




Cortex M


Source: The Korea Herald

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RE: 128-bit?
By Shadowself on 11/22/2013 1:18:05 PM , Rating: 2
There certainly are advantages beyond the addressable space for going to a true 64-bit processor as you point out.

But what is really a 64-bit processor? For that matter, what is a 32 bit processor? To see how confusing the naming can be you only need to look back at Motorola's 68000 series processors, back when processors were actually chip sets and not monolithic chips. The 68000 chipset was called a 32 bit processor, but in its first implementation it did 32 bit integer math internally, had a 16 bit data bus, had a 24 bit address buss and interfaced to a math co-processor chip that did 32 bit single precision, 64 bit double precision and 80 bit extended precision math. So was the 68000 chipset a 16 bit, a 24 bit, a 32 bit, a 64 bit or an 80 bit chipset?

People often like to focus on the address space -- hmmm... the original POWER chipset was considered a 32 bit chipset. However, IIRC it had a 48 bit address space. So was it a 32 bit chipset or a 48 bit chipset?

Right after Apple announced the "64 bit" A7 chip, Samsung said that early next year they would be shipping a chip with "64 bit features", but what "features" are those? Just as an extreme example, if it has a 16 bit data path, a 32 bit address space and does 64 bit floating point can they say it has "64 bit features"?

Go back to the first desktop chips with vector processing capabilities. Most of those had either 128 or 256 bit vectors, but they were still called either 32 or 64 bit chips.

I wish the naming "conventions" were consistent, but unfortunately the naming of the "bitness" of chips has been run by marketing types since the late 70s and not hardware or software engineers.

The bottom line is that until the chips Samsung is discussing are taped out and the ground rules of that tape out are made public (they often are not) we have absolutely no idea what Samsung means by "64 bit" or "128 bit". Anyone who says otherwise is just blowing smoke. Until then it's 100% marketing hype.

RE: 128-bit?
By inighthawki on 11/22/2013 4:04:46 PM , Rating: 2
The bittedness of a CPU is commonly associated with the native word size of the processor, which is also typically the same size as the main registers.

