bits

package standard library
go1.18.10 Latest Latest
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 Go to latest Published: Jan 10, 2023 License: BSD-3-Clause Imports: 1 Imported by: 0

Documentation

Overview

Package bits implements bit counting and manipulation functions for the predeclared unsigned integer types.

Index

Examples

Constants

View Source 
const UintSize = uintSize

UintSize is the size of a uint in bits.

Variables

This section is empty.

Functions

func Add 

func Add(x, y, carry uint) (sum, carryOut uint)

Add returns the sum with carry of x, y and carry: sum = x + y + carry. The carry input must be 0 or 1; otherwise the behavior is undefined. The carryOut output is guaranteed to be 0 or 1.

This function's execution time does not depend on the inputs.

func Add32 

func Add32(x, y, carry uint32) (sum, carryOut uint32)

Add32 returns the sum with carry of x, y and carry: sum = x + y + carry. The carry input must be 0 or 1; otherwise the behavior is undefined. The carryOut output is guaranteed to be 0 or 1.

This function's execution time does not depend on the inputs.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	// First number is 33<<32 + 12
	n1 := []uint32{33, 12}
	// Second number is 21<<32 + 23
	n2 := []uint32{21, 23}
	// Add them together without producing carry.
	d1, carry := bits.Add32(n1[1], n2[1], 0)
	d0, _ := bits.Add32(n1[0], n2[0], carry)
	nsum := []uint32{d0, d1}
	fmt.Printf("%v + %v = %v (carry bit was %v)\n", n1, n2, nsum, carry)

	// First number is 1<<32 + 2147483648
	n1 = []uint32{1, 0x80000000}
	// Second number is 1<<32 + 2147483648
	n2 = []uint32{1, 0x80000000}
	// Add them together producing carry.
	d1, carry = bits.Add32(n1[1], n2[1], 0)
	d0, _ = bits.Add32(n1[0], n2[0], carry)
	nsum = []uint32{d0, d1}
	fmt.Printf("%v + %v = %v (carry bit was %v)\n", n1, n2, nsum, carry)
}

Output:

[33 12] + [21 23] = [54 35] (carry bit was 0)
[1 2147483648] + [1 2147483648] = [3 0] (carry bit was 1)

func Add64 

func Add64(x, y, carry uint64) (sum, carryOut uint64)

Add64 returns the sum with carry of x, y and carry: sum = x + y + carry. The carry input must be 0 or 1; otherwise the behavior is undefined. The carryOut output is guaranteed to be 0 or 1.

This function's execution time does not depend on the inputs.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	// First number is 33<<64 + 12
	n1 := []uint64{33, 12}
	// Second number is 21<<64 + 23
	n2 := []uint64{21, 23}
	// Add them together without producing carry.
	d1, carry := bits.Add64(n1[1], n2[1], 0)
	d0, _ := bits.Add64(n1[0], n2[0], carry)
	nsum := []uint64{d0, d1}
	fmt.Printf("%v + %v = %v (carry bit was %v)\n", n1, n2, nsum, carry)

	// First number is 1<<64 + 9223372036854775808
	n1 = []uint64{1, 0x8000000000000000}
	// Second number is 1<<64 + 9223372036854775808
	n2 = []uint64{1, 0x8000000000000000}
	// Add them together producing carry.
	d1, carry = bits.Add64(n1[1], n2[1], 0)
	d0, _ = bits.Add64(n1[0], n2[0], carry)
	nsum = []uint64{d0, d1}
	fmt.Printf("%v + %v = %v (carry bit was %v)\n", n1, n2, nsum, carry)
}

Output:

[33 12] + [21 23] = [54 35] (carry bit was 0)
[1 9223372036854775808] + [1 9223372036854775808] = [3 0] (carry bit was 1)

func Div 

func Div(hi, lo, y uint) (quo, rem uint)

Div returns the quotient and remainder of (hi, lo) divided by y: quo = (hi, lo)/y, rem = (hi, lo)%y with the dividend bits' upper half in parameter hi and the lower half in parameter lo. Div panics for y == 0 (division by zero) or y <= hi (quotient overflow).

func Div32 

func Div32(hi, lo, y uint32) (quo, rem uint32)

Div32 returns the quotient and remainder of (hi, lo) divided by y: quo = (hi, lo)/y, rem = (hi, lo)%y with the dividend bits' upper half in parameter hi and the lower half in parameter lo. Div32 panics for y == 0 (division by zero) or y <= hi (quotient overflow).

