[erlang-questions] 16-bit Erlang: crazy? Or just stupid?

[Giovanni Giorgi]

Agree with Jesper.
 Lowering the data size could bring some benefit if you are able to "pack" data in a 64bit address, but it will bring even worst performance...

x86 modern architecture is built with more efficient 64bit-opcode. 
Simply put the chip are "reversed" to work better with a 32,64bit address opcode and end up eating more cycle if you force them to push 16bit op-code.
(they must "shift out", the unwanted bits).
Also:
+ Arduino ATM-Mega chip is a 8bit chip which provide easily 32bit adressing without problem.
+I have a RasberryPI ARM 4x-core for 45€ with 32bit in it.... 
...there are not any more embedded 16bit chip nowedays...
Think twice before doing it.


On 07/ago/2015, at 11:35, Jesper Louis Andersen <jesper.louis.andersen@REDACTED> wrote:

> In principle, with enough work, this is possible, though in a modern world I think the 16 bit address space ends up being too small. The 32 bit address space is quite viable however, and that experiment has been done, see the halfword-emulator for Erlang.
> 
> The idea is to run Processes in a 32bit space, but keep ETS tables and other things in a 64 bit space. The end result is less memory pressure for processes, smaller pointers in many cases and so on.
> 
> I'm somewhat hesitant to say we would win much by having smaller data paths down to 16 bit. It doesn't look like this is the primary limitation of modern CPU architectures: power, memory bandwidth, and a tiny issue width is.
> 
> 
> On Thu, Aug 6, 2015 at 8:40 AM, Michael Turner <michael.eugene.turner@REDACTED> wrote:
> I screwed up the access settings in Google Docs. You should all be able to read it now. Sorry for the stupid, crazy service failure.
> 
> Regards,
> Michael Turner
> Executive Director
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> "Love does not consist in gazing at each other, but in looking outward together in the same direction." -- Antoine de Saint-Exupéry
> 
> On Wed, Aug 5, 2015 at 4:27 PM, Michael Turner <michael.eugene.turner@REDACTED> wrote:
> 
> Comments invited.
> 
> https://docs.google.com/document/d/10GfPfpqQKzV6Ws7MULPBue6VoAaZF-vGHTQ4UFAXtSw/edit
> 
> Regards,
> Michael Turner
> Executive Director
> Project Persephone
> K-1 bldg 3F
> 7-2-6 Nishishinjuku
> Shinjuku-ku Tokyo 160-0023
> Tel: +81 (3) 6890-1140
> Fax: +81 (3) 6890-1158
> Mobile: +81 (90) 5203-8682
> turner@REDACTED
> http://www.projectpersephone.org/
> 
> "Love does not consist in gazing at each other, but in looking outward together in the same direction." -- Antoine de Saint-Exupéry
> 
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--
[    [   [  Giovanni ``Daitan`` Giorgi ]   ]    ] 
jj@REDACTED

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