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From: Keean Schupke <keean.schupke@googlemail.com>
Newsgroups: comp.lang.ada
Subject: Re: Efficient Sequential Access to Arrays
Date: Thu, 19 Jul 2012 12:58:33 -0700 (PDT)
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Date: 2012-07-19T12:58:33-07:00
List-Id: <comp.lang.ada>

On Thursday, 19 July 2012 12:18:11 UTC+1, Georg Bauhaus  wrote:
> On 19.07.12 12:41, Keean Schupke wrote:
> &gt; What is more of a problem is that the node structure is 32 bytes lon=
g, so two nodes fit in a 64bit cache line, and the index operation is shift=
 left by 5. Adding the extra Index word will probably slow things down sign=
ificantly, unless we can save some space elsewhere in the structure.
> &gt;=20
> &gt; I may be able to replace one Integer with a Short_Int, and use a Sho=
rt_Int for the index. I think this could be worth trying.
>=20
> I&#39;ll assume it is a 32 bit program already? (As GNAT uses 32 bis
> for addresses then, not 64.)

Its a 64bit platform, so the pointers are 64bits but the integers 32bit. I =
think what I was thinking is with the indexed version, I may be able to shr=
ink the whole data structure from 32bytes to 16bytes, and that would fit 4 =
elements in a cache line instead of two. Maybe this would make up for the s=
lower indexed addressing. It will try and post my results.

Cheers,
Keean.