95 lines
		
	
	
		
			4.0 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			95 lines
		
	
	
		
			4.0 KiB
		
	
	
	
		
			C
		
	
	
	
/* --------------------------------------------------------------  */
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/* (C)Copyright 2007,2008,                                         */
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/* International Business Machines Corporation                     */
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/* All Rights Reserved.                                            */
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/*                                                                 */
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/* Redistribution and use in source and binary forms, with or      */
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/* without modification, are permitted provided that the           */
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/* following conditions are met:                                   */
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/*                                                                 */
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/* - Redistributions of source code must retain the above copyright*/
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/*   notice, this list of conditions and the following disclaimer. */
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/*                                                                 */
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/* - Redistributions in binary form must reproduce the above       */
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/*   copyright notice, this list of conditions and the following   */
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/*   disclaimer in the documentation and/or other materials        */
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/*   provided with the distribution.                               */
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/*                                                                 */
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/* - Neither the name of IBM Corporation nor the names of its      */
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/*   contributors may be used to endorse or promote products       */
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/*   derived from this software without specific prior written     */
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/*   permission.                                                   */
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/*                                                                 */
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/* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND          */
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/* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,     */
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/* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF        */
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/* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE        */
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/* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR            */
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/* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,    */
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/* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT    */
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/* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;    */
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/* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)        */
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/* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN       */
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/* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR    */
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/* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,  */
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/* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.              */
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/* --------------------------------------------------------------  */
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/* PROLOG END TAG zYx                                              */
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#ifdef __SPU__
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#ifndef _ATAN2F4_H_
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#define _ATAN2F4_H_	1
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#include <spu_intrinsics.h>
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#include "divf4.h"
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#include "atanf4.h"
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/*
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 * FUNCTION
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 *  vector float _atan2f4(vector float y, vector float x)
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 *
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 * DESCRIPTION
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 *  The atan2f4 function returns a vector containing the angles
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 *  whose tangets are y/x for the corresponding elements of the
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 *  input vectors.
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 *
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 *  The reason this function exists is to use the signs of the
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 *  arguments to determine the quadrant of the result. Consider
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 *  sin(x)/cos(x) on the domain (-pi, pi]. Four quadrants are
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 *  defined by the signs of sin and cos on this domain.
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 *
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 *  Special Cases:
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 *	- If the corresponding elements of x and y are zero, the 
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 *    resulting element is undefined.
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 *
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 */
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static __inline vector float _atan2f4(vector float y, vector float x)
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{
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    vector float pi   = spu_splats((float)SM_PI);
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    vector float zero = spu_splats(0.0f);
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    vector unsigned int quad1;
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    vector unsigned int quad4;
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    vector float result;
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    vector unsigned int xlt0;
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    vector unsigned int yge0;
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    vector unsigned int ylt0;
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    xlt0 = (vec_uint4)spu_rlmaska((vec_int4)x, 31);
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    ylt0 = (vec_uint4)spu_rlmaska((vec_int4)y, 31);
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    yge0 = spu_cmpeq(ylt0, (vec_uint4)zero);
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    quad1 = spu_and(ylt0, xlt0);
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    quad4 = spu_and(yge0, xlt0);
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    result = _atanf4(_divf4(y,x));
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    result = spu_sel(result, spu_sub(result, pi), quad1);
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    result = spu_sel(result, spu_add(result, pi), quad4);
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    return result;
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}
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#endif /* _ATAN2F4_H_ */
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#endif /* __SPU__ */
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