2 * Copyright (C) 2007 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
21 int clz_impl(int32_t x)
23 #if defined(__arm__) && !defined(__thumb__)
24 return __builtin_clz(x);
28 if (x&0xFFFF0000) { e -=16; x >>=16; }
29 if (x&0x0000FF00) { e -= 8; x >>= 8; }
30 if (x&0x000000F0) { e -= 4; x >>= 4; }
31 if (x&0x0000000C) { e -= 2; x >>= 2; }
32 if (x&0x00000002) { e -= 1; }
37 }; // namespace android