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/* -------------------------------------------------------------- */
/* (C)Copyright 2006,2008, */
/* 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 _SCALBNF4_H_
#define _SCALBNF4_H_ 1
#include <spu_intrinsics.h>
/*
* FUNCTION
* vector float _scalbnf4(vector float x, vector signed int exp)
*
* DESCRIPTION
* The _scalbnf4 function returns a vector containing each element of x
* multiplied by 2^n computed efficiently. This function is computed
* without the assistance of any floating point operations and as such
* does not set any floating point exceptions.
*
* Special Cases:
* - if the exponent is 0, then x is either 0 or a subnormal, and the
* result will be returned as 0.
* - if the result if underflows, it will be returned as 0.
* - if the result overflows, it will be returned as FLT_MAX.
*
*/
static __inline vector float _scalbnf4(vector float x, vector signed int exp)
{
vec_int4 x_exp;
vec_uint4 zero;
vec_uint4 overflow;
vec_uint4 exp_mask = (vec_uint4)spu_splats(0x7F800000);
vec_float4 out;
/* Extract exponent from x. If the exponent is 0, then
* x is either 0 or a denorm and x*2^exp is a zero.
*/
x_exp = spu_and(spu_rlmask((vec_int4)x, -23), 0xFF);
zero = spu_cmpeq(x_exp, 0);
/* Compute the expected exponent and determine if the
* result is within range.
*/
x_exp = spu_add(exp, x_exp);
/* Check for zero or overflow of result.
* Note: set high bit of flags = 0, since we have to
* return -0 when x = -0
*/
zero = spu_rlmask(spu_orc(zero, spu_cmpgt(x_exp, 0)), -1);
overflow = spu_rlmask(spu_cmpgt(x_exp, 255), -1);
/* Merge the expect exponent with x's mantissa. Zero the
* result if underflow and force to max if overflow.
*/
out = spu_sel(x, (vec_float4)spu_rl(x_exp, 23), exp_mask);
out = spu_andc(out, (vec_float4)zero);
out = spu_or(out, (vec_float4)overflow);
return out;
}
#endif /* _SCALBNF4_H_ */
#endif /* __SPU__ */
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