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Subject: Re: arrays & pointers

Re: arrays & pointers

From: Dave Hooper <dave_at_beermex.com>
Date: 2005-01-03

Wow. What compiler are you using? This looks like an easy compiler
optimisation to me, so I'd be amazed that you'd need to manually do
something like this (i.e. put the pointer into a local variable and do
accesses through that rather than dereference the array more than once). I
mean, seriously, this is what compilers are *for*.

----- Original Message -----
From: "BlueChip" <cs_bluechip@webtribe.net>
To: "Rockbox development" <rockbox@cool.haxx.se>
Sent: Monday, January 03, 2005 8:34 PM
Subject: arrays & pointers

> Just saw this go in...
>
> Log Message:
> using a pointer instead of array dereferencing saves ~250 bytes
>
> From my work on the card games library ...I discovered that arrays are
> probably THE most expensive thing for our compiler. If you are going to
> reference an element in array even just twice, it is memory efficient to
> create a pointer to that element and use the pointer instead.
>
> Given the _excessive_ efficiency of it, I guess it is also faster as well!
>
> If you're going to access the pointer several times, you might even like
> to stick a "register" in front of it for extra speed :)
>
> BC
>
> _______________________________________________
> http://cool.haxx.se/mailman/listinfo/rockbox
>

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Received on Mon Jan 3 23:54:29 2005


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