The Museum of HP Calculators

HP Forum Archive 18

 CORDIC Trigonometric Algorithm on an HP17BIIMessage #1 Posted by Charles on 13 Mar 2008, 5:20 p.m. There has a great deal of very useful discussion on programming trigonometric functions on financial calculators such as the HP 17BII. Has anyone considered putting a CORDIC algorithm on this calculator or is it just too inefficient compared with other approaches ? I'd try but think that it is beyond my abilities.

 Re: CORDIC Trigonometric Algorithm on an HP17BIIMessage #2 Posted by Chris Dean on 13 Mar 2008, 5:37 p.m.,in response to message #1 by Charles Charles I have found this document on the internet http://www.fpga-guru.com/files/crdcsrvy.pdf Is it a good reference or do you have any other reference material that is better? Chris

 Re: CORDIC Trigonometric Algorithm on an HP17BIIMessage #3 Posted by Eric Smith on 13 Mar 2008, 7:13 p.m.,in response to message #1 by Charles The best general reference on algorithms for elementary functions, including both "traditional" and "shift-and-add" algorithms like CORDIC, is "Elementary Functions: Algorithms and Implementation", 2nd Edition, by Jean-Michel Muller. I'm not very familiar with the capabilities of the 17BII, but implementing a decimal CORDIC generally requires two nested loops, and a table of precomputed constants with basically one table entry per digit of precision. I suspect that series approximations are far easier to implement on the 17BII than CORDIC would be.

 Re: CORDIC Trigonometric Algorithm on an HP17BIIMessage #4 Posted by Gerson W. Barbosa on 13 Mar 2008, 8:41 p.m.,in response to message #3 by Eric Smith Quote: I suspect that series approximations are far easier to implement on the 17BII than CORDIC would be. And a software implementation of CORDIC would not be efficient since it is more suitable for hardware implementation, as you know. Anyway, Charles could try to convert an HP-32Sii/33s program I presented in this thread (Message #4), which is translation of a TI program: As of series and polynomial approximations on the HP-17BII, here we have them in six flavors: Regards, Gerson.

 Re: CORDIC Trigonometric Algorithm on an HP17BIIMessage #5 Posted by Eric Smith on 14 Mar 2008, 12:14 a.m.,in response to message #4 by Gerson W. Barbosa Binary CORDIC is actually pretty efficient on most RISC processors.

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