Bitwise operators [cheat sheet]
yourbasic.org/golang
Gottfried Wilhelm Leibniz, 1697
Number literals
The binary number 100002 can be written as 020, 16 or 0x10 in Go.
| Literal | Base | Note |
|---|---|---|
020 |
8 | Starts with 0 |
16 |
10 | Never starts with 0 |
0x10 |
16 | Starts with 0x |
Built-in operators
| Operation | Result | Description |
|---|---|---|
0011 & 0101 |
0001 | Bitwise AND |
0011 | 0101 |
0111 | Bitwise OR |
0011 ^ 0101 |
0110 | Bitwise XOR |
^0101 |
1010 | Bitwise NOT (same as 1111 ^ 0101) |
0011 &^ 0101 |
0010 | Bitclear (AND NOT) |
00110101<<2 |
11010100 | Left shift |
00110101<<100 |
00000000 | No upper limit on shift count |
00110101>>2 |
00001101 | Right shift |
- The binary numbers in the examples are for explanation only. Integer literals in Go must be specified in octal, decimal or hexadecimal.
- The bitwise operators take both signed and unsigned integers as input. The right-hand side of a shift operator, however, must be an unsigned integer.
- Shift operators implement arithmetic shifts if the left operand is a signed integer and logical shifts if it is an unsigned integer.
Package math/bits
| Operation | Result | Description |
|---|---|---|
bits.UintSize |
32 or 64 | Size of a uint in bits |
bits.OnesCount8(00101110) |
4 | Number of one bits (population count) |
bits.Len8(00101110) |
6 | Bits required to represent number |
bits.Len8(00000000) |
0 | |
bits.LeadingZeros8(00101110) |
2 | Number of leading zero bits |
bits.LeadingZeros8(00000000) |
8 | |
bits.TrailingZeros8(00101110) |
1 | Number of trailing zero bits |
bits.TrailingZeros8(00000000) |
8 | |
bits.RotateLeft8(00101110, 3) |
01110001 | The value rotated left by 3 bits |
bits.RotateLeft8(00101110, -3) |
11000101 | The value rotated right by 3 bits |
bits.Reverse8(00101110) |
01110100 | Bits in reversed order |
bits.ReverseBytes16(0x00ff) |
0xff00 |
Bytes in reversed order |
- The functions operate on unsigned integers.
- They come in different forms that take arguments of different sizes.
For example,
Len,Len8,Len16,Len32, andLen64apply to the typesuint,uint8,uint16,uint32, anduint64, respectively. - The functions are recognized by the compiler and on most architectures they are treated as intrinsics for additional performance.
Bit manipulation code example
Bitmasks, bitsets and flags shows how to implement a bitmask, a small set of booleans, often called flags, represented by the bits in a single number.
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