Function is not defined for values of class embedded.fi when using HDL coder

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Sam
Sam on 2 Apr 2013
Answered: Dhananjay Kumar on 17 Sep 2020
Hi,
When I am experimenting in converting matlab code into vhdl with hdl coder, I am getting the error such as Function 'log' is not defined for values of class 'embedded.fi' or Function 'exp' is not defined for values of class 'embedded.fi'.
The specific block of code comes from the block:
f_0 = fi( 0, 0, 1, 0, fm ); % 133.33333;
f_sp = fi( 200*fi( 1/3, 0, 14, 15 ), 0, 14, 7, fm ); % 66.66667;
brkfrq = fi( 1000, 0, 11, 0, fm );
brkpt = fi( fi_div( (brkfrq - f_0), f_sp ), 0, 14, 10, fm );
logstep = fi( 1.0711703, 0, 14, 13, fm );
linpts = (f<brkfrq);
z = fi( fi( 0, 0, 1, 0 )*f, 0, 6, 0, fm );
z( linpts ) = fi( fi_div( (f( linpts ) - f_0), f_sp ), 0, 6, 0, fm );
% error with line below.
z( ~(linpts~=0) ) = fi( brkpt + (log( fi_div( f( ~(linpts~=0) ), brkfrq ) )) ./ log( logstep ), 0, 6, 0, fm );
The original matlab code is from audspec.m of rastamat. I have tried converting fixed point to double before calling log(), but then another error pops up.
Thanks,

Accepted Answer

Tim McBrayer
Tim McBrayer on 2 Apr 2013
As the error message states, there is no fixed-point version of the 'log' or 'exp' commands in MATLAB HDL Coder. The complete list of functions that have fixed point versions and are supported for HDL code generation is at http://www.mathworks.com/help/hdlcoder/ug/fixed-point-run-time-library-support.html.

More Answers (1)

Dhananjay Kumar
Dhananjay Kumar on 17 Sep 2020
Here is the link to check function supported for code generation using fixed point arithmetic

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