83 lines
2.9 KiB
C
83 lines
2.9 KiB
C
/*
|
|
(C) Copyright 2001,2006,
|
|
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 names of the copyright holders nor the names of their
|
|
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.
|
|
*/
|
|
#ifndef _SCALBN_H_
|
|
#define _SCALBN_H_ 1
|
|
|
|
#include <spu_intrinsics.h>
|
|
#include "headers/vec_literal.h"
|
|
|
|
/* scalbn computes x * 2^exp. This function variant computes the result
|
|
* and handles overflow, underflow, and denorms by breaking the problem
|
|
* into:
|
|
* exp = MAX(exp, -2044)
|
|
* exp = MIN(exp, 2046)
|
|
* e1 = exp / 2
|
|
* e2 = exp - e1;
|
|
* x * 2^e1 * 2^e2
|
|
*/
|
|
static __inline double _scalbn(double x, int exp)
|
|
{
|
|
vec_int4 e, e1, e2;
|
|
vec_int4 min = VEC_SPLAT_S32(-2044);
|
|
vec_int4 max = VEC_SPLAT_S32(2046);
|
|
vec_uint4 cmp_min, cmp_max;
|
|
vec_uint4 shift = VEC_LITERAL(vec_uint4, 20, 32, 20, 32);
|
|
vec_double2 f1, f2;
|
|
vec_double2 in, out;
|
|
|
|
in = spu_promote(x, 0);
|
|
e = spu_promote(exp, 0);
|
|
|
|
/* Clamp the specified exponent to the range -2044 to 2046.
|
|
*/
|
|
cmp_min = spu_cmpgt(e, min);
|
|
cmp_max = spu_cmpgt(e, max);
|
|
e = spu_sel(min, e, cmp_min);
|
|
e = spu_sel(e, max, cmp_max);
|
|
|
|
/* Generate the factors f1 = 2^e1 and f2 = 2^e2
|
|
*/
|
|
e1 = spu_rlmaska(e, -1);
|
|
e2 = spu_sub(e, e1);
|
|
|
|
f1 = (vec_double2)spu_sl(spu_add(e1, 1023), shift);
|
|
f2 = (vec_double2)spu_sl(spu_add(e2, 1023), shift);
|
|
|
|
/* Compute the product x * 2^e1 * 2^e2
|
|
*/
|
|
out = spu_mul(spu_mul(in, f1), f2);
|
|
|
|
return (spu_extract(out, 0));
|
|
}
|
|
#endif /* _SCALBN_H_ */
|