1 files changed, 144 insertions, 0 deletions
diff --git a/disas/libvixl/vixl/compiler-intrinsics.cc b/disas/libvixl/vixl/compiler-intrinsics.cc
new file mode 100644
index 0000000000..fd551faeb1
--- /dev/null
+++ b/disas/libvixl/vixl/compiler-intrinsics.cc
@@ -0,0 +1,144 @@
+// Copyright 2015, ARM Limited
+// All rights reserved.
+//
+// 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 ARM Limited 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 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.
+
+#include "compiler-intrinsics.h"
+
+namespace vixl {
+
+
+int CountLeadingSignBitsFallBack(int64_t value, int width) {
+  VIXL_ASSERT(IsPowerOf2(width) && (width <= 64));
+  if (value >= 0) {
+    return CountLeadingZeros(value, width) - 1;
+  } else {
+    return CountLeadingZeros(~value, width) - 1;
+  }
+}
+
+
+int CountLeadingZerosFallBack(uint64_t value, int width) {
+  VIXL_ASSERT(IsPowerOf2(width) && (width <= 64));
+  if (value == 0) {
+    return width;
+  }
+  int count = 0;
+  value = value << (64 - width);
+  if ((value & UINT64_C(0xffffffff00000000)) == 0) {
+    count += 32;
+    value = value << 32;
+  }
+  if ((value & UINT64_C(0xffff000000000000)) == 0) {
+    count += 16;
+    value = value << 16;
+  }
+  if ((value & UINT64_C(0xff00000000000000)) == 0) {
+    count += 8;
+    value = value << 8;
+  }
+  if ((value & UINT64_C(0xf000000000000000)) == 0) {
+    count += 4;
+    value = value << 4;
+  }
+  if ((value & UINT64_C(0xc000000000000000)) == 0) {
+    count += 2;
+    value = value << 2;
+  }
+  if ((value & UINT64_C(0x8000000000000000)) == 0) {
+    count += 1;
+  }
+  count += (value == 0);
+  return count;
+}
+
+
+int CountSetBitsFallBack(uint64_t value, int width) {
+  VIXL_ASSERT(IsPowerOf2(width) && (width <= 64));
+
+  // Mask out unused bits to ensure that they are not counted.
+  value &= (UINT64_C(0xffffffffffffffff) >> (64 - width));
+
+  // Add up the set bits.
+  // The algorithm works by adding pairs of bit fields together iteratively,
+  // where the size of each bit field doubles each time.
+  // An example for an 8-bit value:
+  // Bits:  h  g  f  e  d  c  b  a
+  //         \ |   \ |   \ |   \ |
+  // value = h+g   f+e   d+c   b+a
+  //            \    |      \    |
+  // value =   h+g+f+e     d+c+b+a
+  //                  \          |
+  // value =       h+g+f+e+d+c+b+a
+  const uint64_t kMasks[] = {
+    UINT64_C(0x5555555555555555),
+    UINT64_C(0x3333333333333333),
+    UINT64_C(0x0f0f0f0f0f0f0f0f),
+    UINT64_C(0x00ff00ff00ff00ff),
+    UINT64_C(0x0000ffff0000ffff),
+    UINT64_C(0x00000000ffffffff),
+  };
+
+  for (unsigned i = 0; i < (sizeof(kMasks) / sizeof(kMasks[0])); i++) {
+    int shift = 1 << i;
+    value = ((value >> shift) & kMasks[i]) + (value & kMasks[i]);
+  }
+
+  return static_cast<int>(value);
+}
+
+
+int CountTrailingZerosFallBack(uint64_t value, int width) {
+  VIXL_ASSERT(IsPowerOf2(width) && (width <= 64));
+  int count = 0;
+  value = value << (64 - width);
+  if ((value & UINT64_C(0xffffffff)) == 0) {
+    count += 32;
+    value = value >> 32;
+  }
+  if ((value & 0xffff) == 0) {
+    count += 16;
+    value = value >> 16;
+  }
+  if ((value & 0xff) == 0) {
+    count += 8;
+    value = value >> 8;
+  }
+  if ((value & 0xf) == 0) {
+    count += 4;
+    value = value >> 4;
+  }
+  if ((value & 0x3) == 0) {
+    count += 2;
+    value = value >> 2;
+  }
+  if ((value & 0x1) == 0) {
+    count += 1;
+  }
+  count += (value == 0);
+  return count - (64 - width);
+}
+
+
+}  // namespace vixl