Go: Bitwise operators cheat sheet
The binary number 00010000 can be written as 020, 16 or 0x10.
| Literal | Base | Note |
|---|---|---|
020 |
8 | Starts with 0 |
16 |
10 | Never starts with 0* |
0x10 |
16 | Starts with 0x |
0 is an octal literal in Go.
Built-in operators
| Operation | Result | Description |
|---|---|---|
0011 & 0101 |
0001 | Bitwise AND |
0011 | 0101 |
0111 | Bitwise OR |
0011 ^ 0101 |
0110 | Bitwise XOR |
^0101 |
1010 | Short for 1111 ^ 0101 (NOT) |
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 |
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The binary numbers in the examples are for explanation only. Integer literals in Go must be specified in octal, decimal or hexadecimal.
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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.
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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.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 |
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These functions operate on unsigned integers.
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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.