nodemcu-firmware/docs/modules/bit.md

bit Module

Since	Origin / Contributor	Maintainer	Source
2014-12-24	https://github.com/LuaDist/bitlib, Zeroday	Zeroday	bit.c

Bit manipulation support, on the integer type used by the Lua VM. On 5.1 this will be 32bit, whereas on 5.3 it may be either 32bit (default) or 64bit if configured for 64bit integers.

bit.arshift()

Arithmetic right shift a number equivalent to value >> shift in C.

Syntax

bit.arshift(value, shift)

Parameters

• value the value to shift
• shift positions to shift

Returns

the number shifted right (arithmetically)

bit.band()

Bitwise AND, equivalent to val1 & val2 & ... & valn in C.

Syntax

bit.band(val1, val2 [, ... valn])

Parameters

• val1 first AND argument
• val2 second AND argument
• ...valn ...nth AND argument

Returns

the bitwise AND of all the arguments (number)

bit.bit()

Generate a number with a 1 bit (used for mask generation). Equivalent to 1 << position in C.

Syntax

bit.bit(position)

Parameters

position position of the bit that will be set to 1

Returns

a number with only one 1 bit at position (the rest are set to 0)

bit.bnot()

Bitwise negation, equivalent to `~value in C.

Syntax

bit.bnot(value)

Parameters

value the number to negate

Returns

the bitwise negated value of the number

bit.bor()

Bitwise OR, equivalent to val1 | val2 | ... | valn in C.

Syntax

bit.bor(val1, val2 [, ... valn])

Parameters

• val1 first OR argument.
• val2 second OR argument.
• ...valn ...nth OR argument

Returns

the bitwise OR of all the arguments (number)

bit.bxor()

Bitwise XOR, equivalent to val1 ^ val2 ^ ... ^ valn in C.

Syntax

bit.bxor(val1, val2 [, ... valn])

Parameters

• val1 first XOR argument
• val2 second XOR argument
• ...valn ...nth XOR argument

Returns

the bitwise XOR of all the arguments (number)

bit.clear()

Clear bits in a number.

Syntax

bit.clear(value, pos1 [, ... posn])

Parameters

• value the base number
• pos1 position of the first bit to clear
• ...posn position of thet nth bit to clear

Returns

the number with the bit(s) cleared in the given position(s)

bit.isclear()

Test if a given bit is cleared.

Syntax

bit.isclear(value, position)

Parameters

• value the value to test
• position bit position to test

Returns

true if the bit at the given position is 0, false othewise

bit.isset()

Test if a given bit is set.

Syntax

bit.isset(value, position)

Parameters

• value the value to test
• position bit position to test

Returns

true if the bit at the given position is 1, false otherwise

bit.lshift()

Left-shift a number, equivalent to value << shift in C.

Syntax

bit.lshift(value, shift)

Parameters

• value the value to shift
• shift positions to shift

Returns

the number shifted left

bit.rshift()

Logical right shift a number, equivalent to ( unsigned )value >> shift in C.

Syntax

bit.rshift(value, shift)

Parameters

• value the value to shift.
• shift positions to shift.

Returns

the number shifted right (logically)

bit.set()

Set bits in a number.

Syntax

bit.set(value, pos1 [, ... posn ])

Parameters

• value the base number.
• pos1 position of the first bit to set.
• ...posn position of the nth bit to set.

Returns

the number with the bit(s) set in the given position(s)