From: Jos De Laender <jos.de_laender@alcatel.be>
Subject: Re: Newbie question : types , representation
Date: 1999/08/25
Date: 1999-08-25T07:26:27+00:00 [thread overview]
Message-ID: <37C39B30.CEBEE0B5@alcatel.be> (raw)
In-Reply-To: Pine.BSF.4.10.9908242009410.3007-100000@shell5.ba.best.com
Thanks,
this was really very to the point for what concerns my problem !
I learned from it.
Some small comments furtheron between your text.
Best regards,
Jos
Brian Rogoff wrote:
> If you know that characters are the same size as your "byte" type, be it
> an Interfaces.Unsigned_8 or a System.Storage_Element then it should be OK
> to use Unchecked_Conversion if you're worried about the overhead of a
> conversion function, but I really can't imagine any overhead even from a
> safe type conversion if you turn checking off, which you really must do if
> you want to compare with C. I don't understand why you think there is some
> table lookup involved.
I think here I was partly wrong. The table lookup is needed for the original
algorithm where I got the problem (base64 decoding) , but it is equally needed
in C as in ADA. So forget indeed this one ...
>
>
> Part of the problem with C and Ada comparisons is that every C operation is
> unchecked, whereas in Ada everything is checked by default. You have to
> know enough about your Ada compiler to turn off those checks when doing
> the performance comparisons.
I realize this extremely well ! As I told you I do know VHDL quite well , and I
have to use always this same explanation to explain the 'C is faster crowd'
that when comparing the same functionality , including the checking , it isn't.
>
>
> -- Brian
Jos De Laender
next prev parent reply other threads:[~1999-08-25 0:00 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-08-22 0:00 Newbie question : types , representation Jos De Laender
1999-08-22 0:00 ` Martin Dowie
1999-08-22 0:00 ` Robert Dewar
1999-08-23 0:00 ` Wolfgang Jeltsch
1999-08-24 0:00 ` tmoran
1999-08-24 0:00 ` jdla
1999-08-24 0:00 ` Matthew Heaney
1999-08-24 0:00 ` Jos De Laender
1999-08-24 0:00 ` Brian Rogoff
1999-08-25 0:00 ` Jos De Laender [this message]
1999-08-22 0:00 ` Wilhelm Spickermann
1999-08-23 0:00 ` Simon Wright
1999-08-23 0:00 ` Martin C. Carlisle
[not found] ` <37C621F3.C6C0DC3A@acenet.com.au>
1999-08-27 0:00 ` tmoran
1999-08-27 0:00 ` Florian Weimer
1999-08-27 0:00 ` David C. Hoos, Sr.
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