I want to design a divider using cordic function, for high number / low number (30/2) can anyone help me.?

I have already design the divider using cordic, but this is working only for when numerator is low and denomerator is high.

for example : x/y , 6/20 = 0.3. but when i give 20/6 it shows output is 1.

x = 6;

y = 20;

z = 0;

format long

k = zeros(20,3);

for i = 1:20

if x > 0

x = x - y*2^(-i);

z = z + 2^(-i);

else

x = x + y*2^(-i);

z = z - 2^(-i);

end

k(i,:) = [i 6/20 z];

end

Can anyone help ,how to design the divider using the cordic for higher number / Lower number (eg : 30/2).

Answer 1

[Walter Roberson]

Do not start with i=1. Start with i being the negative of the number of bits before the decimal place.

I believe that your else is incorrect. I believe you should be working with 2^(-(i-1)) so that you "undo" the previous step

[Walter Roberson]

In the case where your numerator and denominator are both non-negative or both negative, then you expect a non-negative output; take the absolute values of numerator and denominator, set a flag indicating that you are expecting non-negative, and proceed.

In the case where either numerator or denominator are negative, but not both, then you expect a negative output; take the absolute values of numerator and demoninator, set a flag indicating that you are expecting negative, and proceed.

You are now certain to not be working with negative.

At each step, calculate

 x_new = x - y*2^(-i); 

If x_new is positive, then

 x = x_new;
 z = z + 2^(-i);

and otherwise do not change x or z; either way, continue the loop. Stop when x is 0.

[Walter Roberson]

oh, and at the end if the negative flag is set then take negative of the answer.