Initial commit of Hyperscan

src/util/popcount.h

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+/*
+ * Copyright (c) 2015, Intel Corporation
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  * Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *  * Neither the name of Intel Corporation nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/** \file
+ * \brief Platform specific popcount functions
+ */
+
+#ifndef POPCOUNT_H_075D843B4545B6
+#define POPCOUNT_H_075D843B4545B6
+
+#include "ue2common.h"
+
+// We have a native popcount where the compiler has defined __POPCNT__.
+#if defined(__POPCNT__)
+#define HAVE_POPCOUNT_INSTR
+#endif
+
+#if defined(_WIN32) && defined(__AVX__) // TODO: fix win preproc
+#define HAVE_POPCOUNT_INSTR
+#define __builtin_popcount __popcnt
+#define __builtin_popcountll __popcnt64
+#endif
+
+static really_inline
+u32 popcount32(u32 x) {
+#if defined(HAVE_POPCOUNT_INSTR)
+    // Single-instruction builtin.
+    return (u32)__builtin_popcount(x);
+#else
+    // Fast branch-free version from bit-twiddling hacks as most Intel
+    // processors do not have a POPCNT instruction.
+    x -= (x >> 1) & 0x55555555;
+    x = (x & 0x33333333) + ((x >> 2) & 0x33333333);
+    return (((x + (x >> 4)) & 0xf0f0f0f) * 0x1010101) >> 24;
+#endif
+}
+
+static really_inline
+u32 popcount64(u64a x) {
+#if defined(HAVE_POPCOUNT_INSTR)
+    // Single-instruction builtin.
+    return (u32)__builtin_popcountll(x);
+#elif defined(ARCH_X86_64)
+    // Fast branch-free version from bit-twiddling hacks as most Intel
+    // processors do not have a POPCNT instruction.
+    x -= (x >> 1) & 0x5555555555555555;
+    x = (x & 0x3333333333333333) + ((x >> 2) & 0x3333333333333333);
+    x = (x + (x >> 4)) & 0x0f0f0f0f0f0f0f0f;
+    return (x * 0x0101010101010101) >> 56;
+#else
+    // Synthesise from two 32-bit cases.
+    return popcount32(x >> 32) + popcount32(x);
+#endif
+}
+
+#endif /* POPCOUNT_H_075D843B4545B6 */
+