[Libclc-dev] [PATCH] libclc/math: Add cospi
Jeroen Ketema
j.ketema at imperial.ac.uk
Mon Dec 15 15:25:33 PST 2014
Hi Aaron,
Comments inline.
> On 15 Dec 2014, at 23:14, Aaron Watry <awatry at gmail.com> wrote:
>
> Ported from the libclc/amd-builtins branch
>
> Signed-off-by: Aaron Watry <awatry at gmail.com>
> ---
> generic/include/clc/clc.h | 1 +
> generic/include/clc/math/cospi.h | 3 ++
> generic/include/clc/math/cospi.inc | 1 +
> generic/lib/SOURCES | 1 +
> generic/lib/math/cospi.cl | 96 ++++++++++++++++++++++++++++++++++++++
> generic/lib/math/sincospiF_piby4.h | 57 ++++++++++++++++++++++
> 6 files changed, 159 insertions(+)
> create mode 100644 generic/include/clc/math/cospi.h
> create mode 100644 generic/include/clc/math/cospi.inc
> create mode 100644 generic/lib/math/cospi.cl
> create mode 100644 generic/lib/math/sincospiF_piby4.h
>
> diff --git a/generic/include/clc/clc.h b/generic/include/clc/clc.h
> index bd92fdb..bff6ddd 100644
> --- a/generic/include/clc/clc.h
> +++ b/generic/include/clc/clc.h
> @@ -38,6 +38,7 @@
> #include <clc/math/atan2.h>
> #include <clc/math/copysign.h>
> #include <clc/math/cos.h>
> +#include <clc/math/cospi.h>
> #include <clc/math/ceil.h>
> #include <clc/math/exp.h>
> #include <clc/math/exp10.h>
> diff --git a/generic/include/clc/math/cospi.h b/generic/include/clc/math/cospi.h
> new file mode 100644
> index 0000000..427733b
> --- /dev/null
> +++ b/generic/include/clc/math/cospi.h
> @@ -0,0 +1,3 @@
> +#define __CLC_BODY <clc/math/cospi.inc>
> +#include <clc/math/gentype.inc>
> +#undef __CLC_BODY
> diff --git a/generic/include/clc/math/cospi.inc b/generic/include/clc/math/cospi.inc
> new file mode 100644
> index 0000000..1e786cf
> --- /dev/null
> +++ b/generic/include/clc/math/cospi.inc
> @@ -0,0 +1 @@
> +_CLC_OVERLOAD _CLC_DECL __CLC_GENTYPE cospi(__CLC_GENTYPE a);
> diff --git a/generic/lib/SOURCES b/generic/lib/SOURCES
> index b76fec9..2b9426e 100644
> --- a/generic/lib/SOURCES
> +++ b/generic/lib/SOURCES
> @@ -57,6 +57,7 @@ math/atan.cl
> math/atan2.cl
> math/copysign.cl
> math/cos.cl
> +math/cospi.cl
> math/exp.cl
> math/exp10.cl
> math/fmax.cl
> diff --git a/generic/lib/math/cospi.cl b/generic/lib/math/cospi.cl
> new file mode 100644
> index 0000000..666deb7
> --- /dev/null
> +++ b/generic/lib/math/cospi.cl
> @@ -0,0 +1,96 @@
> +/*
> + * 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 "math.h"
> +#include "sincos_helpers.h"
> +#include "sincospiF_piby4.h"
> +#include "../clcmacro.h"
> +
> +_CLC_OVERLOAD _CLC_DEF float cospi(float x)
> +{
> + int ix = as_int(x) & 0x7fffffff;
> + float ax = as_float(ix);
> + int iax = (int)ax;
> + float r = ax - iax;
> + int xodd = iax & 0x1 ? 0x80000000 : 0;
> +
> + // Initialize with return for +-Inf and NaN
> + int ir = 0x7fc00000;
> +
> + // 2^24 <= |x| < Inf, the result is always even integer
> + ir = ix < 0x7f800000 ? 0x3f800000 : ir;
> +
> + // 2^23 <= |x| < 2^24, the result is always integer
> + ir = ix < 0x4b800000 ? xodd | 0x3f800000 : ir;
> +
> + // 0x1.0p-7 <= |x| < 2^23, result depends on which 0.25 interval
> +
> + // r < 1.0
> + float a = 1.0f - r;
> + int e = 1;
> + int s = xodd ^ 0x80000000;
> +
> + // r <= 0.75
> + int c = r <= 0.75f;
> + a = c ? r - 0.5f : a;
> + e = c ? 0 : e;
> +
> + // r < 0.5
> + c = r < 0.5f;
> + a = c ? 0.5f - r : a;
> + s = c ? xodd : s;
> +
> + // r <= 0.25
> + c = r <= 0.25f;
> + a = c ? r : a;
> + e = c ? 1 : e;
> +
> + float2 t = sincosf_piby4(a * M_PI_F);
> + int jr = s ^ as_int(e ? t.hi : t.lo);
> +
> + ir = ix < 0x4b000000 ? jr : ir;
> +
> + return as_float(ir);
> +}
> +
> +
> +_CLC_UNARY_VECTORIZE(_CLC_OVERLOAD _CLC_DEF, float, cospi, float);
> +
> +#ifdef cl_khr_fp64
> +
> +#pragma OPENCL EXTENSION cl_khr_fp64 : enable
> +
> +#define __CLC_FUNCTION __clc_cos_intrinsic
> +#define __CLC_INTRINSIC “llvm.cos"
Does llvm.cos give sufficient precision for double, or is the intention to leave double as it is for now?
