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Date: Sun, 30 Oct 2005 22:46:20 +0100
From: Gautier Write-only <gautier@fakeaddress.nil>
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Subject: Re: Simulation of fixed point in c WITH DIFFERENT BIT-WIDTH
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Date: 2005-10-30T22:46:20+01:00
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mnamky wrote:

> Hi all;
> 
> Consider the following exaple
> y = x * b'
> 
> where x is 12-bit wordlength and 11-bit fraction
> and b is 16-bit wordlength and 14-bit fraction
> 
> simulation of this code is rather easy im Matlab but how could we do a
> full analysis of this code in C with a good precision?
> 
> Thank you

It is also easy in Ada - something like...

procedure Fixed_12 is
  type F1 is delta 2.0**(-11) range -1.0 .. 1.0;
  type F2 is delta 2.0**(-14) range -2.0 .. 2.0;
  x  : F1;
  y,b: F2;
begin
  x:= 0.12345;
  b:= 1.23456;
  y:= x * b;
end;

The precision is guaranteed - better than good...

But you want to do this in C ?! By Jove!
Fortunately, your subconscient suggested you the right newsgroup.

BTW, something is wrong, either with your Shift key, or with your Caps Lock key - see the title.
I can only sympathize, after having a similar problem: some beer had found unexpectedly its way into my keyboard.
______________________________________________________________ 
Gautier     --     http://www.mysunrise.ch/users/gdm/index.htm 
Ada programming -- http://www.mysunrise.ch/users/gdm/gsoft.htm 
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