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	// First number is 0<<32 + 6
	n1 := []uint32{0, 6}
	// Second number is 0<<32 + 3
	n2 := []uint32{0, 3}
	// Divide them together.
	quo, rem := bits.Div32(n1[0], n1[1], n2[1])
	nsum := []uint32{quo, rem}
	fmt.Printf("[%v %v] / %v = %v\n", n1[0], n1[1], n2[1], nsum)

	// First number is 2<<32 + 2147483648
	n1 = []uint32{2, 0x80000000}
	// Second number is 0<<32 + 2147483648
	n2 = []uint32{0, 0x80000000}
	// Divide them together.
	quo, rem = bits.Div32(n1[0], n1[1], n2[1])
	nsum = []uint32{quo, rem}
	fmt.Printf("[%v %v] / %v = %v\n", n1[0], n1[1], n2[1], nsum)
}

Output:

[0 6] / 3 = [2 0]
[2 2147483648] / 2147483648 = [5 0]

func Div64 

func Div64(hi, lo, y uint64) (quo, rem uint64)

Div64 returns the quotient and remainder of (hi, lo) divided by y: quo = (hi, lo)/y, rem = (hi, lo)%y with the dividend bits' upper half in parameter hi and the lower half in parameter lo. Div64 panics for y == 0 (division by zero) or y <= hi (quotient overflow).

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	// First number is 0<<64 + 6
	n1 := []uint64{0, 6}
	// Second number is 0<<64 + 3
	n2 := []uint64{0, 3}
	// Divide them together.
	quo, rem := bits.Div64(n1[0], n1[1], n2[1])
	nsum := []uint64{quo, rem}
	fmt.Printf("[%v %v] / %v = %v\n", n1[0], n1[1], n2[1], nsum)

	// First number is 2<<64 + 9223372036854775808
	n1 = []uint64{2, 0x8000000000000000}
	// Second number is 0<<64 + 9223372036854775808
	n2 = []uint64{0, 0x8000000000000000}
	// Divide them together.
	quo, rem = bits.Div64(n1[0], n1[1], n2[1])
	nsum = []uint64{quo, rem}
	fmt.Printf("[%v %v] / %v = %v\n", n1[0], n1[1], n2[1], nsum)
}

Output:

[0 6] / 3 = [2 0]
[2 9223372036854775808] / 9223372036854775808 = [5 0]

func LeadingZeros 

func LeadingZeros(x uint) int

LeadingZeros returns the number of leading zero bits in x; the result is UintSize for x == 0.

func LeadingZeros16 

func LeadingZeros16(x uint16) int

LeadingZeros16 returns the number of leading zero bits in x; the result is 16 for x == 0.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("LeadingZeros16(%016b) = %d\n", 1, bits.LeadingZeros16(1))
}

Output:

LeadingZeros16(0000000000000001) = 15

func LeadingZeros32 

func LeadingZeros32(x uint32) int

LeadingZeros32 returns the number of leading zero bits in x; the result is 32 for x == 0.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("LeadingZeros32(%032b) = %d\n", 1, bits.LeadingZeros32(1))
}

Output:

LeadingZeros32(00000000000000000000000000000001) = 31

func LeadingZeros64 

func LeadingZeros64(x uint64) int

LeadingZeros64 returns the number of leading zero bits in x; the result is 64 for x == 0.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("LeadingZeros64(%064b) = %d\n", 1, bits.LeadingZeros64(1))
}

Output:

