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authorThe Android Open Source Project <initial-contribution@android.com>2008-10-21 07:00:00 -0700
committerThe Android Open Source Project <initial-contribution@android.com>2008-10-21 07:00:00 -0700
commit7c1b96a165f970a09ed239bb4fb3f1b0d8f2a407 (patch)
treedf5a6539447324de36e95b057d6b9f0361b7a250 /libs/surfaceflinger/clz.cpp
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Initial Contribution
Diffstat (limited to 'libs/surfaceflinger/clz.cpp')
-rw-r--r--libs/surfaceflinger/clz.cpp37
1 files changed, 37 insertions, 0 deletions
diff --git a/libs/surfaceflinger/clz.cpp b/libs/surfaceflinger/clz.cpp
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+/*
+ * Copyright (C) 2007 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.
+ */
+
+#include "clz.h"
+
+namespace android {
+
+int clz_impl(int32_t x)
+{
+#if defined(__arm__) && !defined(__thumb__)
+ return __builtin_clz(x);
+#else
+ if (!x) return 32;
+ int e = 31;
+ if (x&0xFFFF0000) { e -=16; x >>=16; }
+ if (x&0x0000FF00) { e -= 8; x >>= 8; }
+ if (x&0x000000F0) { e -= 4; x >>= 4; }
+ if (x&0x0000000C) { e -= 2; x >>= 2; }
+ if (x&0x00000002) { e -= 1; }
+ return e;
+#endif
+}
+
+}; // namespace android