

ARMv7a architecture gets 40-bit addressing and virtualization support - wmf
http://www.eetimes.com/electronics-news/4206387/ARM7-40bit-virtualization

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dman
Heres linus's take on it - "Paul (no@thanks.com) on 8/24/10 wrote: > >'ARM
Ltd. announced extensions for virtualization and 40-bit >addressing to the
ARMv7a architecture, two of the key new >aspects of ARM's upcoming Eagle
core.' Oh gods. Please don't say that it's another PAE mess. It's a major
pain, and having to specially map all the physical pages that you can't fit
directly in the virtual address space leads to some nasty issues.

I hope they have a plan to move it towards a real 64-bit architecture. But it
sounds like ARM is doing the whole "do all the mistakes x86 ever did" thing.

And the funny thing is, ARM people think that x86 is the ugly architecture.
But with x86 cleaning its stuff up, and ARM apparently convinced it needs to
do all the mistakes x86 did, we'll soon see ARM as the real cesspool.

    
    
                          Linus"
    

from
[http://realworldtech.com/forums/index.cfm?action=detail&...](http://realworldtech.com/forums/index.cfm?action=detail&id=112310&threadid=112309&roomid=2)

~~~
acqq
Still there's a good reason not to use 64 bits: interconnections, transistor
count, die size. You can't have a CPU that sips milliwats of power and make an
architecture of a 50 Watts beast.

~~~
hga
But to the extent they want to compete with Intel and AMD in server space
they're going to have to go all in to a full 64 bit design. What is the Eagle
design for? Is there any other target market that needs a PAE half-measure
like this?

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bugsy
Thank goodness some CPU designers have some common sense. There is no
advantage whatsoever to 64 bit addressing. You are just pushing a bunch of
zeros around forever. That's not to say 32 bit is enough. 40 bit shows the
designers have some sense and aren't just pandering to ignorant masses who
think that because 2*32 = 64 that means something.

~~~
dumael
Eh, not if involves using the equivalent of PAE. 40bit addressing in that
requires applications to utilize a window to use memory. And pointers get
invalidated when the window is moved. Hurrah for CPU designers shoving immense
workloads onto the software devs, especially application programmers.