LeadingZeros64(0000000000000000000000000000000000000000000000000000000000000001) = 63

func LeadingZeros8 

func LeadingZeros8(x uint8) int

LeadingZeros8 returns the number of leading zero bits in x; the result is 8 for x == 0.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("LeadingZeros8(%08b) = %d\n", 1, bits.LeadingZeros8(1))
}

Output:

LeadingZeros8(00000001) = 7

func Len 

func Len(x uint) int

Len returns the minimum number of bits required to represent x; the result is 0 for x == 0.

func Len16 

func Len16(x uint16) (n int)

Len16 returns the minimum number of bits required to represent x; the result is 0 for x == 0.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("Len16(%016b) = %d\n", 8, bits.Len16(8))
}

Output:

Len16(0000000000001000) = 4

func Len32 

func Len32(x uint32) (n int)

Len32 returns the minimum number of bits required to represent x; the result is 0 for x == 0.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("Len32(%032b) = %d\n", 8, bits.Len32(8))
}

Output:

Len32(00000000000000000000000000001000) = 4

func Len64 

func Len64(x uint64) (n int)

Len64 returns the minimum number of bits required to represent x; the result is 0 for x == 0.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("Len64(%064b) = %d\n", 8, bits.Len64(8))
}

Output:

Len64(0000000000000000000000000000000000000000000000000000000000001000) = 4

func Len8 

func Len8(x uint8) int

Len8 returns the minimum number of bits required to represent x; the result is 0 for x == 0.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("Len8(%08b) = %d\n", 8, bits.Len8(8))
}

Output:

Len8(00001000) = 4

func Mul 

func Mul(x, y uint) (hi, lo uint)

Mul returns the full-width product of x and y: (hi, lo) = x * y with the product bits' upper half returned in hi and the lower half returned in lo.

This function's execution time does not depend on the inputs.

func Mul32 

func Mul32(x, y uint32) (hi, lo uint32)

Mul32 returns the 64-bit product of x and y: (hi, lo) = x * y with the product bits' upper half returned in hi and the lower half returned in lo.

This function's execution time does not depend on the inputs.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	// First number is 0<<32 + 12
	n1 := []uint32{0, 12}
	// Second number is 0<<32 + 12
	n2 := []uint32{0, 12}
	// Multiply them together without producing overflow.
	hi, lo := bits.Mul32(n1[1], n2[1])
	nsum := []uint32{hi, lo}
	fmt.Printf("%v * %v = %v\n", n1[1], n2[1], nsum)

	// First number is 0<<32 + 2147483648
	n1 = []uint32{0, 0x80000000}
	// Second number is 0<<32 + 2
	n2 = []uint32{0, 2}
	// Multiply them together producing overflow.
	hi, lo = bits.Mul32(n1[1], n2[1])
	nsum = []uint32{hi, lo}
	fmt.Printf("%v * %v = %v\n", n1[1], n2[1], nsum)
}

Output:

12 * 12 = [0 144]
2147483648 * 2 = [1 0]

func Mul64 

func Mul64(x, y uint64) (hi, lo uint64)

Mul64 returns the 128-bit product of x and y: (hi, lo) = x * y with the product bits' upper half returned in hi and the lower half returned in lo.

This function's execution time does not depend on the inputs.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	// First number is 0<<64 + 12
	n1 := []uint64{0, 12}
	// Second number is 0<<64 + 12
	n2 := []uint64{0, 12}
	// Multiply them together without producing overflow.
	hi, lo := bits.Mul64(n1[1], n2[1])
	nsum := []uint64{hi, lo}
	fmt.Printf("%v * %v = %v\n", n1[1], n2[1], nsum)

	// First number is 0<<64 + 9223372036854775808
	n1 = []uint64{0, 0x8000000000000000}
	// Second number is 0<<64 + 2
	n2 = []uint64{0, 2}
	// Multiply them together producing overflow.
	hi, lo = bits.Mul64(n1[1], n2[1])
	nsum = []uint64{hi, lo}
	fmt.Printf("%v * %v = %v\n", n1[1], n2[1], nsum)
}

Output:

