| /* |
| (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_ */ |