1edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project/* 2edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * Copyright (C) 2007 The Android Open Source Project 3edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * 4edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * Licensed under the Apache License, Version 2.0 (the "License"); 5edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * you may not use this file except in compliance with the License. 6edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * You may obtain a copy of the License at 7edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * 8edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * http://www.apache.org/licenses/LICENSE-2.0 9edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * 10edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * Unless required by applicable law or agreed to in writing, software 11edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * distributed under the License is distributed on an "AS IS" BASIS, 12edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * See the License for the specific language governing permissions and 14edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * limitations under the License. 15edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project */ 16edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project 17edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project#include "clz.h" 18edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project 19edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Projectnamespace android { 20edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project 21edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Projectint clz_impl(int32_t x) 22edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project{ 23edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project#if defined(__arm__) && !defined(__thumb__) 24edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project return __builtin_clz(x); 25edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project#else 26edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project if (!x) return 32; 27edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project int e = 31; 28edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project if (x&0xFFFF0000) { e -=16; x >>=16; } 29edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project if (x&0x0000FF00) { e -= 8; x >>= 8; } 30edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project if (x&0x000000F0) { e -= 4; x >>= 4; } 31edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project if (x&0x0000000C) { e -= 2; x >>= 2; } 32edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project if (x&0x00000002) { e -= 1; } 33edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project return e; 34edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project#endif 35edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project} 36edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project 37edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project}; // namespace android 38