llvm-project/libclc/generic/lib/math/exp_helper.cl

70 lines
2.2 KiB
Common Lisp

/*
* Copyright (c) 2014, 2015 Advanced Micro Devices, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <clc/clc.h>
#include "math.h"
#include "tables.h"
#ifdef cl_khr_fp64
#pragma OPENCL EXTENSION cl_khr_fp64 : enable
_CLC_DEF double __clc_exp_helper(double x, double x_min, double x_max, double r, int n) {
int j = n & 0x3f;
int m = n >> 6;
// 6 term tail of Taylor expansion of e^r
double z2 = r * fma(r,
fma(r,
fma(r,
fma(r,
fma(r, 0x1.6c16c16c16c17p-10, 0x1.1111111111111p-7),
0x1.5555555555555p-5),
0x1.5555555555555p-3),
0x1.0000000000000p-1),
1.0);
double2 tv = USE_TABLE(two_to_jby64_ep_tbl, j);
z2 = fma(tv.s0 + tv.s1, z2, tv.s1) + tv.s0;
int small_value = (m < -1022) || ((m == -1022) && (z2 < 1.0));
int n1 = m >> 2;
int n2 = m-n1;
double z3= z2 * as_double(((long)n1 + 1023) << 52);
z3 *= as_double(((long)n2 + 1023) << 52);
z2 = ldexp(z2, m);
z2 = small_value ? z3: z2;
z2 = isnan(x) ? x : z2;
z2 = x > x_max ? as_double(PINFBITPATT_DP64) : z2;
z2 = x < x_min ? 0.0 : z2;
return z2;
}
#endif // cl_khr_fp64