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ARM Goes 64-Bit With Its New ARMv8 Chip Architecture
angry tapir writes "In less than a decade, a microprocessor core could be no bigger than a red blood cell, the CTO of ARM has predicted. ARM has already helped develop a prototype, implantable device for monitoring eye-pressure in glaucoma patients that measures just 1 cubic millimeter, CTO Mike Muller said at ARM's TechCon conference. At the conference the company also introduced its first 64-bit chip. The ARMv8 adds 64-bit addressing capabilities, an improvement over the current ARMv7-A architecture, which is capable of up to 40-bit addressing. The architecture puts ARM into more direct competition with Intel and its 64-bit Xeon processors."
Here's a better description of the new Architecture:
ARMv8 Architecture PDF
> "The architecture puts ARM into more direct competition with Intel and its 64-bit Xeon processors."
Who is writing and editing this BS? It is not in any way putting ARM in competition with Xeon CPUs. It is becoming a serious contender for low end CPUs: Atom, Pentium, Athlon, and it is getting more interesting for streaming and massive threading applications (like the SPARC T).
Is 64-bit really needed in mobile devices? It increases the number of wires and data transfer, which means less power efficiency.
It is worth pointing out that current x86-64 implementations are limited to addressing "only" 48 bits so it's not like that ARM was way beyond the curve with their 40 bit address space (that's 1 TB).
Real life is overrated.
- ARM press release
"National Security is the chief cause of national insecurity." - Celine's First Law
The architecture puts ARM into more direct competition with Intel and its 64-bit Xeon processors.
Gee, what about AMD and the AMD64 architecture that they developed? You know, the one that Intel eventually had to adopt (license?) when their 64-bit Itanium didn't quite live up to their expectations of being the next architecture that everyone moved to?
Oh, and ARM Holdings don't make chips. They design architectures and implementations that others license and put into actual chips. The summary wasn't so clear on that, and it's a point that lots of people often overlook.
Maybe I've just got a certain prejudice, but I don't see any direct comparison, let alone competition, between ARM processors and Xeon processors, no matter how wide their addressing is. ARM processors run some really sophistocated stuff ... in my smartphone. A Xeon processor allows my CAD workstation to handle 3D models with thousands of components, or run an ANSYS simulation that solves the equivalent of 10 million simultaneous equations.
At least "god damn x86" has a standardized boot process, be it BIOS or EFI. Let me know when more than one make and model of ARM computer can boot from the same memory card.
Why both going through 128 and 256 bit?
Just make the leap up to 1024 bit! It's inevitable eventually...
"That's the way to do it" - Punch
I would absolutely love to have CPUs embedded in my genitals. That way I could mine some Bitcoins even while taking a piss.
And as an added bonus the heat given off will pretty much ensure you don't have kids.
Monstar L
"I got me 64 gigabytes of RAM;
I don't feed trolls and I don't ream SPAM;"
-- Weird Al
Hmm, will have to change the refrain, it's not all about the Pentiums anymore, baby.
The Commodore 64 CPU (Mos 6510, a variant of the well-known 6502) was not a 16-bit CPU. It had 16-bit addressing, but was still an 8-bit CPU.
Is this a real 64-bit CPU, or just a 32-bit CPU with 64-bit addressing?
Doubling the size of the registers requires a LOT of work internally to a CPU and is not done lightly - thats why 32bit held on for so long in the consumer world. Also there are 2 (main) types of bit measurement - address bus size and data bus size. An increase to 128 or more for the data bus size may be useful for some applications and that has already been done in some areas - eg graphics cards - but increasing the address bus size to 128 bits will bring no conceivable benefits as we're still a long way off being able to manufacture memory chips that can even approach the 2^64 bit size set by 64 bit never mind 2^128.
There are already several comanies working on multi-core ARM chips for servers, because they believe that will be the most power-efficient way to handle big workloads. Here is one product announcement from the day after ARM 64 was announced:
SANTA CLARA, Calif. – Applied Micro Circuits Corp. fired a shot across the bow of Intel, demonstrating the first 64-bit ARM server processor here. The X-Gene chip is the first of an array of competitors that will attack Intel's multi-billion dollar server franchise with cheaper, lower power ARM SoCs.
AMCC's X-Gene packs multiple 3 GHz cores complaint with the ARM 64-bit V8 architecture announced today at ARM Tech Con. The cores are quad-issue, out-of-order superscalar designs. The chip also sports Ethernet MACs, PCI Express and Serial ATA linked on an 80 GByte/second fabric.
The company showed a working version in an FPGA emulation it will ship in January. Silicon will sample in the second half of 2012.
Note that register size and address size need not be the same. There were many processors out there with 16-bit memory addresses but only 8-bit registers and data bus. Likewise most 16-bit systems had some mechanism for accessing more than 2^16 memory addresses. Even 32-bit systems often had mechanisms for accessing more than 2^32 memory address though they were little used.
OTOH 64-bit CPUs often don't bother with support for full 64-bit addresses (though they are often designed so they can be allowed in future without changing userland code) because people simply don't have anywhere near that much memory.
I don't think there is much point increasing the size of integer data words beyond 64-bit. Most apps simply don't need numbers that big.
note: i'm known as plugwash most places but i screwd up registering that here somehow in the past and now can't register
These chips need a bunch of address space to access peripherals. When you are at 2GB it starts to get a little tight, depending on how big the windows are for your I/O space (64M per peripheral is not an uncommon size, even if it is just for the registers for a serial or I2C port). Once you get 4GB then you really are stuck and have to use extended addressing and play highmem games in the kernel.
“Common sense is not so common.” — Voltaire
Which changes nothing. Please allow me to rephrase: At least one major computer maker invented a widely adopted standardized boot process for "god damn x86". This hasn't yet happened for ARM.
ARM still has a serious weakness versus x86 and x86-64: it uses a weak memory consistency model. For single-threaded applications that's no issue, but the overwhelming majority of programmers cannot effectively utilize the potential compute power in a multicore environment. In x86-64 it's quite easy because there's very limited reordering (with the exception of some SSE operations) and it is possible to reason about it efficiently after some experience. Sure, you can rely on locking for 100% of your synchronization, but you'll kill performance.
"Politicians and diapers must be changed often, and for the same reason."
ARM is scaling up, while x86 is scaling down to get to this future "computing nirvana" where mobile meets desktop. I think x86, through AMD, is going to reach the computer/smartphone conversion line before ARM will. But the problem is the timeframe. Five years for ARM? AMD is at 2.1W for their tablet brazos chip with directX 11 and 64bit today. Meanwhile, Intel is just pissing around with Atom; their nextgen Cedartrail was thrown together with PowerVR graphics, can't even pass Win7 certification, and can only to 32bit DirectX 9.
Most apps have integers that need less than 8 bits. I don't think registers need to be 128 bits, but a wider data bus would be great if you could load/store 2 or 4 registers at a time. I always thought that the larger registers get the more bits are wasted when you only need small numbers. If you could store say 2 x 16 and a 32 in one register and operate on them individually, It would save a lot of room. Can any modern architectures do this or is it not worth it?
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