[PATCH] libclc/math: Add cospi

Aaron Watry awatry at gmail.com
Mon Dec 15 15:14:54 PST 2014


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"
+#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)
+{
+    // 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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