| /* |
| * 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 |