Re: [BLACKBOX] ARRAY as CONSTANT

From: [at]} <CFB>
Date: Wed, 13 Feb 2008 16:26:10 +1030

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> -----Original Message-----
> From: BlackBox [mailto:BLACKBOX{([at]})nowhere.xy
> Oleg N. Cher
> Sent: Wednesday, 13 February 2008 2:58 PM
> To: BLACKBOX{([at]})nowhere.xy
> Subject: Re: [BLACKBOX] ARRAY as CONSTANT
>
>
> What we will have? 60 Kb of machine code produces 10 Kb of data.
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

If your data are integers then the alternative is 40Kb of data not 10Kb of
data. Otherwise your original Delphi code example should have been written
as:

  CONST
    a: PACKED ARRAY [0..4] OF BYTE = (1, 2, 3, 4, 5);

instead of:

  CONST
    a: ARRAY [0..4] OF INTEGER = (1, 2, 3, 4, 5);

Now if that is the case, every time you try to access an element of data it
is going to require more, and inefficient code, as 8-bit byte accesses are
more inefficient than 32-bit integer accesses. (On Win32 that is)

Six of one - half a dozen of the other - what you might save in one area
costs you in another. It is not quite as simple as it may seem at first
sight ....

Chris Burrows
CFB Software
http://www.cfbsoftware.com/cp

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Received on Wed Feb 13 2008 - 06:56:10 UTC