Re: How many times must Apple make such DRASTIC architecture changes?

[Paul Schlyter <pausch@NOSPAMsaaf.se>]

In article <bhy*JGXQq@news.chiark.greenend.org.uk>, 
timc@chiark.greenend.org.uk says...
>In article <11am8lu3aj5i71a@corp.supernews.com>,
>G.T. <getnews1@dslextreme.com> wrote:
>>> Absolutely.  Integer performance is all that matters for the vast
>>> majority of desktop consumer applications (games might be an exception,
>>> these days).
>>>
>>
>>Aren't sound and video exceptions, too?
>
>Not as I understand it; 2D image processing and video (and sound) are
>integer operations.  In the case of e.g. TIFF, you use integer values to
>represent the levels of red, green and blue.  It's all integer numeric
>data.

...however if you want to manipulate the image somehow, e.g. increasing
the blue intensity by a specific percentage, it's much easier if you have
floating-point operations available.

>The same's true of digital sound; you use integer values to
>represent the intensity.
>
>The Altivec, heavily used for image processing, is an integer vector
>unit.
>
>And even in floating point applications, doing an approximation using
>integer maths is often good enough, by and large, and considerably
>faster.

...on hardware without any floating-point processor, that is.  On PC's
that means up to the 386, where the floating-point processor was an optional 
extra, and absent from most systems.

>Any of you who have used 'Fractint' on a PC will have seen that
>in action; generating these fractals is in theory a pure floating point
>problem, but those guys developed a blisteringly fast integer
>approximation which works well at low magnifications.

Fractint was written when most PC's had a 386 CPU.  True, you could add an
optnional 387 floating-point unit if you wanted, but most people didn't.

Starting with the 486 the floating-point unit was built in.

And on today's PC's, writing FractInt would be pointless, since a FractFloat
would most likely be faster.... 

>Tim


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