I have been thinkining about buying a new computer.
It is possible to buy a 64 bit CPU box for a reasonable price these days.
(Why would you need a 64 bit computer you ask?, for the same reason people buy SUVs in a country where 99% of the roads are flat and paved. It's a testosterone thing, you know).
My question to the public is: How different is RCE in these new CPU?
Any experiences?

your experiences will first.
buy it, if it has 32bit mode (I don't know)

The low level strucutre of IA64 programs are completely different from programs on IA32. The IA64 programs can be explicitly parallelized by the compiler at build time (this is normally done at runtime by the super scalar IA32 processors), and thus the programs consist of "slots" in which you can fill in a different number of instructions of different types (using different parts of the processor) in each slot. Because of this pre-parallellization, I would guess that the code will be harder to follow "by hand" in most cases.

Anyway, all old programs and operating systems will still run in 32 bit mode on the processor, which should be identical to old processors (but on these low levels you can of course never really know if there are some small details that necessitate some smaller updates of at least the ring 0 debuggers for them to work correctly), but it should hopefully work without any bigger problems anyway.

That's true for IA-64 which uses an EPIC instruction set (Explicit Parallell Instruction C... something .. Not really made to directly program in assembler.. the compiler is responsible for scheduling the instructions, instead of the CPU.. the idea was that this made the circuitry simpler.. but I believe it didn't really work out and the 2nd generation is already smarter.. but don't take my word for it

The original poster didn't mention what 64-bit processor he was aiming for, but I guess he wanted an Athlon64 box. An Athlon64 is compatible with IA32, so no nasty emulation hacks as on IA-64. It can run in pure 64 bit mode or a mixed 32/64 bit mode. In pure 64 bit mode, it is still very similar to IA-32 (same instructions, but 64 bit registers and a bigger register file.. ie 16 General purpose registers). Anyway it's still a CISC instruction set.

Or.. maybe he wanted to buy a Mac with a 64-bit PowerPC processor.. In which case it would be a RISC instruction set.

(guess we got all the major sets now

"the compiler is responsible for scheduling the instructions, instead of the CPU.. the idea was that this made the circuitry simpler"

well i realy don't know why the world hasn't advanced to the next gen of 64bit cpu ... all we need to do is compile our application in new compiler so it will changed all of it to 64bit way....

so the realy Q is :

how does the SoftWare companies will convert their apps to 64bit ?
i.e : PhotoShop / Maya / 3D.Studio Max etc..

???

That's only true if the code was written cleanly, without assumptions of how big an int or any other variable is..

Also.. some of the examples you gave, probably use assembler to get more performance out of their code.. so using a 64 bit compiler won't help there as you need to rewrite the asm code.


Another reason: 64 bit is not always faster (in many cases it's slower, as you need to fetch more data.. ie 64 bit = 2x 32 bit.. so you need to get twice as much data from your memory).
The only reason you need 64 bit, is if 4Gb isn't enough.. until recently that meant only big databases needed 64 bit.

The Athlon64 offsets the performance decrease, by having more general purpose registers, so that you need to hit memory less frequently.


Unless your current PC needs >4Gb memory, I'd stick with a 32 bit CPU .. that is.. if you don't account for the testosterone
(NOTE: IA-32 can also address more than 4Gb memory, using Page Address Extensions - PAE - but that is scaringly similar to the DOS days with memory banks )

This is easy to answer. They all use C or C++ for their development (naturally). Microsoft already released VC++ for IA64 so it's just a matter of recompiling and fix portability related bugs.

// CyberHeg

Isn't the real issue that there needs to be a sufficient base of 64 bit compliant software to actually use to justify the extra cost of such systems? It's kind of like putting a supercharged engine in a golf cart and then putting aroung the course, wondering when and where you will find a use for all that potential speed.

Regards,

If it wasn't for the testosterone issue, that would be the case, yes.

I'm not familiar with that "testosterone program." Memory fades, the lights dim. Where can I get a copy for my machine?

Regards,

Howdy,

64 is nice but, like bus speed, it's just for talking about.
The cost is sort of scary.

I would hold off until you find that your regular app's are ready
to utilize the increased speed. Of course you will need new ram and
a 150,000 RPM hard disk and a bus speed of about 9.3 gig.
OK, I exagerate but, you know what I mean.

Woodmann

Why not mess around with over clocking, just get
some app's to monitor and go for it.

Hem! Let me upgrade my Question..

I already know, that AMD have 32bit mode, but Question is:
this 32bit mode for 32bit program is accesible directly in 64bit OS?
Or user must restart PC & load 32bit OS?

Hello naides,

Just read the below interesting thread on asm forum. It discusses how asm will be on 64 bit cpu box. Though its not part of your question but still interesting info provided.

hxxp://board.win32asmcommunity.net/showthread.php?threadid=16630

Regards, Sope.

The Athlon64 has a mixed 32/64 mode. So a 64-bit OS can run 32-bit programs without emulation.

well, thanks for info.

naides, how about MACos reversing=)