shifter: shift last two values

[fanwel]

Hi all,

I want to have a shifter to shift the last two values of my input into the left (MSB) as the output.
For example, input: f=( 2,1,0,9,3) then the output will be y=(9,3,2,1,0).
It is possible I write this operation in VHDL?
Hope for your advise. Thank You

 

[TrickyDicky]

Yes, Im sure its possible. But your question isnt very clear. You ask to shift two values, but then you talk about shifting the MSB?
then the function of the output you show is a right shift, not a left shift.

So is it a bitwise shift, or a value you shift? do the outputs make up different parts of a larger number?

Please make what you want to do more clear.

 

[fanwel]

Hi TrickyDicky,

Sorry on that question, I'm wrong. Actually I want to shift the last two values of the input into the front (from right to left).
I try to write VHDL code using shifter but I dont know how to shift the values. Can you helps me.
Thanks for reply

 

[TrickyDicky]

are these input serially into a parrallel buffer, or are they input in parrallel and you simply want to move them around their input array?

 

[fanwel]

Hi TrickyDicky,

Yes, the inputs are in parallel and I want to move them around their input array.
Thanks for reply

 

[TrickyDicky]

then they dont need to be shifted. you just assign them to their specific new entries

type some_array_t is array(0 to 4) of integer;

output <= input(2 to 4) & input(0 to 1);

So now, lets assume input was (0,1,2,3,4);
output is now (2,3,4,0,1);

 

[fanwel]

Hi TrickyDicky,

Thanks for the idea. I will write the code and let you know if I get problems.
Many thanks