12 * 12 = [0 144]
9223372036854775808 * 2 = [1 0]

func OnesCount 

func OnesCount(x uint) int

OnesCount returns the number of one bits ("population count") in x.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("OnesCount(%b) = %d\n", 14, bits.OnesCount(14))
}

Output:

OnesCount(1110) = 3

func OnesCount16 

func OnesCount16(x uint16) int

OnesCount16 returns the number of one bits ("population count") in x.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("OnesCount16(%016b) = %d\n", 14, bits.OnesCount16(14))
}

Output:

OnesCount16(0000000000001110) = 3

func OnesCount32 

func OnesCount32(x uint32) int

OnesCount32 returns the number of one bits ("population count") in x.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("OnesCount32(%032b) = %d\n", 14, bits.OnesCount32(14))
}

Output:

OnesCount32(00000000000000000000000000001110) = 3

func OnesCount64 

func OnesCount64(x uint64) int

OnesCount64 returns the number of one bits ("population count") in x.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("OnesCount64(%064b) = %d\n", 14, bits.OnesCount64(14))
}

Output:

OnesCount64(0000000000000000000000000000000000000000000000000000000000001110) = 3

func OnesCount8 

func OnesCount8(x uint8) int

OnesCount8 returns the number of one bits ("population count") in x.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("OnesCount8(%08b) = %d\n", 14, bits.OnesCount8(14))
}

Output:

OnesCount8(00001110) = 3

func Rem 

func Rem(hi, lo, y uint) uint

Rem returns the remainder of (hi, lo) divided by y. Rem panics for y == 0 (division by zero) but, unlike Div, it doesn't panic on a quotient overflow.

func Rem32 

func Rem32(hi, lo, y uint32) uint32

Rem32 returns the remainder of (hi, lo) divided by y. Rem32 panics for y == 0 (division by zero) but, unlike Div32, it doesn't panic on a quotient overflow.

func Rem64 

func Rem64(hi, lo, y uint64) uint64

Rem64 returns the remainder of (hi, lo) divided by y. Rem64 panics for y == 0 (division by zero) but, unlike Div64, it doesn't panic on a quotient overflow.

func Reverse 

func Reverse(x uint) uint

Reverse returns the value of x with its bits in reversed order.

func Reverse16 

func Reverse16(x uint16) uint16

Reverse16 returns the value of x with its bits in reversed order.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("%016b\n", 19)
	fmt.Printf("%016b\n", bits.Reverse16(19))
}

Output:

0000000000010011
1100100000000000

func Reverse32 

func Reverse32(x uint32) uint32

Reverse32 returns the value of x with its bits in reversed order.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("%032b\n", 19)
	fmt.Printf("%032b\n", bits.Reverse32(19))
}

Output:

00000000000000000000000000010011
11001000000000000000000000000000

func Reverse64 

func Reverse64(x uint64) uint64

Reverse64 returns the value of x with its bits in reversed order.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("%064b\n", 19)
	fmt.Printf("%064b\n", bits.Reverse64(19))
}

Output:

0000000000000000000000000000000000000000000000000000000000010011
1100100000000000000000000000000000000000000000000000000000000000

func Reverse8 

func Reverse8(x uint8) uint8

Reverse8 returns the value of x with its bits in reversed order.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("%08b\n", 19)
	fmt.Printf("%08b\n", bits.Reverse8(19))
}

Output:

00010011
11001000

func ReverseBytes 

func ReverseBytes(x uint) uint

ReverseBytes returns the value of x with its bytes in reversed order.

This function's execution time does not depend on the inputs.

func ReverseBytes16 

func ReverseBytes16(x uint16) uint16

ReverseBytes16 returns the value of x with its bytes in reversed order.

This function's execution time does not depend on the inputs.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("%016b\n", 15)
	fmt.Printf("%016b\n", bits.ReverseBytes16(15))
}

Output:

0000000000001111
0000111100000000

func ReverseBytes32 

func ReverseBytes32(x uint32) uint32

ReverseBytes32 returns the value of x with its bytes in reversed order.

