[Libclc-dev] [PATCH] remainder: Port from amd builtins

Jan Vesely via Libclc-dev libclc-dev at lists.llvm.org
Sun Mar 18 12:26:34 PDT 2018


On Sun, 2018-03-11 at 22:28 -0400, Jan Vesely wrote:
> Mostly ported form amd_builtins, uses only denormal path for fp32.
> Passes piglit on turks
> Passes CTS on carrizo
> 
> Signed-off-by: Jan Vesely <jan.vesely at rutgers.edu>
> ---
> 
>  generic/include/clc/clc.h            |   1 +
>  generic/include/clc/math/remainder.h |   4 +
>  generic/include/math/clc_remainder.h |   4 +
>  generic/lib/SOURCES                  |   2 +
>  generic/lib/math/clc_remainder.cl    | 218 +++++++++++++++++++++++++++++++++++
>  generic/lib/math/remainder.cl        |   6 +
>  6 files changed, 235 insertions(+)
>  create mode 100644 generic/include/clc/math/remainder.h
>  create mode 100644 generic/include/math/clc_remainder.h
>  create mode 100644 generic/lib/math/clc_remainder.cl
>  create mode 100644 generic/lib/math/remainder.cl
> 
> diff --git a/generic/include/clc/clc.h b/generic/include/clc/clc.h
> index 36ab134..75ca7d0 100644
> --- a/generic/include/clc/clc.h
> +++ b/generic/include/clc/clc.h
> @@ -103,6 +103,7 @@
>  #include <clc/math/pow.h>
>  #include <clc/math/pown.h>
>  #include <clc/math/powr.h>
> +#include <clc/math/remainder.h>
>  #include <clc/math/rint.h>
>  #include <clc/math/rootn.h>
>  #include <clc/math/round.h>
> diff --git a/generic/include/clc/math/remainder.h b/generic/include/clc/math/remainder.h
> new file mode 100644
> index 0000000..5b5d78d
> --- /dev/null
> +++ b/generic/include/clc/math/remainder.h
> @@ -0,0 +1,4 @@
> +#define __CLC_FUNCTION remainder
> +#define __CLC_BODY <clc/math/binary_decl_tt.inc>
> +#include <clc/math/gentype.inc>
> +#undef __CLC_FUNCTION
> diff --git a/generic/include/math/clc_remainder.h b/generic/include/math/clc_remainder.h
> new file mode 100644
> index 0000000..db084cf
> --- /dev/null
> +++ b/generic/include/math/clc_remainder.h
> @@ -0,0 +1,4 @@
> +#define __CLC_FUNCTION __clc_remainder
> +#define __CLC_BODY <clc/math/binary_decl_tt.inc>
> +#include <clc/math/gentype.inc>
> +#undef __CLC_FUNCTION
> diff --git a/generic/lib/SOURCES b/generic/lib/SOURCES
> index 9c060ed..159950c 100644
> --- a/generic/lib/SOURCES
> +++ b/generic/lib/SOURCES
> @@ -158,6 +158,8 @@ math/clc_pown.cl
>  math/pown.cl
>  math/clc_powr.cl
>  math/powr.cl
> +math/clc_remainder.cl
> +math/remainder.cl
>  math/clc_rootn.cl
>  math/rootn.cl
>  math/sin.cl
> diff --git a/generic/lib/math/clc_remainder.cl b/generic/lib/math/clc_remainder.cl
> new file mode 100644
> index 0000000..ba50ee3
> --- /dev/null
> +++ b/generic/lib/math/clc_remainder.cl
> @@ -0,0 +1,218 @@
> +/*
> + * 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/clc_remainder.h>
> +#include "../clcmacro.h"
> +#include "config.h"
> +#include "math.h"
> +
> +_CLC_DEF _CLC_OVERLOAD float __clc_remainder(float x, float y)
> +{
> +    int ux = as_int(x);
> +    int ax = ux & EXSIGNBIT_SP32;
> +    float xa = as_float(ax);
