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/* -------------------------------------------------------------- */
/* (C)Copyright 2007,2008, */
/* 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. */
/* */
/* 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 _NEXTAFTERD2_H_
#define _NEXTAFTERD2_H_ 1
#include <spu_intrinsics.h>
/*
* FUNCTION
* vector double _nextafterd2(vector double x, vector double y)
*
* DESCRIPTION
* The nextafterf4 function returns a vector containing the next representable
* floating-point number after the element of x, in the direction of the
* corresponding element y.
*
* Special Cases:
* - nextafter(NaN, y) = NaN
* - nextafter(x, NaN) = NaN
* - x = largest finite value, y = infinity, result is undefined
* - x = largest finite negative value, y = -infinity, result is undefined
* - x != y, and result = 0, considered an underflow
*
*/
static __inline vector double _nextafterd2(vector double x, vector double y)
{
vec_double2 n1ulp = (vec_double2)spu_splats(0x8000000000000001ull);
vector unsigned char mov_carry = {0x80,0x80,0x80, 7, 0x80,0x80,0x80,0x80,
0x80,0x80,0x80,15, 0x80,0x80,0x80,0x80};
vec_double2 zerod = spu_splats(0.0);
vec_llong2 one = spu_splats(1ll);
vec_ullong2 xlt0, xgty, xeqy, xeq0;
vec_llong2 xllong;
vec_int4 carry;
vec_llong2 delta, deltap1;
vec_double2 result;
/* Compiler Bug. Replace xtmp/ytmp with x/y when spu_cmpgt(x,y) doesn't change x/y!*/
volatile vec_double2 xtmp = x;
volatile vec_double2 ytmp = y;
/*
* The idea here is to treat x as a signed long long value, which allows us to
* add or subtact one to/from it to get the next representable value.
*/
xeq0 = spu_cmpeq(xtmp, zerod);
xlt0 = spu_cmpgt(zerod, xtmp);
xeqy = spu_cmpeq(xtmp, ytmp);
xgty = spu_cmpgt(xtmp, ytmp);
/* If x = -0.0, set x = 0.0 */
x = spu_andc(x, (vec_double2)xeq0);
xllong = (vec_llong2)x;
/* Determine value to add to x */
delta = (vec_llong2)spu_xor(xgty, xlt0);
//deltap1 = delta + one;
carry = spu_genc((vec_int4)delta, (vec_int4)one);
carry = spu_shuffle(carry, carry, mov_carry);
deltap1 = (vec_llong2)spu_addx((vec_int4)delta, (vec_int4)one, (vec_int4)carry);
delta = spu_sel(deltap1, delta, (vec_ullong2)delta);
//xllong = xllong + delta;
carry = spu_genc((vec_int4)xllong, (vec_int4)delta);
carry = spu_shuffle(carry, carry, mov_carry);
xllong = (vec_llong2)spu_addx((vec_int4)xllong, (vec_int4)delta, (vec_int4)carry);
/* Fix the case of x = 0, and answer should be -1 ulp */
result = spu_sel((vec_double2)xllong, n1ulp, spu_and((vec_ullong2)delta, xeq0));
/*
* Special Cases
*/
/* x = y */
result = spu_sel(result, y, xeqy);
return result;
}
#endif /* _NEXTAFTERD2_H_ */
#endif /* __SPU__ */
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