Convert fraction to binary in SV

SystemVerilog
, ,
1

Hi,

I want to convert fractional part - kfrac in the below task to binary. I tried to use the $realtobits system task, but this will compromise on the precision as I will need only 5 bits starting from LSB out of 64 bits. So, what’s the best way to convert it to binary in SV?

 
task compute_k();
    target_res = $urandom_range(200,45);
    k = (rterm_target - inductor_res) * 8/(target_res - inductor_res);
    kint = $rtoi(k);
    kfrac = k - kint;
    $display("Kint :: %d, Kfrac :: %f, K :: %f", kint, kfrac, k);
endtask

Thanks

2

In reply to nimitz_class:

It would help to show the declarations of all variables and include a set of example values you are expecting.

3

In reply to dave_59:

In reply to nimitz_class:
It would help to show the declarations of all variables and include a set of example values you are expecting.

module computeK();
  
localparam real rterm_target = 45;
localparam real inductor_res = 7;
localparam real static_legs  = 5;
localparam real target_res   = 200;
 
real k, kfrac;
int kint;

  task compute_k();
    k = (rterm_target - inductor_res) * 8/(target_res - inductor_res);
    kint = $rtoi(k);
    kfrac = k - kint;
    $display("Kint :: %d, Kfrac :: %f, K :: %f", kint, kfrac, k);
  endtask

  initial begin
    compute_k();
  end
  
endmodule

Sim result : Kint :: 1, Kfrac :: 0.575130, K :: 1.575130

I want to convert 0.575 to binary

4

In reply to nimitz_class:

It seems like you want to convert floating point to fixed point.