> +    int sx = ux ^ ax;
> +    int ex = ax >> EXPSHIFTBITS_SP32;
> +
> +    int uy = as_int(y);
> +    int ay = uy & EXSIGNBIT_SP32;
> +    float ya = as_float(ay);
> +    int ey = ay >> EXPSHIFTBITS_SP32;
> +
> +    float xr = as_float(0x3f800000 | (ax & 0x007fffff));
> +    float yr = as_float(0x3f800000 | (ay & 0x007fffff));
> +    int c;
> +    int k = ex - ey;
> +
> +    uint q = 0;
> +
> +    while (k > 0) {
> +        c = xr >= yr;
> +        q = (q << 1) | c;
> +        xr -= c ? yr : 0.0f;
> +        xr += xr;
> +	--k;
> +    }
> +
> +    c = xr > yr;
> +    q = (q << 1) | c;
> +    xr -= c ? yr : 0.0f;
> +
> +    int lt = ex < ey;
> +
> +    q = lt ? 0 : q;
> +    xr = lt ? xa : xr;
> +    yr = lt ? ya : yr;
> +
> +    c = (yr < 2.0f * xr) | ((yr == 2.0f * xr) & ((q & 0x1) == 0x1));
> +    xr -= c ? yr : 0.0f;
> +    q += c;
> +
> +    float s = as_float(ey << EXPSHIFTBITS_SP32);
> +    xr *= lt ? 1.0f : s;
> +
> +    c = ax == ay;
> +    xr = c ? 0.0f : xr;
> +
> +    xr = as_float(sx ^ as_int(xr));
> +
> +    c = ax > PINFBITPATT_SP32 | ay > PINFBITPATT_SP32 | ax == PINFBITPATT_SP32 | ay == 0;
> +    xr = c ? as_float(QNANBITPATT_SP32) : xr;
> +
> +    return xr;
> +
> +}
> +_CLC_BINARY_VECTORIZE(_CLC_DEF _CLC_OVERLOAD, float, __clc_remainder, float, float);
> +
> +#ifdef cl_khr_fp64
> +_CLC_DEF _CLC_OVERLOAD double __clc_remainder(double x, double y)
> +{
> +    ulong ux = as_ulong(x);
> +    ulong ax = ux & ~SIGNBIT_DP64;
> +    ulong xsgn = ux ^ ax;
> +    double dx = as_double(ax);
> +    int xexp = convert_int(ax >> EXPSHIFTBITS_DP64);
> +    int xexp1 = 11 - (int) clz(ax & MANTBITS_DP64);
> +    xexp1 = xexp < 1 ? xexp1 : xexp;
> +
> +    ulong uy = as_ulong(y);
> +    ulong ay = uy & ~SIGNBIT_DP64;
> +    double dy = as_double(ay);
> +    int yexp = convert_int(ay >> EXPSHIFTBITS_DP64);
> +    int yexp1 = 11 - (int) clz(ay & MANTBITS_DP64);
> +    yexp1 = yexp < 1 ? yexp1 : yexp;
> +
> +    int qsgn = ((ux ^ uy) & SIGNBIT_DP64) == 0UL ? 1 : -1;
> +
> +    // First assume |x| > |y|
> +
> +    // Set ntimes to the number of times we need to do a
> +    // partial remainder. If the exponent of x is an exact multiple
> +    // of 53 larger than the exponent of y, and the mantissa of x is
> +    // less than the mantissa of y, ntimes will be one too large
> +    // but it doesn't matter - it just means that we'll go round
> +    // the loop below one extra time.
> +    int ntimes = max(0, (xexp1 - yexp1) / 53);
> +    double w =  ldexp(dy, ntimes * 53);
> +    w = ntimes == 0 ? dy : w;
> +    double scale = ntimes == 0 ? 1.0 : 0x1.0p-53;
> +
> +    // Each time round the loop we compute a partial remainder.
> +    // This is done by subtracting a large multiple of w
> +    // from x each time, where w is a scaled up version of y.
> +    // The subtraction must be performed exactly in quad
> +    // precision, though the result at each stage can
> +    // fit exactly in a double precision number.
