gEDA: Unrolling sequential loops

[Ales Hvezda <ahvezda-at-NOSPAMseul_dot_org>]

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Dear GEDA developers,

first of all, thanks for your great tools.

I am wondering, if the GEDA framework includes a tool for unrolling sequential 
circuits at gate level. With unrolling sequential circuits I mean, if you have 
a sequential circuit which obtains the input sequence I_i and generates the 
output sequence O_i, the m time frames (=clock cycles) unrolled cicuit obtains 
the inputs I_i concurrently and generates the outputs O_i of all m time frames 
concurrently.

As an example, I drew the circuit below: It consists of a flip-flop and an and 
gate.


                  ---
I_i ->--==========|&|--*---> O_i
        |         ---  |
        |              |
        |     ----     |
        ------|FF|<-----
              ----

If I unroll m=2 time frames, this circuit with two inputs and two outputs is 
obtained. The inputs of the even time frames of the original circuit are 
applied to one of the inputs, the inputs of the odd time frames to the other. 
Similar for the outputs.


                  ---
I_2i ->-==========|&|--*---> O_2i
        |         ---  |                 ---
        |              ------------======|&|--*---O_2i+1
        |     ----                 |     ---  |
        ------|FF|<---------       |          |
              ----         |     I_2i+1       |
                           |                  |
                           |                  |
                           --------------------


Thanks.

Rainer.

- -- 
Rainer Dorsch
Abt. Rechnerarchitektur  e-mail:rainer.dorsch@informatik.uni-stuttgart.de
Uni Stuttgart            Tel.: +49-711-7816-215 / Fax: +49-711-7816-288
Breitwiesenstr. 20-22    D-70565 Stuttgart


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