newlib-cygwin/newlib/libm/machine/spu/headers/atan2f4.h

107 lines
4.8 KiB
C

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/* (C)Copyright 2006,2007, */
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/* PROLOG END TAG zYx */
#ifdef __SPU__
#ifndef _ATAN2F4_H_
#define _ATAN2F4_H_ 1
#include <spu_intrinsics.h>
#include "divf4.h"
#include "atanf4.h"
/*
* FUNCTION
* vector float _atan2f4(vector float y, vector float x)
*
* DESCRIPTION
* The atan2f4 function returns a vector containing the angles
* whose tangets are y/x for the corresponding elements of the
* input vectors.
*
* The reason this function exists is to use the signs of the
* arguments to determine the quadrant of the result. Consider
* sin(x)/cos(x) on the domain (-pi, pi]. Four quadrants are
* defined by the signs of sin and cos on this domain.
*
* Special Cases:
* - If the corresponding elements of x and y are zero, the
* resulting element is undefined.
*
*/
static __inline vector float _atan2f4(vector float y, vector float x)
{
vector float pi = spu_splats((float)SM_PI);
vector float zero = spu_splats(0.0f);
vector unsigned int quad1;
vector unsigned int quad4;
vector float result;
vector unsigned int xlt0;
vector unsigned int yge0;
vector unsigned int ylt0;
xlt0 = (vec_uint4)spu_rlmaska((vec_int4)x, 31);
ylt0 = (vec_uint4)spu_rlmaska((vec_int4)y, 31);
yge0 = spu_cmpeq(ylt0, (vec_uint4)zero);
quad1 = spu_and(ylt0, xlt0);
quad4 = spu_and(yge0, xlt0);
result = _atanf4(_divf4(y,x));
result = spu_sel(result, spu_sub(result, pi), quad1);
result = spu_sel(result, spu_add(result, pi), quad4);
return result;
}
#endif /* _ATAN2F4_H_ */
#endif /* __SPU__ */