
I'm curious about the 32 bit and 64 bit systems, and how it affects developing software.
When I download software I need to choose between the two, while other software only has a 32 bit version.
Are there different ways of programming for a 64 bit system?
Is it compiled in the same way?
What are the main benefits of a separate 64 bit app?
Cheers
Are there different ways of programming for a 64 bit system?
Yes and no. No, in the sense that most of the time you should be able to write platform-independent code, even if you are coding in a language like C. Yes, in the sense that having knowledge of the underlying architecture (not just the word size!) helps to speed up critical parts of your program. For instance, you may be able to use special instructions available.
Is it compiled in the same way?
Again, yes and no. Compilers for systems languages work in similar ways for all architectures, but of course, the details differ a bit. For instance, the compiler will use knowledge about your architecture to generate as efficient code as possible for it, but also has to take care of differences between architectures and other details, like calling conventions.
What are the main benefits of a separate 64 bit app?
I assume you are asking about the usual desktop CPUs, i.e. x86 architecture, but note that there are other architectures with word sizes ranging from 8-bit to 128-bit. Typically, people would compile a program targeting a single architecture (i.e. for a given machine), and that's about it.
However, x86 is a bit special, in that the CPU can operate in different modes, each with a different word size: 16-bit, 32-bit and 64-bit (among other differences). Effectively, they implement several ISAs (Instruction Set Architectures) in a single CPU.
This was done to preserve backwards compatibility, and it is key to their commercial success. Consider that, when people bought the first 64-bit capable CPUs, it was most likely that they were still using 32-bit operating systems and software, so they really needed the compatibility. The other options are emulating it (poor performance) or making sure all the popular customer software has been ported (hard to achieve in ecosystems like Windows with many independent, proprietary vendors).
There are several benefits of 64-bit x86 over 32-bit x86: more addressable memory, more integer registers, twice the XMM registers, a better calling convention, guaranteed SSE2... The only downside is using 64-bit pointers, which implies more memory and cache usage. In practice, many programs can expect to be slightly faster in x64 (e.g. 10%), but pointer-heavy programs may even see a decrease in performance.
Generally speaking the main benefit of 64 bit application is that it has access to more memory. Having 32 bit pointer you can access only 4GB of memory.
Most modern compilers have option to compile either 32 bit or 64 bit code.
32/64 coding is the same unless you are dealing with huge in-memory objects, where you would need to use 64 bit specifically.
An interesting fact/example is that Unix time is stored as a single number. It is calculated as a number of seconds passed from January 1st 1970. This number will soon reach 32-bit size, so eventually we will have to upgrade all of our systems to 64-bit so they can hold such a large number.
I am creating a quite simple application which reads and display text files and search through them.
I am asking myself if there is any interest for me to propose 32 and 64 bits version to the user.
Is the difference only in having access to more memory heap size with the 64 bit version or is there any other interest ?
Will a 32 bit compiled program work on a 64 bits JVM (I assume yes)
The only differences between 32-bit and 64-bit builds of any program are the sizes of machine words, the amount of addressable memory, and the Operating System ABI in use. With Java, the language specification means that the differences in machine word size and OS ABI should not matter at all unless you're using native code as well. (Native code must be built to be the same as the word-size of the JVM that will load it; you can't mix 32-bit and 64-bit builds in the same process without very exotic coding indeed, and you shouldn't be doing that with Java about.)
The only times that have swung it for me is when there have been native libraries involved that have pushed it one way or the other. If you're just in Java land then realistically, unless you need >4GB of heap size, there's very little difference.
EDIT: The differences include things like it uses slightly more memory than 32 bit, significantly more if you're using a version before 6u23 and aren't using -XX:+UseCompressedOops. There may also be a slight performance difference between the two, but again nothing huge.
I'm not a programmer, but learning some programming concepts.
My question is, on 32 and 64 bit systems, the HAL layer will be different as they are two different platform, how does the driver interact with HAL layer and in turn with CPU?
If we take an example of LAN driver, can anybody explain in high level what exactly happens in two different platform that is 32 and 64?
Any pointer will be great help...
Thanks,
Pramod.
You re-compile the drivers for each platform. The APIs are the same but the code generated by the compiler will be different.