[Libclc-dev] [PATCH 1/1] exp10: Port from amd builtins

Aaron Watry via Libclc-dev libclc-dev at lists.llvm.org
Sat Apr 14 13:08:59 PDT 2018


Reviewed and Tested (on RX 580) by: Me

--Aaron



On Wed, Apr 11, 2018 at 6:32 PM, Jan Vesely via Libclc-dev
<libclc-dev at lists.llvm.org> wrote:
> Passes CTS on carrizo and turks.
> Signed-off-by: Jan Vesely <jan.vesely at rutgers.edu>
> ---
>  generic/include/math/clc_exp10.h |   4 ++
>  generic/lib/SOURCES              |   1 +
>  generic/lib/math/clc_exp10.cl    | 149 +++++++++++++++++++++++++++++++++++++++
>  generic/lib/math/exp10.cl        |   4 +-
>  generic/lib/math/exp10.inc       |  17 -----
>  5 files changed, 157 insertions(+), 18 deletions(-)
>  create mode 100644 generic/include/math/clc_exp10.h
>  create mode 100644 generic/lib/math/clc_exp10.cl
>  delete mode 100644 generic/lib/math/exp10.inc
>
> diff --git a/generic/include/math/clc_exp10.h b/generic/include/math/clc_exp10.h
> new file mode 100644
> index 0000000..30061b6
> --- /dev/null
> +++ b/generic/include/math/clc_exp10.h
> @@ -0,0 +1,4 @@
> +#define __CLC_FUNCTION __clc_exp10
> +#define __CLC_BODY <clc/math/unary_decl.inc>
> +#include <clc/math/gentype.inc>
> +#undef __CLC_FUNCTION
> diff --git a/generic/lib/SOURCES b/generic/lib/SOURCES
> index 4b488ef..1f1a427 100644
> --- a/generic/lib/SOURCES
> +++ b/generic/lib/SOURCES
> @@ -98,6 +98,7 @@ math/exp.cl
>  math/exp_helper.cl
>  math/expm1.cl
>  math/exp2.cl
> +math/clc_exp10.cl
>  math/exp10.cl
>  math/fdim.cl
>  math/fma.cl
> diff --git a/generic/lib/math/clc_exp10.cl b/generic/lib/math/clc_exp10.cl
> new file mode 100644
> index 0000000..c6a9476
> --- /dev/null
> +++ b/generic/lib/math/clc_exp10.cl
> @@ -0,0 +1,149 @@
> +/*
> + * Copyright (c) 2014 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 "config.h"
> +#include "math.h"
> +#include "tables.h"
> +#include "../clcmacro.h"
> +
> +//    Algorithm:
> +//
> +//    e^x = 2^(x/ln(2)) = 2^(x*(64/ln(2))/64)
> +//
> +//    x*(64/ln(2)) = n + f, |f| <= 0.5, n is integer
> +//    n = 64*m + j,   0 <= j < 64
> +//
> +//    e^x = 2^((64*m + j + f)/64)
> +//        = (2^m) * (2^(j/64)) * 2^(f/64)
> +//        = (2^m) * (2^(j/64)) * e^(f*(ln(2)/64))
> +//
> +//    f = x*(64/ln(2)) - n
> +//    r = f*(ln(2)/64) = x - n*(ln(2)/64)
> +//
> +//    e^x = (2^m) * (2^(j/64)) * e^r
> +//
> +//    (2^(j/64)) is precomputed
> +//
> +//    e^r = 1 + r + (r^2)/2! + (r^3)/3! + (r^4)/4! + (r^5)/5!
> +//    e^r = 1 + q
> +//
> +//    q = r + (r^2)/2! + (r^3)/3! + (r^4)/4! + (r^5)/5!
> +//
> +//    e^x = (2^m) * ( (2^(j/64)) + q*(2^(j/64)) )
> +
> +_CLC_DEF _CLC_OVERLOAD float __clc_exp10(float x)
> +{
> +    const float X_MAX =  0x1.344134p+5f; // 128*log2/log10 : 38.53183944498959
> +    const float X_MIN = -0x1.66d3e8p+5f; // -149*log2/log10 : -44.8534693539332
> +
> +    const float R_64_BY_LOG10_2 = 0x1.a934f0p+7f; // 64*log10/log2 : 212.6033980727912
> +    const float R_LOG10_2_BY_64_LD = 0x1.340000p-8f; // log2/(64 * log10) lead : 0.004699707
