/* * Copyright 2015 WebAssembly Community Group participants * * 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. */ #ifndef wasm_support_bits_h #define wasm_support_bits_h #include #include #include /* * Portable bit functions. * * Not all platforms offer fast intrinsics for these functions, and some * compilers require checking CPUID at runtime before using the intrinsic. * * We instead use portable and reasonably-fast implementations, while * avoiding implementations with large lookup tables. */ namespace wasm { namespace Bits { int popCount(uint8_t); int popCount(uint16_t); int popCount(uint32_t); int popCount(uint64_t); inline int popCount(int8_t v) { return popCount(uint8_t(v)); } inline int popCount(int16_t v) { return popCount(uint16_t(v)); } inline int popCount(int32_t v) { return popCount(uint32_t(v)); } inline int popCount(int64_t v) { return popCount(uint64_t(v)); } uint32_t bitReverse(uint32_t); int countTrailingZeroes(uint32_t); int countTrailingZeroes(uint64_t); inline int countTrailingZeroes(int32_t v) { return countTrailingZeroes(uint32_t(v)); } inline int countTrailingZeroes(int64_t v) { return countTrailingZeroes(uint64_t(v)); } int countLeadingZeroes(uint32_t); int countLeadingZeroes(uint64_t); inline int countLeadingZeroes(int32_t v) { return countLeadingZeroes(uint32_t(v)); } inline int countLeadingZeroes(int64_t v) { return countLeadingZeroes(uint64_t(v)); } int ceilLog2(uint32_t); int ceilLog2(uint64_t); inline int ceilLog2(int32_t v) { return ceilLog2(uint32_t(v)); } inline int ceilLog2(int64_t v) { return ceilLog2(uint64_t(v)); } template bool isPowerOf2(T v) { return v != 0 && (v & (v - 1)) == 0; } bool isPowerOf2InvertibleFloat(float); bool isPowerOf2InvertibleFloat(double); template inline static T rotateLeft(T val, U count) { auto value = typename std::make_unsigned::type(val); U mask = sizeof(T) * CHAR_BIT - 1; count &= mask; return (value << count) | (value >> (-count & mask)); } template inline static T rotateRight(T val, U count) { auto value = typename std::make_unsigned::type(val); U mask = sizeof(T) * CHAR_BIT - 1; count &= mask; return (value >> count) | (value << (-count & mask)); } uint32_t log2(uint32_t v); uint32_t pow2(uint32_t v); } // namespace Bits } // namespace wasm #endif // wasm_support_bits_h