140 lines
6.2 KiB
C
140 lines
6.2 KiB
C
/* -------------------------------------------------------------- */
|
|
/* (C)Copyright 2006,2007, */
|
|
/* International Business Machines Corporation */
|
|
/* All Rights Reserved. */
|
|
/* */
|
|
/* Redistribution and use in source and binary forms, with or */
|
|
/* without modification, are permitted provided that the */
|
|
/* following conditions are met: */
|
|
/* */
|
|
/* - Redistributions of source code must retain the above copyright*/
|
|
/* notice, this list of conditions and the following disclaimer. */
|
|
/* */
|
|
/* - Redistributions in binary form must reproduce the above */
|
|
/* copyright notice, this list of conditions and the following */
|
|
/* disclaimer in the documentation and/or other materials */
|
|
/* provided with the distribution. */
|
|
/* */
|
|
/* - Neither the name of IBM Corporation nor the names of its */
|
|
/* contributors may be used to endorse or promote products */
|
|
/* derived from this software without specific prior written */
|
|
/* permission. */
|
|
/* Redistributions of source code must retain the above copyright */
|
|
/* notice, this list of conditions and the following disclaimer. */
|
|
/* */
|
|
/* Redistributions in binary form must reproduce the above */
|
|
/* copyright notice, this list of conditions and the following */
|
|
/* disclaimer in the documentation and/or other materials */
|
|
/* provided with the distribution. */
|
|
/* */
|
|
/* Neither the name of IBM Corporation nor the names of its */
|
|
/* contributors may be used to endorse or promote products */
|
|
/* derived from this software without specific prior written */
|
|
/* permission. */
|
|
/* */
|
|
/* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND */
|
|
/* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, */
|
|
/* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF */
|
|
/* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE */
|
|
/* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR */
|
|
/* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, */
|
|
/* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT */
|
|
/* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; */
|
|
/* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) */
|
|
/* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN */
|
|
/* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR */
|
|
/* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, */
|
|
/* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
|
|
/* -------------------------------------------------------------- */
|
|
/* PROLOG END TAG zYx */
|
|
#ifdef __SPU__
|
|
#ifndef _HYPOTF4_H_
|
|
#define _HYPOTF4_H_ 1
|
|
|
|
#include <spu_intrinsics.h>
|
|
|
|
#include "sqrtf4.h"
|
|
|
|
/*
|
|
* FUNCTION
|
|
* vector float _hypotf4(vector float x, vector float y)
|
|
*
|
|
* DESCRIPTION
|
|
* The function hypotf4 returns a float vector in which each element is
|
|
* the square root of the sum of the squares of the corresponding
|
|
* elements of x and y. In other words, each element is sqrt(x^2 + y^2).
|
|
*
|
|
* The purpose of this function is to avoid overflow during
|
|
* intermediate calculations, and therefore it is slower than
|
|
* simply calcualting sqrt(x^2 + y^2).
|
|
*
|
|
* This function is performed by factoring out the larger of the 2
|
|
* input exponents and moving this factor outside of the sqrt calculation.
|
|
* This will minimize the possibility of over/underflow when the square
|
|
* of the values are calculated. Think of it as normalizing the larger
|
|
* input to the range [1,2).
|
|
*
|
|
*
|
|
* Special Cases:
|
|
* - hypot(x, +/-0) returns |x|
|
|
* - hypot(+/- infinity, y) returns +infinity
|
|
* - hypot(+/- infinity, NaN) returns +infinity
|
|
*
|
|
*/
|
|
|
|
|
|
static __inline vector float _hypotf4(vector float x, vector float y)
|
|
{
|
|
vector unsigned int emask = spu_splats(0x7F800000u);
|
|
vector unsigned int mmask = spu_splats(0x007FFFFFu);
|
|
vector signed int bias = spu_splats(0x3F800000);
|
|
vector float inf = (vec_float4)spu_splats(0x7F800000);
|
|
vector float onef = spu_splats(1.0f);
|
|
vector float sbit = spu_splats(-0.0f);
|
|
vector float max, max_e, max_m;
|
|
vector float min, min_e, min_m;
|
|
vector unsigned int xgty;
|
|
vector float sum;
|
|
vector float result;
|
|
|
|
/* Only need absolute values for this function */
|
|
x = spu_andc(x, sbit);
|
|
y = spu_andc(y, sbit);
|
|
xgty = spu_cmpgt(x,y);
|
|
|
|
max = spu_sel(y,x,xgty);
|
|
min = spu_sel(x,y,xgty);
|
|
|
|
/* Extract exponents and mantissas */
|
|
max_e = (vec_float4)spu_and((vec_uint4)max, emask);
|
|
max_m = (vec_float4)spu_and((vec_uint4)max, mmask);
|
|
min_e = (vec_float4)spu_and((vec_uint4)min, emask);
|
|
min_m = (vec_float4)spu_and((vec_uint4)min, mmask);
|
|
|
|
/* Adjust the exponent of the smaller of the 2 input values by
|
|
* subtracting max_exp from min_exp.
|
|
*/
|
|
vec_int4 min_e_int = spu_sub((vec_int4)min_e, (vec_int4)max_e);
|
|
min_e = (vec_float4)spu_add(min_e_int, bias);
|
|
|
|
/* If the new min exponent is too small, just set it to 0. It
|
|
* wouldn't contribute to the final result in either case.
|
|
*/
|
|
min_e = spu_sel(min_e, sbit, spu_cmpgt(sbit, min_e));
|
|
|
|
/* Combine new exponents with original mantissas */
|
|
max = spu_or(onef, max_m);
|
|
min = spu_or(min_e, min_m);
|
|
|
|
sum = _sqrtf4(spu_madd(max, max, spu_mul(min, min)));
|
|
sum = spu_mul(max_e, sum);
|
|
|
|
/* Special case: x = +/- infinity */
|
|
result = spu_sel(sum, inf, spu_cmpeq(x, inf));
|
|
|
|
return result;
|
|
}
|
|
|
|
#endif /* _HYPOTF4_H_ */
|
|
#endif /* __SPU__ */
|