Error observed in using bitsll and bitsra

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Life is Wonderful 2022-9-22

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https://ww2.mathworks.cn/matlabcentral/answers/1810095-error-observed-in-using-bitsll-and-bitsra

编辑： Life is Wonderful 2022-9-28

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When utilizing bitsll and bitsra, an error was noticed.

I have the following code and intend to utilize Embedded.fi [fixed point ] as double implementation show in case -1.

Can someone please show me how to code correctly and help me understand what I'm missing in cases 2 and 3?

It would be nice if I could do cases 2 and 3 in a single function/ single solution.

Thank you very much.

% case -1 : double

k = linspace(-12,12,10); 
for i = 1 : length(k)
    a =  2 ^ k(i)
end
a = 2.4414e-04
a = 0.0016
a = 0.0098
a = 0.0625
a = 0.3969
a = 2.5198
a = 16
a = 101.5937
a = 645.0796
a = 4096

% case -2: Embdedded fi ,fixed point - right shift

k = fi(linspace(-12,12,10),1,32,27);
a = int8(1);
for i = 1 : length(k)
%   fxpOut = bitsra(a,k(i))
  disp(bin(bitsra(a,k(i))))
end
Error using bitsra
K must be numeric, scalar, real, integer-valued, and greater than or equal to zero in BITSRA(A,K).

Error in embedded.fi/bitsra (line 38)
    y = bitsra(x, double(kin));

% case - 3: Embdedded fi ,fixed point - left shift

k = fi(linspace(-12,12,10),1,32,27);
a = int8(1);
for i = 1 : length(k)
  fxpOut = bitsll(a,k(i))
  disp(bin(bitsll(a,k(i))))
end

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Richard McCormack 2022-9-26

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Hi @Life is Wonderful,

I am happy that you made progress!

I made some adjustments to your code to make it work for code generation.

But maybe there is a reason that you can't use abs. If that is the case, please let me know why you can't use abs.

function scratch
coder.extrinsic('bin');
K = [-12,12];
coder.unroll;
for i = 1:length(K)
    if sign(K(i)) < 0  % Bitsliceget to know bitposition and do a bitand for sign
        % Negative
        b = fi(bitsra(1,abs(K(i))));
        disp(bin(b))
    else
        % Positive
        b_i = fi(bitsra(1,abs(K(i))));
        disp(bin(b_i))
    end
end
end