This function's execution time does not depend on the inputs.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("%032b\n", 15)
	fmt.Printf("%032b\n", bits.ReverseBytes32(15))
}

Output:

00000000000000000000000000001111
00001111000000000000000000000000

func ReverseBytes64 

func ReverseBytes64(x uint64) uint64

ReverseBytes64 returns the value of x with its bytes in reversed order.

This function's execution time does not depend on the inputs.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("%064b\n", 15)
	fmt.Printf("%064b\n", bits.ReverseBytes64(15))
}

Output:

0000000000000000000000000000000000000000000000000000000000001111
0000111100000000000000000000000000000000000000000000000000000000

func RotateLeft 

func RotateLeft(x uint, k int) uint

RotateLeft returns the value of x rotated left by (k mod UintSize) bits. To rotate x right by k bits, call RotateLeft(x, -k).

This function's execution time does not depend on the inputs.

func RotateLeft16 

func RotateLeft16(x uint16, k int) uint16

RotateLeft16 returns the value of x rotated left by (k mod 16) bits. To rotate x right by k bits, call RotateLeft16(x, -k).

This function's execution time does not depend on the inputs.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("%016b\n", 15)
	fmt.Printf("%016b\n", bits.RotateLeft16(15, 2))
	fmt.Printf("%016b\n", bits.RotateLeft16(15, -2))
}

Output:

0000000000001111
0000000000111100
1100000000000011

func RotateLeft32 

func RotateLeft32(x uint32, k int) uint32

RotateLeft32 returns the value of x rotated left by (k mod 32) bits. To rotate x right by k bits, call RotateLeft32(x, -k).

This function's execution time does not depend on the inputs.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("%032b\n", 15)
	fmt.Printf("%032b\n", bits.RotateLeft32(15, 2))
	fmt.Printf("%032b\n", bits.RotateLeft32(15, -2))
}

Output:

00000000000000000000000000001111
00000000000000000000000000111100
11000000000000000000000000000011

func RotateLeft64 

func RotateLeft64(x uint64, k int) uint64

RotateLeft64 returns the value of x rotated left by (k mod 64) bits. To rotate x right by k bits, call RotateLeft64(x, -k).

This function's execution time does not depend on the inputs.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("%064b\n", 15)
	fmt.Printf("%064b\n", bits.RotateLeft64(15, 2))
	fmt.Printf("%064b\n", bits.RotateLeft64(15, -2))
}

Output:

0000000000000000000000000000000000000000000000000000000000001111
0000000000000000000000000000000000000000000000000000000000111100
1100000000000000000000000000000000000000000000000000000000000011

func RotateLeft8 

func RotateLeft8(x uint8, k int) uint8

RotateLeft8 returns the value of x rotated left by (k mod 8) bits. To rotate x right by k bits, call RotateLeft8(x, -k).

This function's execution time does not depend on the inputs.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("%08b\n", 15)
	fmt.Printf("%08b\n", bits.RotateLeft8(15, 2))
	fmt.Printf("%08b\n", bits.RotateLeft8(15, -2))
}

Output:

00001111
00111100
11000011

func Sub 

func Sub(x, y, borrow uint) (diff, borrowOut uint)

Sub returns the difference of x, y and borrow: diff = x - y - borrow. The borrow input must be 0 or 1; otherwise the behavior is undefined. The borrowOut output is guaranteed to be 0 or 1.

This function's execution time does not depend on the inputs.

func Sub32 

func Sub32(x, y, borrow uint32) (diff, borrowOut uint32)

Sub32 returns the difference of x, y and borrow, diff = x - y - borrow. The borrow input must be 0 or 1; otherwise the behavior is undefined. The borrowOut output is guaranteed to be 0 or 1.

