From 01bc96d007b67fdb7fe349232a83e4b354ce3d08 Mon Sep 17 00:00:00 2001
From: Nicolas Geoffray <ngeoffray@google.com>
Date: Fri, 11 Apr 2014 17:43:50 +0100
Subject: Long support in optimizing compiler.

- Add stack locations to the Location class.
- Change logic of parameter passing/setup by setting the
  location of such instructions the ones for the calling
  convention.

Change-Id: I4730ad58732813dcb9c238f44f55dfc0baa18799
---
 runtime/base/bit_field.h | 82 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 runtime/base/bit_field.h

(limited to 'runtime/base/bit_field.h')

diff --git a/runtime/base/bit_field.h b/runtime/base/bit_field.h
new file mode 100644
index 0000000000..e041bd0d85
--- /dev/null
+++ b/runtime/base/bit_field.h
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_RUNTIME_BASE_BIT_FIELD_H_
+#define ART_RUNTIME_BASE_BIT_FIELD_H_
+
+#include "globals.h"
+#include "logging.h"
+
+namespace art {
+
+static const uword kUwordOne = 1U;
+
+// BitField is a template for encoding and decoding a bit field inside
+// an unsigned machine word.
+template<typename T, int position, int size>
+class BitField {
+ public:
+  // Tells whether the provided value fits into the bit field.
+  static bool IsValid(T value) {
+    return (static_cast<uword>(value) & ~((kUwordOne << size) - 1)) == 0;
+  }
+
+  // Returns a uword mask of the bit field.
+  static uword Mask() {
+    return (kUwordOne << size) - 1;
+  }
+
+  // Returns a uword mask of the bit field which can be applied directly to
+  // the raw unshifted bits.
+  static uword MaskInPlace() {
+    return ((kUwordOne << size) - 1) << position;
+  }
+
+  // Returns the shift count needed to right-shift the bit field to
+  // the least-significant bits.
+  static int Shift() {
+    return position;
+  }
+
+  // Returns the size of the bit field.
+  static int BitSize() {
+    return size;
+  }
+
+  // Returns a uword with the bit field value encoded.
+  static uword Encode(T value) {
+    DCHECK(IsValid(value));
+    return static_cast<uword>(value) << position;
+  }
+
+  // Extracts the bit field from the value.
+  static T Decode(uword value) {
+    return static_cast<T>((value >> position) & ((kUwordOne << size) - 1));
+  }
+
+  // Returns a uword with the bit field value encoded based on the
+  // original value. Only the bits corresponding to this bit field
+  // will be changed.
+  static uword Update(T value, uword original) {
+    DCHECK(IsValid(value));
+    return (static_cast<uword>(value) << position) |
+        (~MaskInPlace() & original);
+  }
+};
+
+}  // namespace art
+
+#endif  // ART_RUNTIME_BASE_BIT_FIELD_H_
-- 
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