Re: [myhdl-list] Slicing an unsigned intbv to a signed one

[Christopher F. <cf...@uc...>]

Yes I will send the patch when I get home.  I believe you are correct 
my quick implementation probably only covers the power of 2 cases. 
 For the non-power of 2 cases, I think it still works cause you have 
to have a power of 2 (can't have fraction of a bit) the msb of the 
least number of bits (which is the _nrbits) is still the sign bit? 
 Just thinking out loud.

Thanks

On Thu, 12 Jun 2008 20:45:12 +0200
  Jan Decaluwe <ja...@ja...> wrote:
> Christopher L. Felton wrote:
> 
>> Below is the output example for a small change that I made to the 
>>bit 
>> vector class
>>>>> from myhdl import *
>>>>> x = intbv(0, min=-8, max=8)
>>>>> x[3] = 1
>>>>> x
>> intbv(-8L)
>>>>> x[3] = 0
>>>>> x
>> intbv(0L)
>> 
>> To implement the above I simply modified __setitems__ and used the 
>>_min 
>> and _nrbits values determine what type of number is being 
>>represented. 
>>  If the number is signed multiply the value by -1 if the msb is 
>>being 
>> modified.  
> 
> Could you show your patch (just a diff)? I don't see how this
> would be correct for non-powers of 2.
> 
> Jan
> 
> -- 
> Jan Decaluwe - Resources bvba - http://www.jandecaluwe.com
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