gvisor/pkg/bits/uint64_arch_amd64.go

37 lines
1.2 KiB
Go

// Copyright 2018 Google LLC
//
// 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.
// +build amd64
package bits
// TrailingZeros64 returns the number of bits before the least significant 1
// bit in x; in other words, it returns the index of the least significant 1
// bit in x. If x is 0, TrailingZeros64 returns 64.
func TrailingZeros64(x uint64) int
// MostSignificantOne64 returns the index of the most significant 1 bit in
// x. If x is 0, MostSignificantOne64 returns 64.
func MostSignificantOne64(x uint64) int
// ForEachSetBit64 calls f once for each set bit in x, with argument i equal to
// the set bit's index.
func ForEachSetBit64(x uint64, f func(i int)) {
for x != 0 {
i := TrailingZeros64(x)
f(i)
x &^= MaskOf64(i)
}
}