2007-09-29 02:44:24 +08:00
|
|
|
/* -------------------------------------------------------------- */
|
2008-09-05 01:50:56 +08:00
|
|
|
/* (C)Copyright 2001,2008, */
|
2007-09-29 02:44:24 +08:00
|
|
|
/* International Business Machines Corporation, */
|
|
|
|
|
/* Sony Computer Entertainment, Incorporated, */
|
|
|
|
|
/* Toshiba 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. */
|
|
|
|
|
/* */
|
|
|
|
|
/* 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 _SQRTF4_H_
|
|
|
|
|
#define _SQRTF4_H_ 1
|
|
|
|
|
|
|
|
|
|
#include <spu_intrinsics.h>
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* FUNCTION
|
|
|
|
|
* vector float _sqrtf4(vector float in)
|
|
|
|
|
*
|
|
|
|
|
* DESCRIPTION
|
|
|
|
|
* The _sqrtf4 function computes the square root of the vector input "in"
|
|
|
|
|
*and returns the result.
|
|
|
|
|
*
|
|
|
|
|
*/
|
|
|
|
|
static __inline vector float _sqrtf4(vector float in)
|
|
|
|
|
{
|
|
|
|
|
vec_uint4 exp, valid;
|
|
|
|
|
vec_uint4 mask = spu_splats((unsigned int)0xFF000000);
|
|
|
|
|
vec_uint4 half = spu_splats((unsigned int)0x00800000);
|
|
|
|
|
vec_float4 one = spu_splats(1.0f);
|
|
|
|
|
vec_float4 three = spu_splats(3.0f);
|
|
|
|
|
vec_float4 x, y0, y1, y1_n1, y1_p1, y1_p2, y1_p3;
|
|
|
|
|
vec_float4 mant, err, err_p1, err_p2, err_p3;
|
|
|
|
|
vec_float4 out;
|
|
|
|
|
|
|
|
|
|
/* Compute the mantissa of the result seperately from
|
|
|
|
|
* the exponent to assure complete accuracy over the allowable
|
|
|
|
|
* input range. The mantissa is computed for inputs in the
|
|
|
|
|
* range [0.5, 2.0).
|
|
|
|
|
*/
|
|
|
|
|
x = spu_sel(in, one, mask);
|
|
|
|
|
y0 = spu_rsqrte(x);
|
|
|
|
|
|
|
|
|
|
/* Perform one iteration of the Newton-Raphsom method in single precision
|
|
|
|
|
* arithmetic.
|
|
|
|
|
*/
|
|
|
|
|
y1 = spu_mul(spu_nmsub(x, spu_mul(y0, y0), three),
|
|
|
|
|
spu_mul(y0, (vec_float4)(spu_sub((vec_uint4)(x), half))));
|
|
|
|
|
|
|
|
|
|
/* Correct the result for possible error. The range of error is -3 to +1.
|
|
|
|
|
* Identify the extent of the error and correct for it.
|
|
|
|
|
*/
|
|
|
|
|
y1_p3 = (vec_float4)spu_add((vec_uint4)(y1), 3);
|
|
|
|
|
y1_p2 = (vec_float4)spu_add((vec_uint4)(y1), 2);
|
|
|
|
|
y1_p1 = (vec_float4)spu_add((vec_uint4)(y1), 1);
|
|
|
|
|
y1_n1 = (vec_float4)spu_add((vec_uint4)(y1), -1);
|
|
|
|
|
|
|
|
|
|
err = spu_nmsub(y1, y1, x);
|
|
|
|
|
err_p1 = spu_nmsub(y1_p1, y1_p1, x);
|
|
|
|
|
err_p2 = spu_nmsub(y1_p2, y1_p2, x);
|
|
|
|
|
err_p3 = spu_nmsub(y1_p3, y1_p3, x);
|
|
|
|
|
|
|
|
|
|
mant = spu_sel(y1_n1, y1, spu_cmpgt((vec_int4)(err), -1));
|
|
|
|
|
mant = spu_sel(mant, y1_p1, spu_cmpgt((vec_int4)(err_p1), -1));
|
|
|
|
|
mant = spu_sel(mant, y1_p2, spu_cmpgt((vec_int4)(err_p2), -1));
|
|
|
|
|
mant = spu_sel(mant, y1_p3, spu_cmpgt((vec_int4)(err_p3), -1));
|
|
|
|
|
|
|
|
|
|
/* Compute the expected exponent. If the exponent is zero or the input is
|
|
|
|
|
* negative, then set the result to zero.
|
|
|
|
|
*/
|
|
|
|
|
exp = spu_rlmask(spu_add((vec_uint4)(in), (vec_uint4)(one)), -1);
|
|
|
|
|
|
|
|
|
|
valid = spu_cmpgt(spu_and((vec_int4)(in), (vec_int4)(mask)), 0);
|
|
|
|
|
|
|
|
|
|
/* Merge the computed exponent and mantissa.
|
|
|
|
|
*/
|
|
|
|
|
out = spu_and(spu_sel(mant, (vec_float4)(exp), spu_splats(0xFF800000)), (vec_float4)(valid));
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
return (out);
|
|
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
#endif /* _SQRTF4_H_ */
|
|
|
|
|
#endif /* __SPU__ */
|
