Re: [Discuss-gnuradio] sign_extend.v !!!!

[Josh Blum]

http://en.wikipedia.org/wiki/Sign_extension

On 03/13/2011 07:47 PM, Alaa Salaheldin wrote:
> Can anyone please help me to understand what's going on in sign_extend.v ,
> this macro is initiated in the cic_decim.v
> 
> sign_extend #(bw,bw+maxbitgain)
>       ext_input (.in(signal_in),.out(signal_in_ext));
> 
> 
> when i opened the macro i couldn't understand it's function
> 
> // Sign extension "macro"
> // bits_out should be greater than bits_in
> 
> module sign_extend (in,out);
> parameter bits_in=0;  // FIXME Quartus insists on a default
> parameter bits_out=0;
>  input [bits_in-1:0] in;
> output [bits_out-1:0] out;
>  assign out = {{(bits_out-bits_in){in[bits_in-1]}},in};
> endmodule
> 
> Thanks in advance.
> 
> 
> 
> 
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