On Wed, 2009-10-21 at 11:09 +0530, Siddu wrote: > > > On Wed, Oct 21, 2009 at 8:32 AM, Rick Brown <rick.brown.3@xxxxxxxxx> > wrote: > Hi, > > Firstly, I'm trying to understand what exactly characterizes a > procesor or an operating system as 32bit / 64 bit. I've read > that it > means the "native word size" of a machine. But what exactly is > that? > Register size? Address bus size? Anything else? > > > When they say its 32/64 bit machine its the capability of the system > or processor to process so many bits at once ! Additionally, the virtual memory address is 64 bit. Also the main difference is with sizeof(long int) and sizeof(void *) on both archs. > > > > Secondly, I'm trying to understand what exactly does a > sizeof(int) > depend on when we say it is "platform specific". Is it > dependent of > compiler being 32bit / 64 bit? Or the OS being 32bit / 64 bit? > Or the > processor being 32 / 64 bit? > > its dependent on processor being 32/64 bit > > > Lastly, How are "sizes" of compiler / OS / processor inter > related? > Here is my understanding. A 32 bit processor can only be > running a 32 > bit OS. > > No ... 32 bit OS can run anything <= 32 bit > > A 64 bit processor may run a 32 or a 64 bit OS. > > yes thats right ! > > > A 32 bit > compiler genrates code only to be run on a 32 bit OS; ditto > for 64 > bit. > > Not sure about this let others have their say ! > > Is this right? It is possible to use the -m32 and -m64 flags with gcc for generating 32/64 bit compatible code. -- To unsubscribe from this list: send the line "unsubscribe linux-newbie" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.linux-learn.org/faqs