> +    const float R_LOG10_2_BY_64_TL = 0x1.04d426p-18f; // log2/(64 * log10) tail : 0.00000388665057
> +    const float R_LN10 = 0x1.26bb1cp+1f;
> +
> +    int return_nan = isnan(x);
> +    int return_inf = x > X_MAX;
> +    int return_zero = x < X_MIN;
> +
> +    int n = convert_int(x * R_64_BY_LOG10_2);
> +
> +    float fn = (float)n;
> +    int j = n & 0x3f;
> +    int m = n >> 6;
> +    int m2 = m << EXPSHIFTBITS_SP32;
> +    float r;
> +
> +    r = R_LN10 * mad(fn, -R_LOG10_2_BY_64_TL, mad(fn, -R_LOG10_2_BY_64_LD, x));
> +
> +    // Truncated Taylor series for e^r
> +    float z2 = mad(mad(mad(r, 0x1.555556p-5f, 0x1.555556p-3f), r, 0x1.000000p-1f), r*r, r);
> +
> +    float two_to_jby64 = USE_TABLE(exp_tbl, j);
> +    z2 = mad(two_to_jby64, z2, two_to_jby64);
> +
> +    float z2s = z2 * as_float(0x1 << (m + 149));
> +    float z2n = as_float(as_int(z2) + m2);
> +    z2 = m <= -126 ? z2s : z2n;
> +
> +
> +    z2 = return_inf ? as_float(PINFBITPATT_SP32) : z2;
> +    z2 = return_zero ? 0.0f : z2;
> +    z2 = return_nan ? x : z2;
> +    return z2;
> +}
> +_CLC_UNARY_VECTORIZE(_CLC_DEF _CLC_OVERLOAD, float, __clc_exp10, float)
> +
> +#ifdef cl_khr_fp64
> +_CLC_DEF _CLC_OVERLOAD double __clc_exp10(double x)
> +{
> +    const double X_MAX = 0x1.34413509f79ffp+8; // 1024*ln(2)/ln(10)
> +    const double X_MIN = -0x1.434e6420f4374p+8; // -1074*ln(2)/ln(10)
> +
> +    const double R_64_BY_LOG10_2 = 0x1.a934f0979a371p+7; // 64*ln(10)/ln(2)
> +    const double R_LOG10_2_BY_64_LD = 0x1.3441350000000p-8; // head ln(2)/(64*ln(10))
> +    const double R_LOG10_2_BY_64_TL = 0x1.3ef3fde623e25p-37; // tail ln(2)/(64*ln(10))
> +    const double R_LN10 = 0x1.26bb1bbb55516p+1; // ln(10)
> +
> +    int n = convert_int(x * R_64_BY_LOG10_2);
> +
> +    double dn = (double)n;
> +
> +    int j = n & 0x3f;
> +    int m = n >> 6;
> +
> +    double r = R_LN10 * fma(-R_LOG10_2_BY_64_TL, dn, fma(-R_LOG10_2_BY_64_LD, dn, x));
> +
> +    // 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;
> +}
> +_CLC_UNARY_VECTORIZE(_CLC_DEF _CLC_OVERLOAD, double, __clc_exp10, double)
> +#endif
> diff --git a/generic/lib/math/exp10.cl b/generic/lib/math/exp10.cl
> index 1de25cb..e7456dd 100644
> --- a/generic/lib/math/exp10.cl
> +++ b/generic/lib/math/exp10.cl
> @@ -1,4 +1,6 @@
>  #include <clc/clc.h>
> +#include <math/clc_exp10.h>
>
> -#define __CLC_BODY <exp10.inc>
> +#define __CLC_FUNC exp10
> +#define __CLC_BODY <clc_sw_unary.inc>
>  #include <clc/math/gentype.inc>
> diff --git a/generic/lib/math/exp10.inc b/generic/lib/math/exp10.inc
> deleted file mode 100644
> index e4dd72c..0000000
> --- a/generic/lib/math/exp10.inc
> +++ /dev/null
> @@ -1,10 +0,0 @@
> -_CLC_OVERLOAD _CLC_DEF __CLC_GENTYPE exp10(__CLC_GENTYPE val) {
> -  // exp10(x) = exp2(x * log2(10))
> -#if __CLC_FPSIZE == 32
> -  return exp2(val * M_LOG210_F);
> -#elif __CLC_FPSIZE == 64
> -  return exp2(val * M_LOG210);
> -#else
> -#error unknown _CLC_FPSIZE
> -#endif
> -}
> --
> 2.14.3
>
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