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This repository holds a CORDIC digital design written in VHDL. which can be used e.g. for integration in FPGA-based SOCs.

CORDIC is the acronym for COordinate Rotation DIgital Computer andallows a hardware efficient calculation of various functionslike - atan, sin, cos - atanh, sinh, cosh, - division, multiplication.Hardware efficient means, that only shifting, additions andsubtractions in combination with table-lookup is required. This makesit suitable for a realization in digital hardware. Goodintroductions can be found in [1][2][3][5].

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 iterativeprocessing which means, that the IP-core is startedwith a set of input data and after a specific amount ofclock cycles, the result isavailable. No parallel data can be processed.

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

For a more detailed documentation, see./doc/documentation.pdf

• 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
• Testing within an SOC is done (see./test_sys)

• Circuit optimizations
• Numerical optimizations

• ./c_octave contains a bit-accurate C-implementation of the YAC.This C-implementation is used for analyzing the performanceand to generate RTL testbench stimulus(cordic_iterative_test.m).The file cordic_iterative_code.m is used to create someVHDL/C-code automatically.
• ./rtl/vhdl Contains the VHDL implementation files
• ./doc Will contain a detailed documentation in future.
• ./test_sys Contains a test system to test the YAC on a spartan-3an board

• [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:http://en.wikibooks.org/wiki/Digital_Circuits/CORDIC
• [4] CORDIC on wikipedia:http://en.wikipedia.org/wiki/CORDIC
• [5] David, Herbert; Meyr, Heinricht; CORDIC Algorithms and Architectureshttp://www.eecs.berkeley.edu/newton/Classes/EE290sp99/lectures/ee290aSp996_1/cordic_chap24.pdf

                   Copyright Notice                                   This file is part of YAC - Yet Another CORDIC Core                  Copyright (c) 2014, Author(s), All rights reserved.                 YAC is free software; you can redistribute it and/or                modify it under the terms of the GNU Lesser General Public          License as published by the Free Software Foundation; either        version 3.0 of the License, or (at your option) any later version.  YAC is distributed in the hope that it will be useful,              but WITHOUT ANY WARRANTY; without even the implied warranty of      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU   Lesser General Public License for more details.                     You should have received a copy of the GNU Lesser General Public    License along with this library. If not, download it from           http://www.gnu.org/licenses/lgpl                                           Author(s):  Christian Haettich                 Email       feddischson@gmail.com