> +#include <clc/math/unary_intrin.inc>
> +#undef __CLC_FUNCTION
> +#undef __CLC_INTRINSIC
> +
> +_CLC_OVERLOAD _CLC_DEF double cospi(double x) {
> + return __clc_cos_intrinsic(x*M_PI);
> +}
> +
> +_CLC_UNARY_VECTORIZE(_CLC_OVERLOAD _CLC_DEF, double, cospi, double);
> +
> +#endif
> diff --git a/generic/lib/math/sincospiF_piby4.h b/generic/lib/math/sincospiF_piby4.h
> new file mode 100644
> index 0000000..3274d90
> --- /dev/null
> +++ b/generic/lib/math/sincospiF_piby4.h
> @@ -0,0 +1,57 @@
> +/*
> + * 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.
> + */
> +
> +// Evaluate single precisions in and cos of value in interval [-pi/4, pi/4]
> +inline float2
> +sincosf_piby4(float x)
Would it be possible to start prefixing the internal functions like these with some standard prefix (__libclc_ or something like that). Just the be sure they do not clash with the user’s namespace?
Also by C99’s definition of inline, you would also need to provide a non-inlined variant to make sure linking always succeeds; did you also meant to add __attribute__((always_inline)) ?
Jeroen
> +{
> + // Taylor series for sin(x) is x - x^3/3! + x^5/5! - x^7/7! ...
> + // = x * (1 - x^2/3! + x^4/5! - x^6/7! ...
> + // = x * f(w)
> + // where w = x*x and f(w) = (1 - w/3! + w^2/5! - w^3/7! ...
> + // We use a minimax approximation of (f(w) - 1) / w
> + // because this produces an expansion in even powers of x.
> +
> + // Taylor series for cos(x) is 1 - x^2/2! + x^4/4! - x^6/6! ...
> + // = f(w)
> + // where w = x*x and f(w) = (1 - w/2! + w^2/4! - w^3/6! ...
> + // We use a minimax approximation of (f(w) - 1 + w/2) / (w*w)
> + // because this produces an expansion in even powers of x.
> +
> + const float sc1 = -0.166666666638608441788607926e0F;
> + const float sc2 = 0.833333187633086262120839299e-2F;
> + const float sc3 = -0.198400874359527693921333720e-3F;
> + const float sc4 = 0.272500015145584081596826911e-5F;
> +
> + const float cc1 = 0.41666666664325175238031e-1F;
> + const float cc2 = -0.13888887673175665567647e-2F;
> + const float cc3 = 0.24800600878112441958053e-4F;
> + const float cc4 = -0.27301013343179832472841e-6F;
> +
> + float x2 = x * x;
> +
> + float2 ret;
> + ret.x = mad(x*x2, mad(x2, mad(x2, mad(x2, sc4, sc3), sc2), sc1), x);
> + ret.y = mad(x2*x2, mad(x2, mad(x2, mad(x2, cc4, cc3), cc2), cc1), mad(x2, -0.5f, 1.0f));
> + return ret;
> +}
> +
> --
> 2.1.0
>
>
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