87 lines
3.0 KiB
C
87 lines
3.0 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 _ILOGB_H_
|
||
|
|
#define _ILOGB_H_ 1
|
||
|
|
|
||
|
|
#include <spu_intrinsics.h>
|
||
|
|
#include "headers/vec_literal.h"
|
||
|
|
#include <limits.h>
|
||
|
|
#include <math.h>
|
||
|
|
|
||
|
|
/* ilogb returns the signed exponent in the floating-point
|
||
|
|
* input. Special numbers include:
|
||
|
|
* Input Output
|
||
|
|
* ===== =====================
|
||
|
|
* INF FP_ILOGBNAN (INT_MAX)
|
||
|
|
* NAN FP_ILOGBNAN (INT_MAX)
|
||
|
|
* denorm exponent - leading zeros
|
||
|
|
* 0 FP_ILOGB0 (INT_MIN)
|
||
|
|
* else signed exponent
|
||
|
|
*/
|
||
|
|
|
||
|
|
static __inline int _ilogb(double x)
|
||
|
|
{
|
||
|
|
vec_uint4 v, exp, exp_0, mant, mask, count;
|
||
|
|
vec_uint4 flg_exp_0, flg_exp_max;
|
||
|
|
|
||
|
|
mask = VEC_SPLAT_U32(0x7FF);
|
||
|
|
|
||
|
|
/* Extract the exponent and mantissa.
|
||
|
|
*/
|
||
|
|
v = (vec_uint4)spu_promote(x, 0);
|
||
|
|
|
||
|
|
exp = spu_and(spu_rlmask(v, -20), mask);
|
||
|
|
|
||
|
|
mant = spu_and(v, VEC_LITERAL(vec_uint4, 0x000FFFFF, 0xFFFFFFFF, 0, 0));
|
||
|
|
|
||
|
|
/* Count the leading zeros in the mantissa for denorm handling
|
||
|
|
* and zero identification.
|
||
|
|
*/
|
||
|
|
count = spu_cntlz(mant);
|
||
|
|
count = spu_add(count, spu_and(spu_rlqwbyte(count, 4), spu_cmpeq(count, 32)));
|
||
|
|
|
||
|
|
flg_exp_0 = spu_cmpeq(exp, 0);
|
||
|
|
flg_exp_max = spu_cmpeq(exp, mask);
|
||
|
|
|
||
|
|
exp = spu_add(exp, -1023);
|
||
|
|
|
||
|
|
/* Determine the exponent if the input is a denorm or zero.
|
||
|
|
*/
|
||
|
|
exp_0 = spu_sel(spu_sub(spu_add(exp, 12), count), VEC_SPLAT_U32(FP_ILOGB0), spu_cmpeq(count, 64));
|
||
|
|
|
||
|
|
exp = spu_sel(spu_sel(exp, VEC_SPLAT_U32(FP_ILOGBNAN), flg_exp_max), exp_0, flg_exp_0);
|
||
|
|
|
||
|
|
return (spu_extract((vec_int4)(exp), 0));
|
||
|
|
}
|
||
|
|
#endif /* _ILOGB_H_ */
|