YAC - Yet Another CORDIC Core :: Overview

Project maintainers


Name: yac
Created: Mar 2, 2014
Updated: Jun 22, 2015
SVN Updated: Jun 22, 2015
SVN: Browse
Latest version: download
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Other project properties

Category: Arithmetic core
Language: VHDL
Development status: Alpha
Additional info: Design done, FPGA proven, Specification done
WishBone Compliant: Yes
License: LGPL


CORDIC is the acronym for COordinate Rotation DIgital Computer and allows a hardware efficient calculation of various functions like - atan, sin, cos - atanh, sinh, cosh, - division, multiplication.
Hardware efficient means, that only shifting, additions and substractions in combination with table-lookup is required. This makes it suitable for a realization in digital hardware. Good introductions can be found in [1][2][3][4].

IP core block symbol (png

The following six CORDIC modes are supported:
- trigonometric rotation
- trigonometric vectoring
- linear rotation
- linear vectoring
- hyperbolic rotation
- hyperbolic vectoring

Furthermore, the CORDIC algorithm is implemented for iterative processing which means, that the IP-core is started with a set of input data and after a specific amount of clock cycles, the result is available. No parallel data can be processed.

In addition to an IP-core written in VHDL, a bit-accurate C-model is provided. This C-model can be compiled as mex for a usage with Octave or Matlab. Therefore, this C-model allows a bit-accurate analysis of the CORDIC performance on a higher level.


- C-model implementation is done
- RTL model implementation is done
- RTL model is verified against C-model
- Wishbone-bus wrapper is added - Included into a small SoC, tested on a spartan-3 FPGA

Open issues and future steps

The next steps are

- Circuit optimizations
- Numerical optimizations

and the future plans are

- Hyperbolic range extension
- Floating point CORDIC


[1] Andraka, Ray; A survey of CORDIC algorithms for FPGA based computers, 1989
[2] Hu, Yu Hen; CORDIC-Based VLSI Architectures for Digital Signal Processing, 1992
[3] CORDIC on wikibook:
[4] CORDIC on wikipedia:
[5] David, Herbert; Meyr, Heinricht; CORDIC Algorithms and Architectures

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