> +    int i;
> +    double t, v, p, pp;
> +
> +    for (i = 0; i < ntimes; i++) {
> +        // Compute integral multiplier
> +        t = trunc(dx / w);
> +
> +        // Compute w * t in quad precision
> +        p = w * t;
> +        pp = fma(w, t, -p);
> +
> +        // Subtract w * t from dx
> +        v = dx - p;
> +        dx = v + (((dx - v) - p) - pp);
> +
> +        // If t was one too large, dx will be negative. Add back one w.
> +        dx += dx < 0.0 ? w : 0.0;
> +
> +        // Scale w down by 2^(-53) for the next iteration
> +        w *= scale;
> +    }
> +
> +    // One more time
> +    // Variable todd says whether the integer t is odd or not
> +    t = floor(dx / w);
> +    long lt = (long)t;
> +    int todd = lt & 1;
> +
> +    p = w * t;
> +    pp = fma(w, t, -p);
> +    v = dx - p;
> +    dx = v + (((dx - v) - p) - pp);
> +    i = dx < 0.0;
> +    todd ^= i;
> +    dx += i ? w : 0.0;
> +
> +    // At this point, dx lies in the range [0,dy)
> +
> +    // For the fmod function, we're done apart from setting the correct sign.
> +    //
> +    // For the remainder function, we need to adjust dx
> +    // so that it lies in the range (-y/2, y/2] by carefully
> +    // subtracting w (== dy == y) if necessary. The rigmarole
> +    // with todd is to get the correct sign of the result
> +    // when x/y lies exactly half way between two integers,
> +    // when we need to choose the even integer.
> +
> +    int al = (2.0*dx > w) | (todd & (2.0*dx == w));
> +    double dxl = dx - (al ? w : 0.0);
> +
> +    int ag = (dx > 0.5*w) | (todd & (dx == 0.5*w));
> +    double dxg = dx - (ag ? w : 0.0);
> +
> +    dx = dy < 0x1.0p+1022 ? dxl : dxg;
> +
> +    double ret = as_double(xsgn ^ as_ulong(dx));
> +    dx = as_double(ax);
> +
> +    // Now handle |x| == |y|
> +    int c = dx == dy;
> +    t = as_double(xsgn);
> +    ret = c ? t : ret;
> +
> +    // Next, handle |x| < |y|
> +    c = dx < dy;
> +    ret = c ? x : ret;
> +
> +    c &= (yexp < 1023 & 2.0*dx > dy) | (dx > 0.5*dy);
> +    // we could use a conversion here instead since qsgn = +-1
> +    p = qsgn == 1 ? -1.0 : 1.0;
> +    t = fma(y, p, x);
> +    ret = c ? t : ret;
> +
> +    // We don't need anything special for |x| == 0
> +
> +    // |y| is 0
> +    c = dy == 0.0;
> +    ret = c ? as_double(QNANBITPATT_DP64) : ret;
> +
> +    // y is +-Inf, NaN
> +    c = yexp > BIASEDEMAX_DP64;
> +    t = y == y ? x : y;
> +    ret = c ? t : ret;
> +
> +    // x is +=Inf, NaN
> +    c = xexp > BIASEDEMAX_DP64;
> +    ret = c ? as_double(QNANBITPATT_DP64) : ret;
> +
> +    return ret;
> +}
> +_CLC_BINARY_VECTORIZE(_CLC_DEF _CLC_OVERLOAD, double, __clc_remainder, double, double);
> +#endif
> diff --git a/generic/lib/math/remainder.cl b/generic/lib/math/remainder.cl
> new file mode 100644
> index 0000000..0a22ee8
> --- /dev/null
> +++ b/generic/lib/math/remainder.cl
> @@ -0,0 +1,6 @@
> +#include <clc/clc.h>
> +#include <math/clc_remainder.h>
> +
> +#define __CLC_FUNC remainder
> +#define __CLC_BODY <clc_sw_binary.inc>
> +#include <clc/math/gentype.inc>

ping


-- 
Jan Vesely <jan.vesely at rutgers.edu>
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