9743b99cd1
Doing so provides stability when compiling the builtins in a mode in which unqualified pointers may be interpreted as being in the generic address space, such as in OpenCL 3.0. We eventually want to provide 'generic' overloads of the builtins in libclc so this prepares the ground a little better. It could be argued that having the internal CLC helper functions be unqualified is more flexible, in case it's better for a target to have the pointers in the generic address space. This commits to the private address space for more stability across different OpenCL environments.
95 lines
3.1 KiB
Common Lisp
95 lines
3.1 KiB
Common Lisp
/*
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* Copyright (c) 2014 Advanced Micro Devices, Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifdef cl_khr_fp64
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#include "ep_log.h"
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#include <clc/clc.h>
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#include <clc/math/math.h>
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#include <clc/math/tables.h>
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#pragma OPENCL EXTENSION cl_khr_fp64 : enable
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#define LN0 8.33333333333317923934e-02
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#define LN1 1.25000000037717509602e-02
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#define LN2 2.23213998791944806202e-03
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#define LN3 4.34887777707614552256e-04
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#define LF0 8.33333333333333593622e-02
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#define LF1 1.24999999978138668903e-02
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#define LF2 2.23219810758559851206e-03
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_CLC_DEF void __clc_ep_log(double x, private int *xexp, private double *r1,
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private double *r2) {
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// Computes natural log(x). Algorithm based on:
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// Ping-Tak Peter Tang
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// "Table-driven implementation of the logarithm function in IEEE
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// floating-point arithmetic"
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// ACM Transactions on Mathematical Software (TOMS)
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// Volume 16, Issue 4 (December 1990)
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int near_one = x >= 0x1.e0faap-1 & x <= 0x1.1082cp+0;
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ulong ux = as_ulong(x);
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ulong uxs = as_ulong(as_double(0x03d0000000000000UL | ux) - 0x1.0p-962);
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int c = ux < IMPBIT_DP64;
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ux = c ? uxs : ux;
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int expadjust = c ? 60 : 0;
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// Store the exponent of x in xexp and put f into the range [0.5,1)
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int xexp1 = ((as_int2(ux).hi >> 20) & 0x7ff) - EXPBIAS_DP64 - expadjust;
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double f = as_double(HALFEXPBITS_DP64 | (ux & MANTBITS_DP64));
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*xexp = near_one ? 0 : xexp1;
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double r = x - 1.0;
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double u1 = MATH_DIVIDE(r, 2.0 + r);
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double ru1 = -r * u1;
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u1 = u1 + u1;
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int index = as_int2(ux).hi >> 13;
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index = ((0x80 | (index & 0x7e)) >> 1) + (index & 0x1);
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double f1 = index * 0x1.0p-7;
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double f2 = f - f1;
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double u2 = MATH_DIVIDE(f2, fma(0.5, f2, f1));
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double2 tv = USE_TABLE(ln_tbl, (index - 64));
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double z1 = tv.s0;
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double q = tv.s1;
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z1 = near_one ? r : z1;
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q = near_one ? 0.0 : q;
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double u = near_one ? u1 : u2;
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double v = u * u;
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double cc = near_one ? ru1 : u2;
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double z21 = fma(v, fma(v, fma(v, LN3, LN2), LN1), LN0);
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double z22 = fma(v, fma(v, LF2, LF1), LF0);
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double z2 = near_one ? z21 : z22;
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z2 = fma(u * v, z2, cc) + q;
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*r1 = z1;
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*r2 = z2;
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}
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#endif
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