This function's execution time does not depend on the inputs.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	// First number is 33<<32 + 23
	n1 := []uint32{33, 23}
	// Second number is 21<<32 + 12
	n2 := []uint32{21, 12}
	// Sub them together without producing carry.
	d1, carry := bits.Sub32(n1[1], n2[1], 0)
	d0, _ := bits.Sub32(n1[0], n2[0], carry)
	nsum := []uint32{d0, d1}
	fmt.Printf("%v - %v = %v (carry bit was %v)\n", n1, n2, nsum, carry)

	// First number is 3<<32 + 2147483647
	n1 = []uint32{3, 0x7fffffff}
	// Second number is 1<<32 + 2147483648
	n2 = []uint32{1, 0x80000000}
	// Sub them together producing carry.
	d1, carry = bits.Sub32(n1[1], n2[1], 0)
	d0, _ = bits.Sub32(n1[0], n2[0], carry)
	nsum = []uint32{d0, d1}
	fmt.Printf("%v - %v = %v (carry bit was %v)\n", n1, n2, nsum, carry)
}

Output:

[33 23] - [21 12] = [12 11] (carry bit was 0)
[3 2147483647] - [1 2147483648] = [1 4294967295] (carry bit was 1)

func Sub64 

func Sub64(x, y, borrow uint64) (diff, borrowOut uint64)

Sub64 returns the difference of x, y and borrow: diff = x - y - borrow. The borrow input must be 0 or 1; otherwise the behavior is undefined. The borrowOut output is guaranteed to be 0 or 1.

This function's execution time does not depend on the inputs.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	// First number is 33<<64 + 23
	n1 := []uint64{33, 23}
	// Second number is 21<<64 + 12
	n2 := []uint64{21, 12}
	// Sub them together without producing carry.
	d1, carry := bits.Sub64(n1[1], n2[1], 0)
	d0, _ := bits.Sub64(n1[0], n2[0], carry)
	nsum := []uint64{d0, d1}
	fmt.Printf("%v - %v = %v (carry bit was %v)\n", n1, n2, nsum, carry)

	// First number is 3<<64 + 9223372036854775807
	n1 = []uint64{3, 0x7fffffffffffffff}
	// Second number is 1<<64 + 9223372036854775808
	n2 = []uint64{1, 0x8000000000000000}
	// Sub them together producing carry.
	d1, carry = bits.Sub64(n1[1], n2[1], 0)
	d0, _ = bits.Sub64(n1[0], n2[0], carry)
	nsum = []uint64{d0, d1}
	fmt.Printf("%v - %v = %v (carry bit was %v)\n", n1, n2, nsum, carry)
}

Output:

[33 23] - [21 12] = [12 11] (carry bit was 0)
[3 9223372036854775807] - [1 9223372036854775808] = [1 18446744073709551615] (carry bit was 1)

func TrailingZeros 

func TrailingZeros(x uint) int

TrailingZeros returns the number of trailing zero bits in x; the result is UintSize for x == 0.

func TrailingZeros16 

func TrailingZeros16(x uint16) int

TrailingZeros16 returns the number of trailing zero bits in x; the result is 16 for x == 0.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("TrailingZeros16(%016b) = %d\n", 14, bits.TrailingZeros16(14))
}

Output:

TrailingZeros16(0000000000001110) = 1

func TrailingZeros32 

func TrailingZeros32(x uint32) int

TrailingZeros32 returns the number of trailing zero bits in x; the result is 32 for x == 0.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("TrailingZeros32(%032b) = %d\n", 14, bits.TrailingZeros32(14))
}

Output:

TrailingZeros32(00000000000000000000000000001110) = 1

func TrailingZeros64 

func TrailingZeros64(x uint64) int

TrailingZeros64 returns the number of trailing zero bits in x; the result is 64 for x == 0.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("TrailingZeros64(%064b) = %d\n", 14, bits.TrailingZeros64(14))
}

Output:

TrailingZeros64(0000000000000000000000000000000000000000000000000000000000001110) = 1

func TrailingZeros8 

func TrailingZeros8(x uint8) int

TrailingZeros8 returns the number of trailing zero bits in x; the result is 8 for x == 0.

Example 
package main

import (
	"fmt"
	"math/bits"
)

func main() {
	fmt.Printf("TrailingZeros8(%08b) = %d\n", 14, bits.TrailingZeros8(14))
}

Output:

TrailingZeros8(00001110) = 1

Types

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