RE: reduction operators (mantix 938)

I'm not sure what version of the standard Sri was looking at.

The bit-wise binary operators are &, |, ^, ^~, ~^. These are binary
operators, i.e., they take 2 operands.

There is 1 unary bit-wise operator: ~ (bit-wise negation, 1's
complement).

The unary reduction operators are: ^, ^~, ~^, &, ~&, |, ~|. These take
only one operator and the result is only one bit. Although some look the
same as binary bit-wise operators, they are different ones. You know
from context which is being used, by whether it is used as a binary or
unary operator.

In Verilog, you can use all of these on integers, but not on real
numbers.

Do you really need an analog version?

Shalom
 

> -----Original Message-----
> From: owner-verilog-ams@eda.org [mailto:owner-verilog-
> ams@eda.org] On Behalf Of edaorg@v-ms.com
> Sent: Monday, January 30, 2006 11:16 AM
> To: verilog-ams@eda.org
> Subject: [Fwd] reduction operators (mantix 938)
> 
> 
> From: Jonathan David <jb_david@yahoo.com>
> 
> Hm.. maybe I should indicate a willingness to do more
> than LURK on this list and help with the 2.3 draft,
> even though I won't get Scintera to join Acellera.
> 
> ---Sri's last comments were:
> I thought they were already present in the language as
> bit wise operators - In chapter 4, Table 4-1 we have
> operators such as ~& and ~| which is bitwise and/or
> operators. Probably we dont have bitwise xnor.
> 
> Is the same thing being referred here or something
> else in digital LRM that we dont have?
> 
> Need to have the full array of operators in digital.
> 
> Some might have some restrictions - real?
> -------------------------------------------
> what I discovered (and mentioned to Martin a while
> back) was that on the digital side for
> reg [1:0] a;
> 
> you get the following truth table for (&a)
> a  &a  |a  ^a
> 00  0   0   0
> 01  0   1   1
> 10  0   1   1
> 11  1   1   0
> 
> this is the essence of a reduction operator as opposed
> to a bitwise operator..
> the single (but multibit) argument is reduced to a
> single bit..
> 
> like their bitwise version, in the analog context the
> domain should probably be limited to integers..
> 
> Jonathan
> 
> 
> 
> 
> 
> 
> ----- End Included Message -----