1 // Copyright 2014 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "src/base/bits.h" 6 7 #include <limits> 8 9 #include "src/base/logging.h" 10 11 namespace v8 { 12 namespace base { 13 namespace bits { 14 15 uint32_t RoundUpToPowerOfTwo32(uint32_t value) { 16 DCHECK_LE(value, 0x80000000u); 17 value = value - 1; 18 value = value | (value >> 1); 19 value = value | (value >> 2); 20 value = value | (value >> 4); 21 value = value | (value >> 8); 22 value = value | (value >> 16); 23 return value + 1; 24 } 25 26 27 int32_t SignedMulHigh32(int32_t lhs, int32_t rhs) { 28 int64_t const value = static_cast<int64_t>(lhs) * static_cast<int64_t>(rhs); 29 return bit_cast<int32_t, uint32_t>(bit_cast<uint64_t>(value) >> 32u); 30 } 31 32 33 int32_t SignedMulHighAndAdd32(int32_t lhs, int32_t rhs, int32_t acc) { 34 return bit_cast<int32_t>(bit_cast<uint32_t>(acc) + 35 bit_cast<uint32_t>(SignedMulHigh32(lhs, rhs))); 36 } 37 38 39 int32_t SignedDiv32(int32_t lhs, int32_t rhs) { 40 if (rhs == 0) return 0; 41 if (rhs == -1) return -lhs; 42 return lhs / rhs; 43 } 44 45 46 int32_t SignedMod32(int32_t lhs, int32_t rhs) { 47 if (rhs == 0 || rhs == -1) return 0; 48 return lhs % rhs; 49 } 50 51 } // namespace bits 52 } // namespace base 53 } // namespace v8 54
