/* * Copyright (C) 2012 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 unsigned roundup(unsigned v) { // __builtin_clz is undefined for zero input if (v == 0) { v = 1; } int lz = __builtin_clz((int) v); unsigned rounded = ((unsigned) 0x80000000) >> lz; // 0x800000001 and higher are actually rounded _down_ to prevent overflow if (v > rounded && lz > 0) { rounded <<= 1; } return rounded; }