1 files changed, 69 insertions, 0 deletions
diff --git a/libclc/generic/lib/math/exp_helper.cl b/libclc/generic/lib/math/exp_helper.cl
new file mode 100644
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+++ b/libclc/generic/lib/math/exp_helper.cl
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+/*
+ * Copyright (c) 2014, 2015 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 "tables.h"
+
+#ifdef cl_khr_fp64
+
+#pragma OPENCL EXTENSION cl_khr_fp64 : enable
+
+_CLC_DEF double __clc_exp_helper(double x, double x_min, double x_max, double r, int n) {
+
+    int j = n & 0x3f;
+    int m = n >> 6;
+
+    // 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;
+}
+
+#endif // cl_khr_fp64